UK Small Area Statistics Unit - Research Database NN4B

This Agreement permits Imperial College London to continue to hold the NN4B data disseminated by ONS, but not to otherwise process it.

The Small Area Health Statistics Unit (SAHSU) is a long-standing and internationally recognised centre of excellence assessing the risk of exposure to environmental pollutants to the health of the population, with an emphasis on the use and interpretation of routine health statistics at small-area level. SAHSU was established in 1987 as a recommendation of the Black enquiry into the incidence of leukaemia and lymphoma in children and young adults near the Windscale/Sellafield nuclear power plant

SAHSU has a unique role nationally in carrying out environmental health surveillance of the population in relation to environmental contaminants and point sources of industrial pollution, based on routinely collected health data. This is a highly specialised area of work requiring excellence in computing, database management, geographical information systems (GIS), statistics, environmental exposure assessment and epidemiology. The set of skills and expertise that has been established and built up in SAHSU is a unique resource both nationally and worldwide.

SAHSU holds comprehensive computerised sets of health and demographic data and a range of environmental datasets at high spatial resolution.

SAHSU has a programme of work established by the UK Health Security Agency (UKHSA; formerly Public Health England) to contribute to public health in the UK which is defined by the following terms of reference:

• to develop and maintain comprehensive health and environmental databases;

• to carry out substantive studies on potential environmental risks to health;

• to respond rapidly to ad hoc queries about unusual clusters of disease;

• to develop small-area statistical methodology;

• to act as a centre of expertise, disseminating information on developments in spatial epidemiological methods to regional, national and international groups.

• to respond rapidly, with expert advice, to ad hoc queries from the core funding bodies (Department of Health and Social Care (DHSC) and UKHSA) about unusual clusters of disease, particularly in the neighbourhood of industrial installations.

To deliver against the Terms of Reference, SAHSU utilises the research database to meet the following purposes:

Purpose 1 - To develop and maintain comprehensive health and environmental databases

At the core of the overall programme of work is the maintenance of the SAHSU research database, which combines multiple datasets and has both ethics and s251 approvals in place.

SAHSU has developed an extensive collection of environmental exposure data e.g. air pollution, magnetic fields, environmental noise, that SAHSU holds at a high spatial resolution, together with geographically-referenced health data as needed in approved studies - all SAHSU studies are controlled via the UKHSA-SAHSU Liaison Committee. An example of this work is the Environment and Health Atlas for England and Wales, which included 14 conditions (nine cancers) at small area level (website http://www.envhealthatlas.co.uk/homepage/ and OUP book: Hansell AL, Beale LA, Ghosh RE, Fortunato L, Fecht D, Jarup L, Elliott P. The Environment and Health Atlas for England and Wales. Oxford University Press, April 2014, Oxford, UK.).In 2021, SAHSU has collaborated with DISCOVER-NOW HDRUK Hub for Real-world evidence synthesis to link modelled long-term air pollution exposure to participants in North West London’s Whole Systems Integrated Care (WSIC, integrated care record) at the individual level based on residential postcode. This data will be used going forwards to study the impact of air pollution on health outcomes.

A particular strength is the maintenance of historic data, which allows SAHSU to examine long term trends and use of data at high spatial resolution, which are crucial for studies of environmental exposures determined by spatial location e.g. electromagnetic field exposure arising from proximity to an overhead power line; noise pollution arising from residential proximity to aircraft flight paths.

Purpose 2 - to carry out substantive studies on potential environmental risks to health

The research programme includes both methods development and investigation of priority questions in environment and health. A key aim is to improve the science base underlying translation of knowledge on the effects of the environment on health into policy. SAHSU conducts national research studies on environmental factors that may affect health ranging from exposures to e.g. traffic-related air pollution, road and aircraft noise, water contaminants, waste disposal, green and blue space, using nationally collected patient data including mortality, hospital admissions, cancer registrations and births data. Additional small-area analyses are conducted that help support the general remit of the unit e.g. investigating differential hospital admission rates in ethnically diverse neighbourhoods. SAHSU provides national expertise in cluster detection and small-area statistical methods and has close links with UKHSA including input into UKHSA's surveillance activities.

Purpose 3 - To respond rapidly to ad hoc queries about unusual clusters of disease

Such work is carried out on the instruction of Department of Health and Social Care or UKHSA, and is approved by the Director of SAHSU. By its nature, such requirements cannot be detailed in advance, but the only outputs provided would be aggregated with small numbers suppressed.

Purpose 4 - To develop small-area statistical methodology for analysing and interpreting health outcomes

Some of SAHSU's studies are methodological, relating to, for example, statistical uncertainty in observed health risks in areas relating to choice of spatial boundaries or uncertainties in the population estimates; development of methods to detect clusters of disease in time and space (surveillance); development of methods to better adjust for lifestyle factors in health risk analyses by using risk scores constructed at area-level from cohort datasets and surveys in SAHSU's analyses of hospital admissions and mortality.

Purpose 5 - To act as a centre of expertise, disseminating information on developments in spatial epidemiological methods to national and regional groups

SAHSU participate in national and international scientific meetings and provide training to UKHSA and internationally including to the US Centers for Disease Control (CDC) in the use of small area analysis for public health purposes. SAHSU use aggregate non-disclosive data in outputs, presentations and training.

Purpose 6 - To provide rapid ad hoc support to UKHSA and DHSC about unusual clusters of disease, particularly in the neighbourhood of industrial installations

Such work is carried out on the instruction of Department of Health and Social Care or UKHSA, and is approved by the Director of SAHSU. By its nature, such requirements cannot be detailed in advance, but outputs provided would be aggregated with small numbers suppressed. The Rapid Enquiry Facility (RIF) tool - (see below) could be used for such work in the future.

The Rapid Enquiry Facility (RIF) is an automated software tool that uses both database and Geographic Information System (GIS) technologies to rapidly address epidemiological and public health questions using routinely collected health and population data. This allows SAHSU to respond rapidly, with expert advice to ad hoc queries from the funding departments about unusual clusters of disease, particularly in the neighbourhood of industrial installations. The RIF can perform risk analysis around putative hazardous sources and can be used for disease mapping. It generates standardised rates and relative risks for any given health outcome, for specified age and year ranges, for any given geographical area. This facility was initially designed as a tool for SAHSU staff to analyse routinely collected health data in relation to environmental exposures. The software has general public health utility and was further developed as part of the European Health and Environment Information System (EUROHEIS) project and as part of the US Centers for Disease Control (CDC) environmental public health tracking programme.

The RIF study facilitates spatial epidemiological analyses, relating spatial and non-spatial data. Two types of analysis can be carried out with the RIF: risk analysis around putative hazardous sources and disease mapping. The RIF calculates and can map rates and relative risks either by distance around one or more selected point, line or area sources, or groups of areas defined by exposure levels. Previous versions of the RIF have been widely disseminated, and used by public health departments in the USA, Canada and Europe. Redevelopment of the RIF is currently paused due to funding constraints. v4.0 will be freely available for application in any public health setting and with particular usefulness in initial epidemiological investigations of potential clusters of disease, in relation to environmental contamination such as around industrial sites, and disease surveillance.

Approval of projects

SAHSU has a unique role to support UKHSA and the devolved administrations in their mission to protect the health and wellbeing of the population with respect to environment and health concerns. SAHSU undertakes a programme of research, surveillance and cluster investigation, subject to funding from external sources, that includes both methods development and investigation of priority questions in environment and health (including social, economic and demographic factors) as approved through UKHSA governance.

The governance is overseen by the UKHSA-SAHSU Liaison Committee that has a Terms of Reference document describing the purpose, scope, membership and authority of the committee. Most SAHSU studies are funded through peer-reviewed grants from research councils such as UKRI, NIHR (including the Health Protection Research Units which are a collaboration with UKHSA) and the Wellcome Trust and other charities e.g. the Cystic Fibrosis Trust. Even though UKHSA provided the core infrastructure funding for SAHSU and there is an active no-cost extension to this agreement, they do not have any decision making responsibilities over the project initiations within the SAHSU unit and are therefore not considered a Data Controller.

Project/study initiations are done by researchers within SAHSU. All new studies using SAHSU data must be approved as a "SAHSU-study". To do so, researchers have to provide a project outline detailing the project rationale, its relevance to patients and the public (i.e. health and/or social care) and which data will be required. The study can then be approved by either the Director or Deputy Director of SAHSU under consideration of SAHSU's overall programme terms of reference and whether the study is adequately covered by SAHSU's existing ethical approval and if not, separate ethical approval must be sought.

Once approved internally, the project is introduced to UKHSA via the UKHSA-SAHSU Liaison Committee which will provide confirmation that the project falls within the UKHSA-SAHSU funding remit and will then be forwarded to get formal minuted approval from the appropriate UKHSA programme board attended by a member of the DHSC (e.g. Environmental Hazard Board).

SAHSU has a single s251 support in place to cover the above. Any project which may have additional requirements (for example to require the linkage of an additional dataset beyond that previously agreed) must seek an amendment to existing s251 and ethics approvals. It would also be outside the scope of this application, and therefore an amendment would be put before IGARD for consideration.

ONS NN4B (2006-2012)

SAHSU currently holds ONS NN4B data from the period 2006 to 2012 which have been used to link to the ONS birth registrations (live and stillbirth). SAHSU have HRA-CAG approval (Ref - 20/CAG/0028) and London - South East Research Ethics Committee approval (Ref: 17/LO/0846) to hold and link ONS Birth registrations to NN4B data. SAHSU has not been able to get more up to date NN4B data from ONS, as of 2015 NN4B has been replaced with the Personal Demographics Service and is now managed by NHS England.

The gestational age and ethnicity information from NN4B were added to ONS birth registration data to create an enhanced dataset for use in SAHSU research.

The gestational age information is useful for SAHSU research for the following reasons:

1) gestational age is needed to correctly define low birth weight data some babies have a low birth weight due to being born early rather than any actual growth retardation;

2) to more accurately define trimester/pregnancy-specific exposures by allowing a day of conception (i.e. the first day of potential exposure) to be calculated;

3) to define specific reproductive outcomes such as pre-term delivery. Adjustment for ethnicity is crucial in a range of studies and without individual-level data area-level measures of ethnicity must be used.

4) Evaluation of birth weight trends

5) Construction of Birth weight charts sex-specific and ethnic-specific

6) Validation of the existing birth weight charts and evaluation of the misclassification rates

7) Evaluation of stillbirths in relation to birth weight charts

This can be problematic as many reproductive outcomes are strongly linked to ethnicity, for example, birth weight varies amongst ethnic groups and without individual ethnicity information definitions and interpretation of low birth weight is less accurate.

The enhanced birth dataset (ONS birth registration + NN4B) and more up-to-date births data with gestational age information would allow for current trends in births weight and birth weight distributions to be investigated.

The NN4B/Birth Notification dataset is an invaluable dataset because it combines individual-level information on ethnicity and gestational age, which are both essential to being able to properly interpret birthweight – babies of ethnic minority groups and/or who are born earlier tend to weigh less. This is particularly important to know about and to be able to adjust for in statistical analyses in London, as there are high percentages of ethnic minority groups living in areas experiencing high aircraft noise exposure. This is important for this study, which is likely to influence policy on aircraft traffic.

SAHSU have previously evaluated ONS birth registration, HES and NN4B datasets (Ghosh RE, Ashworth DC, Hansell AL, Garwood K, Elliott P, Toledano MB. Routinely collected English birth data sets: comparisons and recommendations for reproductive epidemiology. Arch Dis Child Fetal Neonatal Ed. 2016 Sep;101(5):F451-7) and concluded that NN4B was the best dataset to use in epidemiological studies. Alternative datasets are not as good and may lead to biased estimates of any associations between noise and birth outcomes – ONS birth registrations do not have information on gestational age or ethnicity; HES data have issues with the completeness of both information and coverage.

Having national data will enable SAHSU to provide the ad-hoc rapid response to UKHSA, Department of Health and Social Care etc. Given that PHE's coverage is across England, and the requirements cannot be predicted in advance, national data is required given that response times do not permit time to request, receive and process individual extracts of data. Historical data is also essential for all projects to enable SAHSU to obtain longitudinal data on prior admissions for patients.

The following projects are on hold until the NN4B/Birth Notifications/Registrations data is made available to SAHSU.

1. Evaluation of birth weight trends:

Birth weight centiles updated with the data 2012-18 (up to the available year) and small for gestational age centiles to be used as a threshold to define small for gestational age (SGA) outcome in future environmental epidemiology studies

2. Evaluation of stillbirths in relation to birth weight charts:

Analysis of the effect of stillbirths in relation to Birth weight centiles.

3. Construction of Birth weight charts sex-specific and ethnic-specific:

Birth weight trends to investigate the evolution of trends in England and Wales, (including data from 1986-2012) and to identify change points and analysis in the relation of ethical differences.

4. Validation of the existing birth weight charts and evaluation of the misclassification rates:

Validation of the actual birth weight chart with the most recent data, to investigate based on the birth weight trends if updated are required due to changes in population distribution

The following projects will commence once the NN4B/Birth Notifications/Registrations data is made available to SAHSU:

Public Health Impacts of Clean Air Zones: This MRC funded study will explore the health impacts of the London Ultra Low Emission Zone (ULEZ). The ULEZ is predicted to positively impact health outcomes by reducing the exposure of residents living within the ULEX to traffic-related air pollution. This project aims to measure the health impacts (including low birth weight) and assess whether the health impacts differ depending on demographic or socio-economic factors. The findings will inform local and national policy on clean air zones.

Pathways to equitable health in cities: This Wellcome Trust funded study aims to understand the impacts of planning and policy actions on the social, natural and build environment on population health (including preterm birth and low birth weight) and health inequalities. The study will directly inform actions that influence people’s health. In London, the study will collaborate with the Greater London Authority and UKHSA.

The GDPR lawful basis for SAHSU to process this data is Article 6(1)(e) 'task in the public interest' and Article 9(2)(j) 'scientific or historical research purposes or statistical purposes'.

This Agreement permits the secure retention of the data only and no other processing.

No new outputs will be produced under this Data Sharing Agreement.

SAHSU's proposed work will continue with the same themes of SAHSU’s programme of work agreed with UKHSA. Some examples of SAHSU's studies that have previously required ONS Birth registration data linked to NN4B/Birth Notification data are:

Incinerators:

This is a national study of birth outcomes near Municipal Waste Incinerators during 2003-10 (http://www.sahsu.org/content/incinerators-study) that investigated the following questions: Are the emissions from incinerators required to operate under the standards set by the EU Waste Incineration Directive (WID) (2000/76/EC) linked with adverse reproductive and infant health outcomes? Is living near a municipal waste incinerator (MWI) linked with adverse reproductive and infant health outcomes? The study was commissioned to extend the evidence base and to provide further information to the public about any potential reproductive and infant health risks from MWIs and to extend the evidence base with respect to exposures and any potential reproductive and infant health risks from MWIs.

Maternal residential exposure to aircraft and railway noise and risks of adverse birth outcomes:

The study investigated whether there is an impact of aircraft noise exposure from Heathrow airport on the birth weight of babies living near the airport. There is good biological plausibility through noise-induced stress and also the known associations of environmental noise on blood pressure that may affect blood flow to the placenta. The analysis follows on from the SAHSU ‘Traffic in London’ study recently published in the BMJ (Smith RB, Fecht D, Gulliver J, Beevers SD, Dajnak D, Blangiardo M, Ghosh RE, Hansell AL, Kelly FJ, Anderson HR, Toledano MB. Impact of London's road traffic air and noise pollution on birth weight: retrospective population-based cohort study. BMJ. 2017 Dec 5;359:j5299), which examined road traffic noise using the NN4B dataset. The study suggested potential impacts at the highest levels of road traffic noise exposure. The impact of aircraft noise on birth weight are important to assess, as aircraft noise exposures are higher in some areas than road traffic noise and that the quality of the noise of an aircraft flying overhead means that noise is more intrusive, also in London aircraft overfly heavily populated areas.

Green Space and Birth Outcomes:

The availability of green space has been linked to multiple health benefits, with recent studies in the USA and Europe suggesting a link between improved birth outcomes and residential exposure to green space. The aim of this SAHSU study was to explore the associations between green space and birth outcomes in London.

Traffic pollution and health in London:

This MRC centre study aims to describe and understand the patterns of exposure of the population in London to traffic pollution (including air and noise) and their relationships to health (http://www.kcl.ac.uk/lsm/research/divisions/aes/research/ERG/research-projects/traffic/index.aspx). The consortium of over 20 investigators has a wide range of work packages. SAHSU related deliverables are to quantify relationships between traffic noise and air pollution and the following health outcomes: mortality, hospital admissions and adverse birth outcomes including low birth weight in the study period 2003-10.

Air pollution data came from the Environmental Research Group at Kings College and noise exposures have been modelled at Imperial. ONS birth registrations are linked with NN4B data to generate an enhanced and added-value ONS birth dataset with gestation age and ethnicity which is important for accurate exposure estimation and outcome interpretation. Maternal residential addresses at the time of birth are used in order to accurately estimate exposures at residential addresses.

Small for gestational age (SGA):

Small for gestational age (SGA) is normally defined as a baby with a weight below the 10th percentile for their sex and gestational age. Defining the gender-specific birth weight for gestational age can be done in two ways, 1) a within study distribution or; 2) using pre-defined centile charts based on other studies. The main pre-defined reference curves currently in use in the UK are based on the British 1990 (UK90) reference which is based on measurements from white British children born between 1983 and 1994. Additional ethnic-specific centile charts have since been produced. A recent study investigated whether the UK90 centile charts predicted neonatal outcomes better than an ethnic-specific one using data from 9102 births in the Born in Bradford cohort. This project uses national data for the whole of England and Wales (2006-2014) to calculate national centile charts, including ethnic-specific centile charts. These are used to calculate the risk of being SGA as compared to using the UK90 and ethnic-specific centile charts.

Smoking ban:

This study examined the impact of the smoke-free legislation on rates of preterm birth, low birth weight (LBW) and small for gestational age (SGA). As a consequence of the Health Act 2006, England successfully implemented comprehensive smoke-free legislation in July 2007, prohibiting smoking in all enclosed or partially enclosed public spaces. Few studies have examined the impact of interventions to reduce exposure to second-hand smoke on pregnancy outcomes.

This Agreement permits the secure retention of the data only and no other processing.

The focus of our work is to investigate key public health issues associated with environmental factors at a small area scale. SAHSU research findings are fed back to relevant policy leads within the UK Health Security Agency (UKHSA), and other government departments which are used to consider population health risks and to inform national public health policy.

Our research findings are placed in the public domain via peer-reviewed publications and presented at scientific meetings and conferences to inform policy and to empower public debate. Some publications and presentations using our research database and/or directly arising from our project work from the last annual review are listed below.

Published peer-reviewed articles:

Bennett JE, Rashid T, Zolfaghari A, Doyle Y, Suel E, Pearson-Stuttard J, Davies B, Fecht D, Muller ES, Nathvani RS, Sportliche N, Daby HI, Johnson E, Li G, Flaxman S, Toledano MB, Asaria M, Ezzati M. Changes in life expectancy and house prices in London from 2022 to 2019: hyper-resolution spatiotemporal analysis of death registration and real estate data. Lancet Regional health-Europe 2023; Apr. 27: 1005890. https://doi.org/10.1016/j.lanepe.2022.100580.

Fuertes E, Jarvis D, Lam H, Davies B, Fecht D, Candeias J, Schmidt-Weber CB, Abdel Douiri A, Slovick A, Scala E, E.L. Smith TEL, Shamji M, Buters JTM, Cecchi L, Till SJ. Phl p 5 levels more strongly associated than grass pollen counts with allergic respiratory health. J Allergy and Clin Immunol, 2023; Nov. 153(3): 844-851. https://doi.org/10.1016/j.jaci.2023.11.011.

Itzkowitz N, Gong X, Adams K, Jephcote C, Gulliver J, HanselL AL, Blangiardo M. Aircraft noise and cardiovascular morbidity and mortality near Heathrow Airport: a case-crossover study. Environment International. Vol.177, July 2023, 108016. doi 10.1016/J.ENVINT.2023.108016.

Khan MS, Douglas P, Hansell AL, Simmonds NJ, Piel FB. Assessing the health risk of living near composting facilities on lung health, fungal and bacterial disease in cystic fibrosis: a UK CF Registry study. Environ Health 2022; Dec. 21(1): 130. Doi: 10.1186/s12940-022-00932-1

Konstantinoudis G, Cameletti M, Gomez-Rubio V, Gomez IL, Pirani M, Baio G, Larrauri A, Riou J, Egger M, Vineis P, Blangiardo M. Regional excess mortality during the 2020 COVID-19 pandemic in five European countries. Nature Comms 2022; Jan. 13(482).

Doi: 10.1038/s41467-022-28157-3

Parkes B, Stafoggia M, Fecht D, Davies B, Bonander C, De' Donato F, Michelozzi P, Piel FB, Stroemberg U, Blangiardo M. Community factors and excess mortality in the COVID pandemic in England, Italy and Sweden. Eur J Public Health 2023; Aug. 33(4): 695-703. Doi: 10.1093/eurpub/ckad075

Rashid T, Bennett JE, Muller DC, Cross AJ, Pearson-Stuttard J, Asaria P, Daby HI, Fecht D, Davies B, Ezzati M. Mortality from leading cancers in districts of England from 2002 to 2019: a population-based, spatiotemporal study. The Lancet Oncology, 2023, Dec. 25(10: 86-98.

https://doi.org/10.1016/S1470-2045(23)00530-2. (This publication received widespread media coverage including in The Guardian, The Times, Daily Mirror, Telegraph, Metro, BBC News, etc.)

Roca-Barcelo A, Crabbe H, Close R, Fahie H, Leonardi GS, Piel FB. Spatial and temporal trends and risk factors for intentional carbon monoxide poisoning hospitalizations in England between 2002 and 2016. J Affective Disorders; 2023; May. 329: 168-175. Doi: 10.1016/J.JAD.2023.02.036

Wang W, Gulliver J, Beevers S, Freni Sterrantino A, Davies B, Atkinson RW, Fecht D. Short-Term Nitrogen Dioxide Exposure and Emergency Hospital Admissions for Asthma in Children: A Case-Crossover Analysis in England. J Asthma Allergy, 2024; 17:349-359. Doi: 10.2147/JAA.S448600

Fecht D, Chadeau-Hyam M, Owen R, Gregson J, Halliday BP, Lota AS, Gulliver J, Ware JS, Pennell DJ, Kelly FJ, Shah ASV, Miller MR, Newby DE, Prasad SK, Tayal U. Exposure to elevated nitrogen dioxide concentrations and cardiac remodelling in patients with dilated cardiomyopathy. Journal of Cardiac Failure. 2022 Jun;28(6):924-934. doi: 10.1016/j.cardfail.2021.11.023

Asaria P, Bennett J, Elliott P, Rashid T, Daby H, Douglass M, Francis D, Fecht D, Ezzati M, 2022, Contributions of event rates, pre-hospital deaths and hospital case fatality to variations in myocardial infarction mortality in 326 districts in England: spatial analysis of linked hospitalisation and mortality data, The Lancet Public Health, 022 Oct;7(10):e813-e824.

doi: 10.1016/S2468-2667(22)00108-6

Konstantinoudis G, Minelli C, Vicedo Cabrera A, Ballester J, Gasparrini,A and Blangiardo M (2022). Ambient heat exposure and COPD hospitalisations in England: A nationwide case-crossover study during 2007-2018.Thorax. Nov;77(11):1098-1104. doi: 10.1136/thoraxjnl-2021-218374

Evangelopoulos D, Dajnak D, Wood D, Fecht D, Walton H (2022). Health impact assessment of current and past air pollution on asthma in London. Report for Greater London Authority. https://www.imperial.ac.uk/media/imperial-college/medicine/sph/environmental-research-group/Health-Impact-Assessment-of-current-and-past-Air-Pollution-on-asthma-in-London.pdf

Presentations and conference abstracts:

Beevers S. The air quality health and economic costs and benefits of a zero carbon UK? A study of road traffic and building heating. Presentation to The Committee on the Medical Effects of Air Pollution (COMEAP), 31 January 2024. (project used SAHSU data).

Beevers S. The air quality health and economic costs and benefits of a zero carbon UK? A study of road traffic and building heating. ISEE - International Society of Environmental Epidemiology in Taiwan, September 2023.

Chamberlain R., Davies B., Hodsoll J., Fecht D. Impact of the central London Ultra-Low Emission Zone and toxicity-charge on adult emergency hospital admissions: An interrupted time series analysis. ISEE (International Society of Environmental Epidemiology) Taiwan, 18 September 2023.

Evangelopoulos D, Wood D, Dajnak D, Beevers S, Assareh N, Beddows A, Vu T, Stewart G, Fecht D, Davies B, Brand C and Walton H. Net Zero policies in the UK: The air pollution co benefits on mortality and morbidity. Respirami Conference, Milan, Italy, 1 March 2024.

Konstantinoudis G. Asthma hospitalisations and heat exposure in England: a case–crossover study during 2002–2019. ISEE (International Society of Environmental Epidemiology) Taiwan, 18 September 2023.

Wang, W. Brownfield sites. UKHSA Conference, Leeds UK, November 2023.

Wang, W. Children’s spaces. UKHSA Conference, Leeds UK, November 2023.

James Bennett, The interlinked dynamics of house process and life expectancy in London. International Conference on Urban Health in Valencia on 24th October 2022.

Gianluca Baio, One year of COVID-19 in 5 major European countries: a comparative analysis of excess mortality. GEOMED conference, Irvine (US), 12-14 October 2022.

Monica Pirani, A statistical framework for evaluating the health effects of PM sources, Annual conference of the Italian Statistical Society, Caserta (Italy), 21 June 2022.

Oral presentation at the 2022 UKHSA Annual UK Research Review Meeting on Outdoor and Indoor Air Pollution Research and Planning of the Health Impacts Assessment of air pollution and asthma project.

Bucyibaruta, G. (2022). Italian Statistics Society, 21st June 2022. Oral presentation on apportionment framework for particulate contaminants.

Chamberlain R, Fecht D, Davies B, Laverty A. Impacts of Low Emission and Congestion Charging Zones on physical health outcomes: a systematic review. Lancet PH conference 25 November 2022.

Fuertes E, Jarvis D, Lam H, Davies B, Fecht D, Buters J, Cecchi L, Till S. Associations between grass pollen counts and allergen (Phl p 5) levels with respiratory allergic health outcomes – 34th Annual Conference of International Society for Environmental Epidemiology. 18-21 September 2022. Athens, Greece. Project 2019/11/04 (PollenLITE).

Saleem Khan, M., Simmonds, N. & Piel, F.B. (2022). Investigating associations between air pollution and the severity of cystic fibrosis in Great Britain. 45th European Cystic Fibrosis Conference. 8-11 June. Rotterdam, NL.

Wang W. Short-term exposure to nitrogen dioxide and emergency hospital admissions in England: A time-stratified case-crossover study. 15th Annual 15th Annual UK and Ireland Occupational and Environmental Epidemiology Conference. 4th April 2022.

This Agreement permits Imperial College London to continue to hold the NN4B data disseminated by ONS, but not to otherwise process it.

The Small Area Health Statistics Unit (SAHSU) is a long-standing and internationally recognised centre of excellence assessing the risk of exposure to environmental pollutants to the health of the population, with an emphasis on the use and interpretation of routine health statistics at small-area level. SAHSU was established in 1987 as a recommendation of the Black enquiry into the incidence of leukaemia and lymphoma in children and young adults near the Windscale/Sellafield nuclear power plant

SAHSU has a unique role nationally in carrying out environmental health surveillance of the population in relation to environmental contaminants and point sources of industrial pollution, based on routinely collected health data. This is a highly specialised area of work requiring excellence in computing, database management, geographical information systems (GIS), statistics, environmental exposure assessment and epidemiology. The set of skills and expertise that has been established and built up in SAHSU is a unique resource both nationally and worldwide.

SAHSU holds comprehensive computerised sets of health and demographic data and a range of environmental datasets at high spatial resolution.

SAHSU has a programme of work established by the UK Health Security Agency (UKHSA; formerly Public Health England) to contribute to public health in the UK which is defined by the following terms of reference:

• to develop and maintain comprehensive health and environmental databases;

• to carry out substantive studies on potential environmental risks to health;

• to respond rapidly to ad hoc queries about unusual clusters of disease;

• to develop small-area statistical methodology;

• to act as a centre of expertise, disseminating information on developments in spatial epidemiological methods to regional, national and international groups.

• to respond rapidly, with expert advice, to ad hoc queries from the core funding bodies (Department of Health and Social Care (DHSC) and UKHSA) about unusual clusters of disease, particularly in the neighbourhood of industrial installations.

To deliver against the Terms of Reference, SAHSU utilises the research database to meet the following purposes:

Purpose 1 - To develop and maintain comprehensive health and environmental databases

At the core of the overall programme of work is the maintenance of the SAHSU research database, which combines multiple datasets and has both ethics and s251 approvals in place.

SAHSU has developed an extensive collection of environmental exposure data e.g. air pollution, magnetic fields, environmental noise, that SAHSU holds at a high spatial resolution, together with geographically-referenced health data as needed in approved studies - all SAHSU studies are controlled via the UKHSA-SAHSU Liaison Committee. An example of this work is the Environment and Health Atlas for England and Wales, which included 14 conditions (nine cancers) at small area level (website http://www.envhealthatlas.co.uk/homepage/ and OUP book: Hansell AL, Beale LA, Ghosh RE, Fortunato L, Fecht D, Jarup L, Elliott P. The Environment and Health Atlas for England and Wales. Oxford University Press, April 2014, Oxford, UK.).In 2021, SAHSU has collaborated with DISCOVER-NOW HDRUK Hub for Real-world evidence synthesis to link modelled long-term air pollution exposure to participants in North West London’s Whole Systems Integrated Care (WSIC, integrated care record) at the individual level based on residential postcode. This data will be used going forwards to study the impact of air pollution on health outcomes.

A particular strength is the maintenance of historic data, which allows SAHSU to examine long term trends and use of data at high spatial resolution, which are crucial for studies of environmental exposures determined by spatial location e.g. electromagnetic field exposure arising from proximity to an overhead power line; noise pollution arising from residential proximity to aircraft flight paths.

Purpose 2 - to carry out substantive studies on potential environmental risks to health

The research programme includes both methods development and investigation of priority questions in environment and health. A key aim is to improve the science base underlying translation of knowledge on the effects of the environment on health into policy. SAHSU conducts national research studies on environmental factors that may affect health ranging from exposures to e.g. traffic-related air pollution, road and aircraft noise, water contaminants, waste disposal, green and blue space, using nationally collected patient data including mortality, hospital admissions, cancer registrations and births data. Additional small-area analyses are conducted that help support the general remit of the unit e.g. investigating differential hospital admission rates in ethnically diverse neighbourhoods. SAHSU provides national expertise in cluster detection and small-area statistical methods and has close links with UKHSA including input into UKHSA's surveillance activities.

Purpose 3 - To respond rapidly to ad hoc queries about unusual clusters of disease

Such work is carried out on the instruction of Department of Health and Social Care or UKHSA, and is approved by the Director of SAHSU. By its nature, such requirements cannot be detailed in advance, but the only outputs provided would be aggregated with small numbers suppressed.

Purpose 4 - To develop small-area statistical methodology for analysing and interpreting health outcomes

Some of SAHSU's studies are methodological, relating to, for example, statistical uncertainty in observed health risks in areas relating to choice of spatial boundaries or uncertainties in the population estimates; development of methods to detect clusters of disease in time and space (surveillance); development of methods to better adjust for lifestyle factors in health risk analyses by using risk scores constructed at area-level from cohort datasets and surveys in SAHSU's analyses of hospital admissions and mortality.

Purpose 5 - To act as a centre of expertise, disseminating information on developments in spatial epidemiological methods to national and regional groups

SAHSU participate in national and international scientific meetings and provide training to UKHSA and internationally including to the US Centers for Disease Control (CDC) in the use of small area analysis for public health purposes. SAHSU use aggregate non-disclosive data in outputs, presentations and training.

Purpose 6 - To provide rapid ad hoc support to UKHSA and DHSC about unusual clusters of disease, particularly in the neighbourhood of industrial installations

Such work is carried out on the instruction of Department of Health and Social Care or UKHSA, and is approved by the Director of SAHSU. By its nature, such requirements cannot be detailed in advance, but outputs provided would be aggregated with small numbers suppressed. The Rapid Enquiry Facility (RIF) tool - (see below) could be used for such work in the future.

The Rapid Enquiry Facility (RIF) is an automated software tool that uses both database and Geographic Information System (GIS) technologies to rapidly address epidemiological and public health questions using routinely collected health and population data. This allows SAHSU to respond rapidly, with expert advice to ad hoc queries from the funding departments about unusual clusters of disease, particularly in the neighbourhood of industrial installations. The RIF can perform risk analysis around putative hazardous sources and can be used for disease mapping. It generates standardised rates and relative risks for any given health outcome, for specified age and year ranges, for any given geographical area. This facility was initially designed as a tool for SAHSU staff to analyse routinely collected health data in relation to environmental exposures. The software has general public health utility and was further developed as part of the European Health and Environment Information System (EUROHEIS) project and as part of the US Centers for Disease Control (CDC) environmental public health tracking programme.

The RIF study facilitates spatial epidemiological analyses, relating spatial and non-spatial data. Two types of analysis can be carried out with the RIF: risk analysis around putative hazardous sources and disease mapping. The RIF calculates and can map rates and relative risks either by distance around one or more selected point, line or area sources, or groups of areas defined by exposure levels. Previous versions of the RIF have been widely disseminated, and used by public health departments in the USA, Canada and Europe. Redevelopment of the RIF is currently paused due to funding constraints. v4.0 will be freely available for application in any public health setting and with particular usefulness in initial epidemiological investigations of potential clusters of disease, in relation to environmental contamination such as around industrial sites, and disease surveillance.

Approval of projects

SAHSU has a unique role to support UKHSA and the devolved administrations in their mission to protect the health and wellbeing of the population with respect to environment and health concerns. SAHSU undertakes a programme of research, surveillance and cluster investigation, subject to funding from external sources, that includes both methods development and investigation of priority questions in environment and health (including social, economic and demographic factors) as approved through UKHSA governance.

The governance is overseen by the UKHSA-SAHSU Liaison Committee that has a Terms of Reference document describing the purpose, scope, membership and authority of the committee. Most SAHSU studies are funded through peer-reviewed grants from research councils such as UKRI, NIHR (including the Health Protection Research Units which are a collaboration with UKHSA) and the Wellcome Trust and other charities e.g. the Cystic Fibrosis Trust. Even though UKHSA provided the core infrastructure funding for SAHSU and there is an active no-cost extension to this agreement, they do not have any decision making responsibilities over the project initiations within the SAHSU unit and are therefore not considered a Data Controller.

Project/study initiations are done by researchers within SAHSU. All new studies using SAHSU data must be approved as a "SAHSU-study". To do so, researchers have to provide a project outline detailing the project rationale, its relevance to patients and the public (i.e. health and/or social care) and which data will be required. The study can then be approved by either the Director or Deputy Director of SAHSU under consideration of SAHSU's overall programme terms of reference and whether the study is adequately covered by SAHSU's existing ethical approval and if not, separate ethical approval must be sought.

Once approved internally, the project is introduced to UKHSA via the UKHSA-SAHSU Liaison Committee which will provide confirmation that the project falls within the UKHSA-SAHSU funding remit and will then be forwarded to get formal minuted approval from the appropriate UKHSA programme board attended by a member of the DHSC (e.g. Environmental Hazard Board).

SAHSU has a single s251 support in place to cover the above. Any project which may have additional requirements (for example to require the linkage of an additional dataset beyond that previously agreed) must seek an amendment to existing s251 and ethics approvals. It would also be outside the scope of this application, and therefore an amendment would be put before IGARD for consideration.

ONS NN4B (2006-2012)

SAHSU currently holds ONS NN4B data from the period 2006 to 2012 which have been used to link to the ONS birth registrations (live and stillbirth). SAHSU have HRA-CAG approval (Ref - 20/CAG/0028) and London - South East Research Ethics Committee approval (Ref: 17/LO/0846) to hold and link ONS Birth registrations to NN4B data. SAHSU has not been able to get more up to date NN4B data from ONS, as of 2015 NN4B has been replaced with the Personal Demographics Service and is now managed by NHS England.

The gestational age and ethnicity information from NN4B were added to ONS birth registration data to create an enhanced dataset for use in SAHSU research.

The gestational age information is useful for SAHSU research for the following reasons:

1) gestational age is needed to correctly define low birth weight data some babies have a low birth weight due to being born early rather than any actual growth retardation;

2) to more accurately define trimester/pregnancy-specific exposures by allowing a day of conception (i.e. the first day of potential exposure) to be calculated;

3) to define specific reproductive outcomes such as pre-term delivery. Adjustment for ethnicity is crucial in a range of studies and without individual-level data area-level measures of ethnicity must be used.

4) Evaluation of birth weight trends

5) Construction of Birth weight charts sex-specific and ethnic-specific

6) Validation of the existing birth weight charts and evaluation of the misclassification rates

7) Evaluation of stillbirths in relation to birth weight charts

This can be problematic as many reproductive outcomes are strongly linked to ethnicity, for example, birth weight varies amongst ethnic groups and without individual ethnicity information definitions and interpretation of low birth weight is less accurate.

The enhanced birth dataset (ONS birth registration + NN4B) and more up-to-date births data with gestational age information would allow for current trends in births weight and birth weight distributions to be investigated.

The NN4B/Birth Notification dataset is an invaluable dataset because it combines individual-level information on ethnicity and gestational age, which are both essential to being able to properly interpret birthweight – babies of ethnic minority groups and/or who are born earlier tend to weigh less. This is particularly important to know about and to be able to adjust for in statistical analyses in London, as there are high percentages of ethnic minority groups living in areas experiencing high aircraft noise exposure. This is important for this study, which is likely to influence policy on aircraft traffic.

SAHSU have previously evaluated ONS birth registration, HES and NN4B datasets (Ghosh RE, Ashworth DC, Hansell AL, Garwood K, Elliott P, Toledano MB. Routinely collected English birth data sets: comparisons and recommendations for reproductive epidemiology. Arch Dis Child Fetal Neonatal Ed. 2016 Sep;101(5):F451-7) and concluded that NN4B was the best dataset to use in epidemiological studies. Alternative datasets are not as good and may lead to biased estimates of any associations between noise and birth outcomes – ONS birth registrations do not have information on gestational age or ethnicity; HES data have issues with the completeness of both information and coverage.

Having national data will enable SAHSU to provide the ad-hoc rapid response to UKHSA, Department of Health and Social Care etc. Given that PHE's coverage is across England, and the requirements cannot be predicted in advance, national data is required given that response times do not permit time to request, receive and process individual extracts of data. Historical data is also essential for all projects to enable SAHSU to obtain longitudinal data on prior admissions for patients.

The following projects are on hold until the NN4B/Birth Notifications/Registrations data is made available to SAHSU.

1. Evaluation of birth weight trends:

Birth weight centiles updated with the data 2012-18 (up to the available year) and small for gestational age centiles to be used as a threshold to define small for gestational age (SGA) outcome in future environmental epidemiology studies

2. Evaluation of stillbirths in relation to birth weight charts:

Analysis of the effect of stillbirths in relation to Birth weight centiles.

3. Construction of Birth weight charts sex-specific and ethnic-specific:

Birth weight trends to investigate the evolution of trends in England and Wales, (including data from 1986-2012) and to identify change points and analysis in the relation of ethical differences.

4. Validation of the existing birth weight charts and evaluation of the misclassification rates:

Validation of the actual birth weight chart with the most recent data, to investigate based on the birth weight trends if updated are required due to changes in population distribution

The following projects will commence once the NN4B/Birth Notifications/Registrations data is made available to SAHSU:

Public Health Impacts of Clean Air Zones: This MRC funded study will explore the health impacts of the London Ultra Low Emission Zone (ULEZ). The ULEZ is predicted to positively impact health outcomes by reducing the exposure of residents living within the ULEX to traffic-related air pollution. This project aims to measure the health impacts (including low birth weight) and assess whether the health impacts differ depending on demographic or socio-economic factors. The findings will inform local and national policy on clean air zones.

Pathways to equitable health in cities: This Wellcome Trust funded study aims to understand the impacts of planning and policy actions on the social, natural and build environment on population health (including preterm birth and low birth weight) and health inequalities. The study will directly inform actions that influence people’s health. In London, the study will collaborate with the Greater London Authority and UKHSA.

The GDPR lawful basis for SAHSU to process this data is Article 6(1)(e) 'task in the public interest' and Article 9(2)(j) 'scientific or historical research purposes or statistical purposes'.

This Agreement permits the secure retention of the data only and no other processing.

No new outputs will be produced under this Data Sharing Agreement.

SAHSU's proposed work will continue with the same themes of SAHSU’s programme of work agreed with UKHSA. Some examples of SAHSU's studies that have previously required ONS Birth registration data linked to NN4B/Birth Notification data are:

Incinerators:

This is a national study of birth outcomes near Municipal Waste Incinerators during 2003-10 (http://www.sahsu.org/content/incinerators-study) that investigated the following questions: Are the emissions from incinerators required to operate under the standards set by the EU Waste Incineration Directive (WID) (2000/76/EC) linked with adverse reproductive and infant health outcomes? Is living near a municipal waste incinerator (MWI) linked with adverse reproductive and infant health outcomes? The study was commissioned to extend the evidence base and to provide further information to the public about any potential reproductive and infant health risks from MWIs and to extend the evidence base with respect to exposures and any potential reproductive and infant health risks from MWIs.

Maternal residential exposure to aircraft and railway noise and risks of adverse birth outcomes:

The study investigated whether there is an impact of aircraft noise exposure from Heathrow airport on the birth weight of babies living near the airport. There is good biological plausibility through noise-induced stress and also the known associations of environmental noise on blood pressure that may affect blood flow to the placenta. The analysis follows on from the SAHSU ‘Traffic in London’ study recently published in the BMJ (Smith RB, Fecht D, Gulliver J, Beevers SD, Dajnak D, Blangiardo M, Ghosh RE, Hansell AL, Kelly FJ, Anderson HR, Toledano MB. Impact of London's road traffic air and noise pollution on birth weight: retrospective population-based cohort study. BMJ. 2017 Dec 5;359:j5299), which examined road traffic noise using the NN4B dataset. The study suggested potential impacts at the highest levels of road traffic noise exposure. The impact of aircraft noise on birth weight are important to assess, as aircraft noise exposures are higher in some areas than road traffic noise and that the quality of the noise of an aircraft flying overhead means that noise is more intrusive, also in London aircraft overfly heavily populated areas.

Green Space and Birth Outcomes:

The availability of green space has been linked to multiple health benefits, with recent studies in the USA and Europe suggesting a link between improved birth outcomes and residential exposure to green space. The aim of this SAHSU study was to explore the associations between green space and birth outcomes in London.

Traffic pollution and health in London:

This MRC centre study aims to describe and understand the patterns of exposure of the population in London to traffic pollution (including air and noise) and their relationships to health (http://www.kcl.ac.uk/lsm/research/divisions/aes/research/ERG/research-projects/traffic/index.aspx). The consortium of over 20 investigators has a wide range of work packages. SAHSU related deliverables are to quantify relationships between traffic noise and air pollution and the following health outcomes: mortality, hospital admissions and adverse birth outcomes including low birth weight in the study period 2003-10.

Air pollution data came from the Environmental Research Group at Kings College and noise exposures have been modelled at Imperial. ONS birth registrations are linked with NN4B data to generate an enhanced and added-value ONS birth dataset with gestation age and ethnicity which is important for accurate exposure estimation and outcome interpretation. Maternal residential addresses at the time of birth are used in order to accurately estimate exposures at residential addresses.

Small for gestational age (SGA):

Small for gestational age (SGA) is normally defined as a baby with a weight below the 10th percentile for their sex and gestational age. Defining the gender-specific birth weight for gestational age can be done in two ways, 1) a within study distribution or; 2) using pre-defined centile charts based on other studies. The main pre-defined reference curves currently in use in the UK are based on the British 1990 (UK90) reference which is based on measurements from white British children born between 1983 and 1994. Additional ethnic-specific centile charts have since been produced. A recent study investigated whether the UK90 centile charts predicted neonatal outcomes better than an ethnic-specific one using data from 9102 births in the Born in Bradford cohort. This project uses national data for the whole of England and Wales (2006-2014) to calculate national centile charts, including ethnic-specific centile charts. These are used to calculate the risk of being SGA as compared to using the UK90 and ethnic-specific centile charts.

Smoking ban:

This study examined the impact of the smoke-free legislation on rates of preterm birth, low birth weight (LBW) and small for gestational age (SGA). As a consequence of the Health Act 2006, England successfully implemented comprehensive smoke-free legislation in July 2007, prohibiting smoking in all enclosed or partially enclosed public spaces. Few studies have examined the impact of interventions to reduce exposure to second-hand smoke on pregnancy outcomes.

This Agreement permits the secure retention of the data only and no other processing

Examples of how outputs from SAHSU’s studies are being used to inform health policy include:

Smoking ban:

This study examined the impact of the smoke-free legislation on rates of preterm birth, low birth weight (LBW) and small for gestational age (SGA). As a consequence of the Health Act 2006, England successfully implemented comprehensive smoke-free legislation in July 2007, prohibiting smoking in all enclosed or partially enclosed public spaces. Few studies have examined the impact of interventions to reduce exposure to second-hand smoke on pregnancy outcomes.

Protective effects of smoke-free legislation on birth outcomes in England - a regression discontinuity design. Bakolis, Ioannis; Kelly, Ruth; Fecht, Daniela; Best, Nicky; Millett, Christopher; Garwood, Kevin; Elliott, Paul; Hansell, Anna L; Hodgson, Susan. Published ahead of print - doi: 10.1097/EDE.0000000000000534 available http://journals.lww.com/epidem/Abstract/publishahead/Protective_effects_of_smoke_free_legislation_on.98989.aspx

Susan Hodgson ‘video abstract’ on this paper is available here: https://journals.lww.com/epidem/Pages/videogallery.aspx?videoId=33&autoPlay=true

Posters presentations:

Poster (Regression discontinuity design and policy evaluation: an evaluation of smoke-free legislation on birth outcomes. Ioannis Bakolis, Ruth Kelly, Daniela Fecht, Nicky Best, Anna Hansell, Christopher Millett, Kevin Garwood and Susan Hodgson) - 8th UK and Ireland Occupational & Environmental Epidemiology Meeting, London, April 2014

Poster (Smoke-Free Legislation and Adverse Pregnancy Outcomes in England

Ioannis Bakolis, Ruth Kelly, Daniela Fecht, Nicky Best, Anna Hansell, Christopher Millett, Kevin Garwood, Paul Elliot , Susan Hodgson) International Society of Environmental Epidemiology, Seattle, Washington, August 2014

Poster (Regression Discontinuity Design and Policy Evaluation: an Evaluation of Smoke-Free Legislation on Adverse Pregnancy Outcomes Ioannis Bakolis, Nicky Best, Daniela Fecht, Anna Hansell, Christopher Millett, Paul Elliot, Kevin Garwood, Ruth Kelly, Susan Hodgson, International Society of Environmental Epidemiology, Seattle, Washington, August 2014

The results of SAHSU studies are placed in the public domain via peer-reviewed publications and presenting results at scientific meetings and conferences and are used to inform the behaviour of health care providers and to inform national public health policy. To reach relevant stakeholders, SAHSU puts out press releases in collaboration with the Imperial College Press Office and holds press conferences, where relevant (e.g. as part of the re-launch of the SAHSU Environment and Health Atlas for England and Wales). All studies equally feedback their results into the relevant policy leads within UKHSA and UKHSA is informed of any outputs ahead of publication.

Where results are likely to be of particular interest, SAHSU puts out a press release and, if necessary, hold a press conference e.g. for the SAHSU Environment and Health Atlas for England and Wales published in 2014, SAHSU held a press conference and several media interviews, including the Assistant Director of SAHSU being interviewed on the BBC Radio 4 Today programme. SAHSU also respond to media enquiries relevant to SAHSU’s work e.g. the former Assistant Director of SAHSU took part in a Newsnight report on health effects of air pollution, broadcast 17 October 2016.SAHSU also present its work at scientific advisory committees where of particular national interest e.g. some of SAHSU's work on the incinerators project was considered during meetings of the Committee on Carcinogenicity (COC) and the Committee on Toxicity of Chemicals in foods, consumer products and the environment (COT).

SAHSU puts details of its research on the SAHSU website (http://www.imperial.ac.uk/school-public-health/epidemiology-and-biostatistics/small-area-health-statistics-unit/), including publications and outputs. For the SAHSU Environment and Health Atlas for England and Wales, SAHSU developed a public-facing website with interactive searchable maps and explanatory text (www.envhealthatlas.co.uk) working with the NGO Sense About Science.

SAHSU takes part in a wide range of public-facing events, both general and project-specific For example, in June 2016, members of SAHSU presented work at the ‘Life Bank- Interactive Science Event’ as part of MRC Festival of Medical Research which targeted young members of the public aged 18-40 years old, including on the Environment and Health Atlas for England and Wales (involving nine cancer outcomes mapped at small area level across England and Wales), bioaerosols and health effects of environmental noise. See video at https://www.youtube.com/watch?v=ml4XyHs720I - A look at how your environment affects your health at the MRC festival.

SAHSU will continue to present and seek feedback on work and also approaches to data handling to the MRC Centre Public and Community Oversight Group. In addition, also meets with various community organisations and provides research updates and meetings with government departments.

In 2017, 2018 and 2019, members of SAHSU presented work at Imperial Festival, the university’s annual public engagement showcase. In 2017, SAHSU members contributed to exhibits on both the health benefits of green space and more generally on the health effects of environmental pollutants such as air pollution and noise. In 2018, the Centre for Environment and Health organised exhibits on both exposomics, and more specifically on work related to SAHSU in an exhibit entitled “Big data, small areas”, which involved demonstrating the Environment and Health Atlas for England and Wales, outlining how SAHSU uses routine health and environmental data and also covering noise and air pollution in London. In 2019 SAHSU presented an art installation on the perception of urban green space.

The Centre for Environment and Health and the Health Protection Research Units (Environmental Exposures and Health HPRU and Chemical and Radiation Threats and Hazards HPRU) have a joint public and community advisory group.

This agreement permits Imperial College London to continue to hold the NN4B data disseminated by ONS, but not to otherwise process it.

The Small Area Health Statistics Unit (SAHSU) is a long-standing and internationally recognised centre of excellence assessing the risk of exposure to environmental pollutants to the health of the population, with an emphasis on the use and interpretation of routine health statistics at small-area level. SAHSU was established in 1987 as a recommendation of the Black enquiry into the incidence of leukaemia and lymphoma in children and young adults near the Windscale/Sellafield nuclear power plant

SAHSU has a unique role nationally in carrying out environmental health surveillance of the population in relation to environmental contaminants and point sources of industrial pollution, based on routinely collected health data. This is a highly specialised area of work requiring excellence in computing, database management, geographical information systems (GIS), statistics, environmental exposure assessment and epidemiology. The set of skills and expertise that has been established and built up in SAHSU is a unique resource both nationally and worldwide.

SAHSU holds comprehensive computerised sets of health and demographic data and a range of environmental datasets at high spatial resolution.

SAHSU is funded by Public Health England (PHE) to contribute to public health in the UK. SAHSU has a programme of work established which is defined by the following terms of reference: -

• to develop and maintain comprehensive health and environmental databases;

• to carry out substantive studies on potential environmental risks to health;

• to respond rapidly to ad hoc queries about unusual clusters of disease;

• to develop small-area statistical methodology;

• to act as a centre of expertise, disseminating information on developments in spatial epidemiological methods to regional, national and international groups.

• to respond rapidly, with expert advice, to ad hoc queries from the core funding bodies (Department of Health and Public Health England) about unusual clusters of disease, particularly in the neighbourhood of industrial installations.

To deliver against the Terms of Reference, SAHSU utilises the research database to meet the following purposes:

Purpose 1 - To develop and maintain comprehensive health and environmental databases

At the core of the overall programme of work is the maintenance of the SAHSU research database, which combines multiple datasets and has both ethics and s251 approvals in place.

SAHSU has developed an extensive collection of environmental exposure data e.g. air pollution, magnetic fields, environmental noise, that SAHSU holds at a high spatial resolution, together with geographically-referenced health data as needed in approved studies - all SAHSU studies are controlled via the PHE-SAHSU Liaison Committee. An example of this work is the Environment and Health Atlas for England and Wales, which included 14 conditions (nine cancers) at small area level (website http://www.envhealthatlas.co.uk/homepage/ and OUP book: Hansell AL, Beale LA, Ghosh RE, Fortunato L, Fecht D, Jarup L, Elliott P. The Environment and Health Atlas for England and Wales. Oxford University Press, April 2014, Oxford, UK.).In 2021, SAHSU has collaborated with DISCOVER-NOW HDRUK Hub for Real-world evidence synthesis to link modelled long-term air pollution exposure to participants in North West London’s Whole Systems Integrated Care (WSIC, integrated care record) at the individual level based on residential postcode. This data will be used going forwards to study the impact of air pollution on health outcomes.

A particular strength is the maintenance of historic data, which allows SAHSU to examine long term trends and use of data at high spatial resolution, which are crucial for studies of environmental exposures determined by spatial location e.g. electromagnetic field exposure arising from proximity to an overhead power line; noise pollution arising from residential proximity to aircraft flight paths.

Purpose 2 - to carry out substantive studies on potential environmental risks to health

The research programme includes both methods development and investigation of priority questions in environment and health. A key aim is to improve the science base underlying translation of knowledge on the effects of the environment on health into policy. SAHSU conducts national research studies on environmental factors that may affect health ranging from exposures to e.g. traffic-related air pollution, road and aircraft noise, water contaminants, waste disposal, green and blue space, using nationally collected patient data including mortality, hospital admissions, cancer registrations and births data. Additional small-area analyses are conducted that help support the general remit of the unit e.g. investigating differential hospital admission rates in ethnically diverse neighbourhoods. SAHSU provides national expertise in cluster detection and small-area statistical methods and has close links with Public Health England including input into PHE's surveillance activities.

Purpose 3 - To respond rapidly to ad hoc queries about unusual clusters of disease

Such work is carried out on the instruction of Department of Health and Social Care or Public Health England, and is approved by the Director of SAHSU. By its nature, such requirements cannot be detailed in advance, but the only outputs provided would be aggregated with small numbers suppressed.

Purpose 4 - To develop small-area statistical methodology for analysing and interpreting health outcomes

Some of SAHSU's studies are methodological, relating to, for example, statistical uncertainty in observed health risks in areas relating to choice of spatial boundaries or uncertainties in the population estimates; development of methods to detect clusters of disease in time and space (surveillance); development of methods to better adjust for lifestyle factors in health risk analyses by using risk scores constructed at area-level from cohort datasets and surveys in SAHSU's analyses of hospital admissions and mortality.

Purpose 5 - To act as a centre of expertise, disseminating information on developments in spatial epidemiological methods to national and regional groups

SAHSU participate in national and international scientific meetings and provide training to PHE and internationally including to the US Centers for Disease Control (CDC) in the use of small area analysis for public health purposes. SAHSU use aggregate non-disclosive data in outputs, presentations and training.

Purpose 6 - To provide rapid ad hoc support to PHE and DH about unusual clusters of disease, particularly in the neighbourhood of industrial installations

Such work is carried out on the instruction of Department of Health and Social Care or Public Health England, and is approved by the Director of SAHSU. By its nature, such requirements cannot be detailed in advance, but outputs provided would be aggregated with small numbers suppressed. The Rapid Enquiry Facility (RIF) tool - (see below) could be used for such work in the future.

The Rapid Enquiry Facility (RIF) is an automated software tool that uses both database and Geographic Information System (GIS) technologies to rapidly address epidemiological and public health questions using routinely collected health and population data. This allows SAHSU to respond rapidly, with expert advice to ad hoc queries from the funding departments about unusual clusters of disease, particularly in the neighbourhood of industrial installations. The RIF can perform risk analysis around putative hazardous sources and can be used for disease mapping. It generates standardised rates and relative risks for any given health outcome, for specified age and year ranges, for any given geographical area. This facility was initially designed as a tool for SAHSU staff to analyse routinely collected health data in relation to environmental exposures. The software has general public health utility and was further developed as part of the European Health and Environment Information System (EUROHEIS) project and as part of the US Centers for Disease Control (CDC) environmental public health tracking programme.

The RIF study facilitates spatial epidemiological analyses, relating spatial and non-spatial data. Two types of analysis can be carried out with the RIF: risk analysis around putative hazardous sources and disease mapping. The RIF calculates and can map rates and relative risks either by distance around one or more selected point, line or area sources, or groups of areas defined by exposure levels. Previous versions of the RIF have been widely disseminated, and used by public health departments in the USA, Canada and Europe. Redevelopment of the RIF is currently paused due to funding constraints. v4.0 will be freely available for application in any public health setting and with particular usefulness in initial epidemiological investigations of potential clusters of disease, in relation to environmental contamination such as around industrial sites, and disease surveillance.

Approval of projects

SAHSU has a unique role to support PHE and the devolved administrations in their mission to protect the health and wellbeing of the population with respect to environment and health concerns. SAHSU undertakes a programme of research, surveillance and cluster investigation, subject to funding from external sources, that includes both methods development and investigation of priority questions in environment and health (including social, economic and demographic factors) as approved through PHE governance.

The governance is overseen by the PHE-SAHSU Liaison Committee that has a Terms of Reference document describing the purpose, scope, membership and authority of the committee. Most SAHSU studies are funded through peer-reviewed grants from research councils such as UKRI, NIHR (including the Health Protection Research Units which are a collaboration with PHE) and the Wellcome Trust and other charities e.g. the Cystic Fibrosis Trust. Even though PHE provided the core infrastructure funding for SAHSU and there is an active no-cost extension to this agreement, they do not have any decision making responsibilities over the project initiations within the SAHSU unit and are therefore not considered a Data Controller.

Project/study initiations are done by researchers within SAHSU. All new studies using SAHSU data must be approved as a "SAHSU-study". To do so, researchers have to provide a project outline detailing the project rationale, its relevance to patients and the public (i.e. health and/or social care) and which data will be required. The study can then be approved by either the Director or Deputy Director of SAHSU under consideration of SAHSU's overall programme terms of reference and whether the study is adequately covered by SAHSU's existing ethical approval and if not, separate ethical approval must be sought.

Once approved internally, the project is introduced to PHE via the PHE-SAHSU Liaison Committee which will provide confirmation that the project falls within the PHE-SAHSU funding remit and will then be forwarded to get formal minuted approval from the appropriate PHE programme board attended by a member of the Department of Health (e.g. Environmental Hazard Board).

SAHSU has a single s251 support in place to cover the above. Any project which may have additional requirements (for example to require the linkage of an additional dataset beyond that previously agreed) must seek an amendment to existing s251 and ethics approvals. It would also be outside the scope of this application, and therefore an amendment would be put before IGARD for consideration.

ONS NN4B (2006-2012)

SAHSU currently holds ONS NN4B data from the period 2006 to 2012 which have been used to link to the ONS birth registrations (live and stillbirth). SAHSU have HRA-CAG approval (Ref - 20/CAG/0028) and London - South East Research Ethics Committee approval (Ref: 17/LO/0846) to hold and link ONS Birth registrations to NN4B data. SAHSU has not been able to get more up to date NN4B data from ONS, as of 2015 NN4B has been replaced with the Personal Demographics Service and is now managed by NHS Digital.

The gestational age and ethnicity information from NN4B were added to ONS birth registration data to create an enhanced dataset for use in SAHSU research.

The gestational age information is useful for SAHSU research for the following reasons:

1) gestational age is needed to correctly define low birth weight data some babies have a low birth weight due to being born early rather than any actual growth retardation;

2) to more accurately define trimester/pregnancy-specific exposures by allowing a day of conception (i.e. the first day of potential exposure) to be calculated;

3) to define specific reproductive outcomes such as pre-term delivery. Adjustment for ethnicity is crucial in a range of studies and without individual-level data area-level measures of ethnicity must be used.

4) Evaluation of birth weight trends

5) Construction of Birth weight charts sex-specific and ethnic-specific

6) Validation of the existing birth weight charts and evaluation of the misclassification rates

7) Evaluation of stillbirths in relation to birth weight charts

This can be problematic as many reproductive outcomes are strongly linked to ethnicity, for example, birth weight varies amongst ethnic groups and without individual ethnicity information definitions and interpretation of low birth weight is less accurate.

The enhanced birth dataset (ONS birth registration + NN4B) and more up-to-date births data with gestational age information would allow for current trends in births weight and birth weight distributions to be investigated.

The NN4B/Birth Notification dataset is an invaluable dataset because it combines individual-level information on ethnicity and gestational age, which are both essential to being able to properly interpret birthweight – babies of ethnic minority groups and/or who are born earlier tend to weigh less. This is particularly important to know about and to be able to adjust for in statistical analyses in London, as there are high percentages of ethnic minority groups living in areas experiencing high aircraft noise exposure. This is important for this study, which is likely to influence policy on aircraft traffic.

SAHSU have previously evaluated ONS birth registration, HES and NN4B datasets (Ghosh RE, Ashworth DC, Hansell AL, Garwood K, Elliott P, Toledano MB. Routinely collected English birth data sets: comparisons and recommendations for reproductive epidemiology. Arch Dis Child Fetal Neonatal Ed. 2016 Sep;101(5):F451-7) and concluded that NN4B was the best dataset to use in epidemiological studies. Alternative datasets are not as good and may lead to biased estimates of any associations between noise and birth outcomes – ONS birth registrations do not have information on gestational age or ethnicity; HES data have issues with the completeness of both information and coverage.

Having national data will enable SAHSU to provide the ad-hoc rapid response to Public Health England, Department of Health and Social Care etc. Given that PHE's coverage is across England, and the requirements cannot be predicted in advance, national data is required given that response times do not permit time to request, receive and process individual extracts of data. Historical data is also essential for all projects to enable SAHSU to obtain longitudinal data on prior admissions for patients.

The following projects are on hold until the NN4B/Birth Notifications/Registrations data is made available to SAHSU.

1. Evaluation of birth weight trends:

Birth weight centiles updated with the data 2012-18 (up to the available year) and small for gestational age centiles to be used as a threshold to define small for gestational age (SGA) outcome in future environmental epidemiology studies

2. Evaluation of stillbirths in relation to birth weight charts:

Analysis of the effect of stillbirths in relation to Birth weight centiles.

3. Construction of Birth weight charts sex-specific and ethnic-specific:

Birth weight trends to investigate the evolution of trends in England and Wales, (including data from 1986-2012) and to identify change points and analysis in the relation of ethical differences.

4. Validation of the existing birth weight charts and evaluation of the misclassification rates:

Validation of the actual birth weight chart with the most recent data, to investigate based on the birth weight trends if updated are required due to changes in population distribution

The following projects will commence once the NN4B/Birth Notifications/Registrations data is made available to SAHSU:

Public Health Impacts of Clean Air Zones: This MRC funded study will explore the health impacts of the London Ultra Low Emission Zone (ULEZ). The ULEZ is predicted to positively impact health outcomes by reducing the exposure of residents living within the ULEX to traffic-related air pollution. This project aims to measure the health impacts (including low birth weight) and assess whether the health impacts differ depending on demographic or socio-economic factors. The findings will inform local and national policy on clean air zones.

Pathways to equitable health in cities: This Wellcome Trust funded study aims to understand the impacts of planning and policy actions on the social, natural and build environment on population health (including preterm birth and low birth weight) and health inequalities. The study will directly inform actions that influence people’s health. In London, the study will collaborate with the Greater London Authority and Public Health England.

The GDPR lawful basis for SAHSU to process this data is Article 6(1)(e) 'task in the public interest' and Article 9(2)(j) 'scientific or historical research purposes or statistical purposes'.

This Agreement permits the secure retention of the data only and no other processing.

No new outputs will be produced under this Data Sharing Agreement.

SAHSU's proposed work will continue with the same themes of SAHSU’s programme of work agreed with Public Health England. Some examples of SAHSU's studies that have previously required ONS Birth registration data linked to NN4B/Birth Notification data are:

Incinerators:

This is a national study of birth outcomes near Municipal Waste Incinerators during 2003-10 (http://www.sahsu.org/content/incinerators-study) that investigated the following questions: Are the emissions from incinerators required to operate under the standards set by the EU Waste Incineration Directive (WID) (2000/76/EC) linked with adverse reproductive and infant health outcomes? Is living near a municipal waste incinerator (MWI) linked with adverse reproductive and infant health outcomes? The study was commissioned to extend the evidence base and to provide further information to the public about any potential reproductive and infant health risks from MWIs and to extend the evidence base with respect to exposures and any potential reproductive and infant health risks from MWIs.

Maternal residential exposure to aircraft and railway noise and risks of adverse birth outcomes:

The study investigated whether there is an impact of aircraft noise exposure from Heathrow airport on the birth weight of babies living near the airport. There is good biological plausibility through noise-induced stress and also the known associations of environmental noise on blood pressure that may affect blood flow to the placenta. The analysis follows on from the SAHSU ‘Traffic in London’ study recently published in the BMJ (Smith RB, Fecht D, Gulliver J, Beevers SD, Dajnak D, Blangiardo M, Ghosh RE, Hansell AL, Kelly FJ, Anderson HR, Toledano MB. Impact of London's road traffic air and noise pollution on birth weight: retrospective population-based cohort study. BMJ. 2017 Dec 5;359:j5299), which examined road traffic noise using the NN4B dataset. The study suggested potential impacts at the highest levels of road traffic noise exposure. The impact of aircraft noise on birth weight are important to assess, as aircraft noise exposures are higher in some areas than road traffic noise and that the quality of the noise of an aircraft flying overhead means that noise is more intrusive, also in London aircraft overfly heavily populated areas.

Green Space and Birth Outcomes:

The availability of green space has been linked to multiple health benefits, with recent studies in the USA and Europe suggesting a link between improved birth outcomes and residential exposure to green space. The aim of this SAHSU study was to explore the associations between green space and birth outcomes in London.

Traffic pollution and health in London:

This MRC centre study aims to describe and understand the patterns of exposure of the population in London to traffic pollution (including air and noise) and their relationships to health (http://www.kcl.ac.uk/lsm/research/divisions/aes/research/ERG/research-projects/traffic/index.aspx). The consortium of over 20 investigators has a wide range of work packages. SAHSU related deliverables are to quantify relationships between traffic noise and air pollution and the following health outcomes: mortality, hospital admissions and adverse birth outcomes including low birth weight in the study period 2003-10.

Air pollution data came from the Environmental Research Group at Kings College and noise exposures have been modelled at Imperial. ONS birth registrations are linked with NN4B data to generate an enhanced and added-value ONS birth dataset with gestation age and ethnicity which is important for accurate exposure estimation and outcome interpretation. Maternal residential addresses at the time of birth are used in order to accurately estimate exposures at residential addresses.

Small for gestational age (SGA):

Small for gestational age (SGA) is normally defined as a baby with a weight below the 10th percentile for their sex and gestational age. Defining the gender-specific birth weight for gestational age can be done in two ways, 1) a within study distribution or; 2) using pre-defined centile charts based on other studies. The main pre-defined reference curves currently in use in the UK are based on the British 1990 (UK90) reference which is based on measurements from white British children born between 1983 and 1994. Additional ethnic-specific centile charts have since been produced. A recent study investigated whether the UK90 centile charts predicted neonatal outcomes better than an ethnic-specific one using data from 9102 births in the Born in Bradford cohort. This project uses national data for the whole of England and Wales (2006-2014) to calculate national centile charts, including ethnic-specific centile charts. These are used to calculate the risk of being SGA as compared to using the UK90 and ethnic-specific centile charts.

Smoking ban:

This study examined the impact of the smoke-free legislation on rates of preterm birth, low birth weight (LBW) and small for gestational age (SGA). As a consequence of the Health Act 2006, England successfully implemented comprehensive smoke-free legislation in July 2007, prohibiting smoking in all enclosed or partially enclosed public spaces. Few studies have examined the impact of interventions to reduce exposure to second-hand smoke on pregnancy outcomes.

This Agreement permits the secure retention of the data only and no other processing

Examples of how outputs from SAHSU’s studies are being used to inform health policy include:

Smoking ban:

This study examined the impact of the smoke-free legislation on rates of preterm birth, low birth weight (LBW) and small for gestational age (SGA). As a consequence of the Health Act 2006, England successfully implemented comprehensive smoke-free legislation in July 2007, prohibiting smoking in all enclosed or partially enclosed public spaces. Few studies have examined the impact of interventions to reduce exposure to second-hand smoke on pregnancy outcomes.

Protective effects of smoke-free legislation on birth outcomes in England - a regression discontinuity design. Bakolis, Ioannis; Kelly, Ruth; Fecht, Daniela; Best, Nicky; Millett, Christopher; Garwood, Kevin; Elliott, Paul; Hansell, Anna L; Hodgson, Susan. Published ahead of print - doi: 10.1097/EDE.0000000000000534 available http://journals.lww.com/epidem/Abstract/publishahead/Protective_effects_of_smoke_free_legislation_on.98989.aspx

Susan Hodgson ‘video abstract’ on this paper is available here: https://journals.lww.com/epidem/Pages/videogallery.aspx?videoId=33&autoPlay=true

Posters presentations:

Poster (Regression discontinuity design and policy evaluation: an evaluation of smoke-free legislation on birth outcomes. Ioannis Bakolis, Ruth Kelly, Daniela Fecht, Nicky Best, Anna Hansell, Christopher Millett, Kevin Garwood and Susan Hodgson) - 8th UK and Ireland Occupational & Environmental Epidemiology Meeting, London, April 2014

Poster (Smoke-Free Legislation and Adverse Pregnancy Outcomes in England

Ioannis Bakolis, Ruth Kelly, Daniela Fecht, Nicky Best, Anna Hansell, Christopher Millett, Kevin Garwood, Paul Elliot , Susan Hodgson) International Society of Environmental Epidemiology, Seattle, Washington, August 2014

Poster (Regression Discontinuity Design and Policy Evaluation: an Evaluation of Smoke-Free Legislation on Adverse Pregnancy Outcomes Ioannis Bakolis, Nicky Best, Daniela Fecht, Anna Hansell, Christopher Millett, Paul Elliot, Kevin Garwood, Ruth Kelly, Susan Hodgson, International Society of Environmental Epidemiology, Seattle, Washington, August 2014

The results of SAHSU studies are placed in the public domain via peer-reviewed publications and presenting results at scientific meetings and conferences and are used to inform the behaviour of health care providers and to inform national public health policy. To reach relevant stakeholders, SAHSU puts out press releases in collaboration with the Imperial College Press Office and holds press conferences, where relevant (e.g. as part of the re-launch of the SAHSU Environment and Health Atlas for England and Wales). All studies equally feedback their results into the relevant policy leads within PHE and PHE is informed of any outputs ahead of publication.

Where results are likely to be of particular interest, SAHSU puts out a press release and, if necessary, hold a press conference e.g. for the SAHSU Environment and Health Atlas for England and Wales published in 2014, SAHSU held a press conference and several media interviews, including the Assistant Director of SAHSU being interviewed on the BBC Radio 4 Today programme. SAHSU also respond to media enquiries relevant to SAHSU’s work e.g. the former Assistant Director of SAHSU took part in a Newsnight report on health effects of air pollution, broadcast 17 October 2016.SAHSU also present its work at scientific advisory committees where of particular national interest e.g. some of SAHSU's work on the incinerators project was considered during meetings of the Committee on Carcinogenicity (COC) and the Committee on Toxicity of Chemicals in foods, consumer products and the environment (COT).

SAHSU puts details of its research on the SAHSU website (http://www.imperial.ac.uk/school-public-health/epidemiology-and-biostatistics/small-area-health-statistics-unit/), including publications and outputs. For the SAHSU Environment and Health Atlas for England and Wales, SAHSU developed a public-facing website with interactive searchable maps and explanatory text (www.envhealthatlas.co.uk) working with the NGO Sense About Science.

SAHSU takes part in a wide range of public-facing events, both general and project-specific For example, in June 2016, members of SAHSU presented work at the ‘Life Bank- Interactive Science Event’ as part of MRC Festival of Medical Research which targeted young members of the public aged 18-40 years old, including on the Environment and Health Atlas for England and Wales (involving nine cancer outcomes mapped at small area level across England and Wales), bioaerosols and health effects of environmental noise. See video at https://www.youtube.com/watch?v=ml4XyHs720I - A look at how your environment affects your health at the MRC festival.

SAHSU will continue to present and seek feedback on work and also approaches to data handling to the MRC Centre Public and Community Oversight Group. In addition, also meets with various community organisations and provides research updates and meetings with government departments.

In 2017, 2018 and 2019, members of SAHSU presented work at Imperial Festival, the university’s annual public engagement showcase. In 2017, SAHSU members contributed to exhibits on both the health benefits of green space and more generally on the health effects of environmental pollutants such as air pollution and noise. In 2018, the Centre for Environment and Health organised exhibits on both exposomics, and more specifically on work related to SAHSU in an exhibit entitled “Big data, small areas”, which involved demonstrating the Environment and Health Atlas for England and Wales, outlining how SAHSU uses routine health and environmental data and also covering noise and air pollution in London. In 2019 SAHSU presented an art installation on the perception of urban green space.

The Centre for Environment and Health and the Health Protection Research Units (Environmental Exposures and Health HPRU and Chemical and Radiation Threats and Hazards HPRU) have a joint public and community advisory group.

This agreement permits Imperial College London to continue to hold the NN4B data disseminated by ONS, but not to otherwise process it. The remainder of the wording in this Objective for Processing section relates to processing established under the last approved agreement V0.6

The Small Area Health Statistics Unit (SAHSU) is a long-standing and internationally-recognised centre of excellence assessing the risk of exposure to environmental pollutants to the health of the population, with an emphasis on the use and interpretation of routine health statistics at small-area level. SAHSU was established in 1987 as a recommendation of the Black enquiry into the incidence of leukaemia and lymphoma in children and young adults near the Windscale/Sellafield nuclear power plant. SAHSU has a particular role nationally in carrying out environmental health surveillance of the population in relation to environmental contaminants and point sources of industrial pollution, based on routinely collected health data. This is a highly specialised area of work requiring excellence in computing, database management, geographical information systems (GIS), statistics, environmental exposure assessment and epidemiology. The set of skills and expertise that has been established and built up in SAHSU is a unique resource both nationally and worldwide.

SAHSU holds comprehensive computerised sets of health and demographic data and a range of environmental datasets at high spatial resolution.

SAHSU is funded by Public Health England (PHE) to contribute to public health in the UK. SAHSU has a programme of work established which is defined by the following terms of reference: -

• Developing and maintaining databases of health data, environmental exposures as required to meet specific need, also of social confounding factors at a small-area level

• Carrying out substantive research studies on environment and health issues

• Working in collaboration with other scientific groups, to build up reliable background information on the distribution of environmental exposure, socio-economic data and disease amongst small areas

• Acting as a centre of expertise, disseminating information on developments in spatial epidemiological methods to regional, national and international groups

• Responding rapidly, with expert advice, to ad hoc queries from the core funding bodies (Department of Health and Public Health England) about unusual clusters of disease, particularly in the neighbourhood of industrial installations

To deliver against the Terms of Reference, SAHSU utilises the research database to meet the following purposes:

Purpose 1 - Maintenance of the SAHSU health research database

At the core of the overall programme of work is the maintenance of the SAHSU research database, which combines multiple datasets and has both ethics and s251 approvals in place. A particular strength is the maintenance of historic data, which allows SAHSU to examine long term trends and use of data at high spatial resolution (address and postcode), which are crucial for studies of environmental exposures determined by spatial location e.g. electromagnetic field exposure arising from proximity to an overhead power line.

Purpose 2 - To carry out a programme of research projects and studies

The research programme includes both methods development and investigation of priority questions in environment and health. A key aim is to improve the science base underlying translation of knowledge on the effects of the environment on health into policy. SAHSU conducts national research studies on environmental factors that may affect health ranging from exposures to e.g. electromagnetic fields (such as from mobile phone base stations), traffic-related air pollution, road and aircraft noise, water contaminants, waste disposal, using nationally collected patient data including mortality, hospital admissions, cancer registrations and births data. Additional small-area analyses are conducted that help support the general remit of the unit e.g. investigating differential hospital admission rates in ethnically diverse neighbourhoods. SAHSU provides national expertise in cluster detection and small-area statistical methods and has close links with Public Health England including input into PHE's environmental public health tracking programme and surveillance activities.

Purpose 3 - To build up reliable background information on the distribution of environmental exposures, socioeconomic data and disease amongst small areas

SAHSU have developed an extensive collection of environmental exposure data e.g. air pollution, magnetic fields, environmental noise, that SAHSU hold at high spatial resolution, together with geographically-referenced health data as needed in approved studies - all SAHSU studies are controlled via the PHE-SAHSU Liaison Committee. An example of this work is the Environment and Health Atlas for England and Wales, which included 14 conditions (nine cancers) at small area level (website http://www.envhealthatlas.co.uk/homepage/ and OUP book: Hansell AL, Beale LA, Ghosh RE, Fortunato L, Fecht D, Järup L, Elliott P. The Environment and Health Atlas for England and Wales. Oxford University Press, April 2014, Oxford, UK.).

Purpose 4 - To develop methodology for analysing and interpreting health outcomes related to small areas

Some of SAHSU's studies are methodological, relating to for example, statistical uncertainty in observed health risks in areas relating to choice of spatial boundaries or uncertainties in the population estimates; development of methods to detect clusters of disease in time and space (surveillance); development of methods to better adjust for lifestyle factors in health risk analyses by using risk scores constructed at area-level from cohort datasets and surveys in SAHSU's analyses of hospital admissions and mortality.

Purpose 5 - To act as a centre of expertise, disseminating information on developments in spatial epidemiological methods to national and regional groups

SAHSU participate in national and international scientific meetings and provide training to PHE and internationally including to the US Centers for Disease Control (CDC) in use of small area analysis for public health purposes. SAHSU use aggregate non-disclosive data in outputs, presentations and training.

Purpose 6 - To provide rapid ad hoc support to PHE and DH about unusual clusters of disease, particularly in the neighbourhood of industrial installations

Such work is carried out on the instruction of Department of Health or Public Health England, and is approved by the Director of SAHSU. By its nature, such requirements cannot be detailed in advance, but the only outputs would be aggregate with small numbers suppressed, and provided to DH and PHE.

Approval of projects

PHE's representation on the PHE-SAHSU Liaison Committee is to provide oversight of the use of the PHE funding ensuring that it is being used within the remit of the funding agreement. Most SAHSU studies are funded through peer-reviewed grants from research councils such as UKRI, NIHR and the Wellcome Trust and other charities e.g. the Cystic Fibrosis Trust. Even though, PHE provides the core infrastructure funding for SAHSU, they do not have any decision making responsibilities over the project initiations within the SAHSU unit.

Project/study initiations are done by researchers within SAHSU. All new studies using SAHSU data must be approved as a "SAHSU-study". To do so, researchers have to provide a project outline detailing the project rational, its relevance to patients and the public (i.e. health and/or social care) and which data will be required. The study can then be approved by either the Director or Assistant Director of SAHSU under consideration of SAHSU's overall programme terms of reference and whether the study is adequately covered by SAHSU's existing ethical approval and if not, separate ethical approval must be sought.

Once approved internally, the project is introduced to PHE via the PHE-SAHSU Liaison Committee which will provide confirmation that the project falls within the PHE-SAHSU funding remit and will then be forwarded to get formal minuted approval from the appropriate PHE programme board attended by a member of the Department of Health (e.g. Environmental Hazard Board).

SAHSU have a single s251 support in place to cover the above. Any project which may have additional requirements (for example to require the linkage of an additional dataset beyond that previously agreed) must seek an amendment to existing s251 and ethics approvals. It would also be outside the scope of this application, and therefore an amendment would be put before IGARD for consideration.

ONS NN4B (2006-2012)

SAHSU currently hold ONS NN4B data from period 2006 to 2012 which have been used to link to the ONS birth registrations (live and still birth). SAHSU have HRA-CAG approval (Ref - 14/CAG/1039) and London - South East Research Ethics Committee approval (Ref: 17/LO/0846) to hold and link ONS Birth registrations to NN4B data. SAHSU have not been able to get more up to date NN4B data from ONS, as of 2015 NN4B has been replaced with the Personal Demographics Service and now held by NHS Digital.

The gestational age and ethnicity information from NN4B were added to ONS birth registration data to create an enhanced dataset for use in SAHSU research.

The gestational age information is useful for SAHSU research for the following reasons:

1) gestational age is needed to correctly define low birth weight data some babies have low birth weight due to being born early rather than any actual growth retardation;

2) to more accurately define trimester/pregnancy specific exposures by allowing a day of conception (i.e. the first day of potential exposure) to be calculated;

3) to define specific reproductive outcomes such as pre-term delivery. Adjustment for ethnicity is crucial in a range of studies and without individual level data area-level measures of ethnicity must be used.

4) Evaluation of birth weight trends

5) Construction of Birth weight charts sex-specific and ethnic-specific

6) Validation of the existing birth weight charts and evaluation of the misclassification rates

7) Evaluation of stillbirths in relation to birth weight charts

This can be problematic as many reproductive outcomes are strongly linked to ethnicity, for example birth weight varies amongst ethnic groups and without individual ethnicity information definitions and interpretation of low birth weight is less accurate.

The enhanced birth dataset (ONS birth registration + NN4B) has and will enable SAHSU to fulfil its remits to respond rapidly to queries about unusual clusters of disease; to carry out substantive research studies on environment and health issues; to develop and maintain databases of health data, environmental exposures and confounding socio-economic factors as required to fulfil these aims; and to develop methodology for use in small area studies. For example, up-to-date births data with gestational age information would allow for current trends in births weight and birth weight distributions to be investigated.

The NN4B dataset is an invaluable dataset because it combines individual-level information on ethnicity and gestational age, which are both essential to be able to properly interpret birthweight – babies of ethnic minority groups and/or who are born earlier tend to weigh less. This is particularly important to know about and to be able to adjust for in statistical analyses in London, as there are high percentages of ethnic minority groups living in areas experiencing high aircraft noise exposure. This is important for this study, which is likely to influence policy on aircraft traffic.

SAHSU have previously evaluated ONS birth registration, HES and NN4B datasets (Ghosh RE, Ashworth DC, Hansell AL, Garwood K, Elliott P, Toledano MB. Routinely collected English birth data sets: comparisons and recommendations for reproductive epidemiology. Arch Dis Child Fetal Neonatal Ed. 2016 Sep;101(5):F451-7) and concluded that NN4B was the best dataset to use in epidemiological studies. Alternative datasets are not as good and may lead to biased estimates of any associations between noise and birth outcomes – ONS birth registrations do not have information on gestational age or ethnicity; HES data have issues with completeness of both information and coverage.

SAHSU has a particular role nationally in carrying out environmental health surveillance of the population in relation to environmental contaminants and point sources of industrial pollution, based on routinely collected health data. Having national data will enable SAHSU to provide the ad-hoc rapid response to Public Health England. Given that PHE coverage is across England, and the requirements cannot be predicted in advance, national data is required given that response times do not permit time to request, receive and process individual extracts of data. Historical data is also essential for all projects to enable SAHSU to obtain longitudinal data on prior admissions for patients.

The GDPR lawful basis for SAHSU to process this data is Article 6(1)(e) 'task in the public interest' and Article 9(2)(j) 'scientific or historical research purposes or statistical purposes'.

SAHSU's proposed work will continue with the same themes of SAHSU’s programme of work agreed with Public Health England.

Some of SAHSU’s studies for which ONS Birth registration linked to NN4B data are required:

Maternal residential exposure to aircraft and railway noise and risks of adverse birth outcomes: (on-going)

The study aims to investigate whether there is an impact of aircraft noise exposure from Heathrow airport on birthweight of babies living near the airport. There is good biological plausibility through noise-induced stress and also the known associations of environmental noise on blood pressure that may affect blood flow to the placenta. The analysis follows on from the SAHSU ‘Traffic in London’ study recently published in the BMJ (Smith RB, Fecht D, Gulliver J, Beevers SD, Dajnak D, Blangiardo M, Ghosh RE, Hansell AL, Kelly FJ, Anderson HR, Toledano MB. Impact of London's road traffic air and noise pollution on birth weight: retrospective population-based cohort study. BMJ. 2017 Dec 5;359:j5299), which examined road traffic noise using the NN4B dataset. The study suggested potential impacts at highest levels of road traffic noise exposure. The impact of aircraft noise on birthweight are important to assess, as aircraft noise exposures are higher in some areas than road traffic noise and that the quality of the noise of an aircraft flying overhead means that noise is more intrusive, also in London aircraft overfly heavily populated areas.

Green Space and Birth Outcomes (on-going)

The availability of green space has been linked to multiple health benefits, with recent studies in the USA and Europe suggesting a link between improved birth outcomes and residential exposure to green space. The aim of this SAHSU study is to explore the associations between green space and birth outcomes in London.

The ONS NN4B dataset for 2006-2012, provides information on approximately 700,000 births per year across England. Outcomes of interest include: 1) birth weight; 2) gestational age at delivery; and 3) small for gestational age 4) preterm delivery, all leading causes of perinatal mortality and morbidity, and associated with increased morbidity in later life. Maternal address at delivery will be linked to relevant measures of green space exposure/access using LiDAR data on ground cover vegetation and trees for Greater London and OS MaterMap.

The impact of potentially confounding variables, including maternal age, parity and air pollution, as well as area-level socio-economic deprivation and smoking will be explored.

Traffic in London: (on-going)

The objectives of this study are to investigate population exposures in London to traffic pollution (including air and noise) and relationships with health, including examining traffic-related air pollution, aircraft noise and road noise in relation to adverse birth outcomes such as low birth weight.

This MRC-PHE centre study lead by Kings College London aims to describe and understand the patterns of exposure of the population in London to traffic pollution (including air and noise) and their relationships to health (http://www.kcl.ac.uk/lsm/research/divisions/aes/research/ERG/research-projects/traffic/index.aspx). The consortium of over 20 investigators has a wide range of work packages. SAHSU related deliverables are to quantify relationships between traffic noise and air pollution and the following health outcomes: mortality, hospital admissions and adverse birth outcomes including low birth weight in the study period 2003-10.

Air pollution data come from the Environmental Research Group at Kings College and noise exposures have been modelled at Imperial. ONS birth registrations are linked with NN4B data to generate an enhanced and added-value ONS birth dataset with gestation age and ethnicity which is important for accurate exposure estimation and outcome interpretation. Postcodes are used in order to accurately estimate exposures at residential address.

Incinerators: (on-going)

This national study investigates whether emissions from solid municipal waste incinerators (MSWis) in operation after implementation of the EU Waste Incineration Directive (WID) (2000176/EC) pose a risk to reproductive and infant health. Modelled ground level concentrations of emissions from 22 MSWis in 2003-2010 will be investigated in relation to birth weight low/very low birth weight, preterm delivery, stillbirths and small for gestation age.

Small for gestational age (SGA): on-going

Small for gestational age (SGA) is normally defined as a baby with a weight below the 10th percentile for their sex and gestational age. Defining the gender-specific birth weight for gestational age can be done in two ways, 1) a within study distribution or; 2) using pre-defined centile charts based on other studies. The main pre-defined reference curves currently in use in the UK are based on the British 1990 (UK90) reference which is based on measurements from white British children born between 1983 and 1994. Additional ethnic specific centile charts have since been produced. A recent study investigated whether the UK90 centile charts predicted neonatal outcomes better than an ethnic-specific one using data from 9102 births in the Born in Bradford cohort. This project will use national data for the whole of England and Wales (2006-2014) to calculate national centile charts, including ethnic-specific centile charts. These will be used to calculate the risk of being SGA as compared to using the UK90 and ethnic specific centile charts.

Other projects that will require NN4B data are:

1. Evaluation of birth weight trends:

2. Evaluation of stillbirths in relation to birth weight charts:

3. Construction of Birth weight charts sex-specific and ethnic-specific:

4. Validation of the existing birth weight charts and evaluation of the misclassification rates:

Smoking ban:

This study examined the impact of the smoke-free legislation on rates of preterm birth, low birth weight (LBW) and small for gestational age (SGA). As a consequence of the Health Act 2006, England successfully implemented comprehensive smoke-free legislation in July 2007, prohibiting smoking in all enclosed or partially enclosed public spaces. Few studies have examined impact of interventions to reduce exposure to second-hand smoke on pregnancy outcomes.

Smoking ban:

This study examined the impact of the smoke-free legislation on rates of preterm birth, low birth weight (LBW) and small for gestational age (SGA). As a consequence of the Health Act 2006, England successfully implemented comprehensive smoke-free legislation in July 2007, prohibiting smoking in all enclosed or partially enclosed public spaces. Few studies have examined impact of interventions to reduce exposure to second-hand smoke on pregnancy outcomes.

Protective effects of smoke-free legislation on birth outcomes in England - a regression discontinuity design. Bakolis, Ioannis; Kelly, Ruth; Fecht, Daniela; Best, Nicky; Millett, Christopher; Garwood, Kevin; Elliott, Paul; Hansell, Anna L; Hodgson, Susan. Published ahead of print - doi: 10.1097/EDE.0000000000000534 available http://journals.lww.com/epidem/Abstract/publishahead/Protective_effects_of_smoke_free_legislation_on.98989.aspx

Also Susan Hodgson ‘video abstract’ on this paper available here: https://journals.lww.com/epidem/Pages/videogallery.aspx?videoId=33&autoPlay=true

Posters presentations:

Poster (Regression discontinuity design and policy evaluation: an evaluation of smoke free

legislation on birth outcomes. Ioannis Bakolis, Ruth Kelly, Daniela Fecht, Nicky Best, Anna Hansell, Christopher Millett, Kevin Garwood and Susan Hodgson) - 8th UK and Ireland Occupational & Environmental Epidemiology Meeting, London, April 2014

Poster (Smoke-Free Legislation and Adverse Pregnancy Outcomes in England

Ioannis Bakolis, Ruth Kelly, Daniela Fecht, Nicky Best, Anna Hansell, Christopher Millett, Kevin Garwood, Paul Elliot , Susan Hodgson) International Society of Environmental Epidemiology, Seattle, Washington, August 2014

Poster (Regression Discontinuity Design and Policy Evaluation: an Evaluation of Smoke Free Legislation on Adverse Pregnancy Outcomes Ioannis Bakolis, Nicky Best, Daniela Fecht, Anna Hansell, Christopher Millett, Paul Elliot, Kevin Garwood, Ruth Kelly, Susan Hodgson, International Society of Environmental Epidemiology, Seattle, Washington, August 2014

SAHSU has a long record of publishing its research in high quality peer reviewed journals and presenting results at scientific meetings and conferences to inform policy and to empower public debate. SAHSU puts details of its research on its website (http://www.imperial.ac.uk/school-public-health/epidemiology-and-biostatistics/small-area-health-statistics-unit/), including publications and outputs.

Where results are likely to be of particular interest, SAHSU put out a press release and, if necessary, hold a press conference e.g. for the SAHSU Environment and Health Atlas for England and Wales published in 2014, SAHSU held a press conference and several media interviews, including the Assistant Director of SAHSU being interviewed on the BBC Radio 4 Today programme. SAHSU also respond to media enquiries relevant to SAHSU’s work e.g. the Assistant Director of SAHSU took part in a Newsnight report on health effects of air pollution, broadcast 17 October 2016.SAHSU also present its work at scientific advisory committees where of particular national interest e.g. some of SAHSU's work on the incinerators project will be considered at forthcoming meetings of the Committee on Carcinogenicity (COC) and the Committee on Toxicity of chemicals in foods, consumer products and the environment (COT).

SAHSU puts details of its research on the SAHSU website (http://www.imperial.ac.uk/school-public-health/epidemiology-and-biostatistics/small-area-health-statistics-unit/), including publications and outputs. For the SAHSU Environment and Health Atlas for England and Wales, SAHSU developed a public-facing website with interactive searchable maps and explanatory text (www.envhealthatlas.co.uk) working with the NGO Sense About Science.

SAHSU take part in a wide range of public facing events, both general and project specific For example, in June 2016, members of SAHSU presented work at the ‘Life Bank- Interactive Science Event’ as part of MRC Festival of Medical Research which targeted young members of the public aged 18-40 years old, including on the Environment and Health Atlas for England and Wales (involving nine cancer outcomes mapped at small area level across England and Wales), bioaerosols and health effects of environmental noise. See video at https://www.youtube.com/watch?v=ml4XyHs720I - A look at how your environment affects your health at the MRC festival.

SAHSU present work and also approaches to data handling to the MRC-PHE Centre for Environment and Health Community Advisory Board. In addition to meetings with the MRC-PHE Centre Community Advisory Board, SAHSU also meet with various community organisations e.g. the assistant director attends noise committee meetings of Environmental Protection UK and provides research updates and meetings with government departments.

SAHSU also present its work at scientific advisory committees where of particular national interest. Besides details of SAHSU research can be accessed via its website http://www.imperial.ac.uk/school-public-health/epidemiology-and-biostatistics/small-area-health-statistics-unit/), including publications and outputs, SAHSU's Environment and Health Atlas for England and Wales, SAHSU developed a public-facing website with interactive searchable maps and explanatory text (www.envhealthatlas.co.uk) working with the NGO Sense About Science. Policy makers.

In 2015, SAHSU attended the launch of the Respiratory Health of the Nation project, which used respiratory hospital admission, mortality and cancer registrations data, at the House of Commons in July. This project presented SAHSU maps of the respiratory conditions. In January 2018, the Assistant Director presented information on SAHSU noise and health studies to the All Party Parliamentary Group on Heathrow Expansion.

In 2017 and 2018, members of SAHSU also presented work at Imperial Festival, the university’s annual public engagement showcase. In 2017, SAHSU members contributed to exhibits on both the health benefits of greenspace, and more generally on the health effects of environmental pollutants such as air pollution and noise. In 2018 the Centre for Environment and Health organised exhibits on both exposomics, and more specifically on work related to SAHSU in an exhibit entitled “Big data, small areas”, which involved demonstrating the Environment and Health Atlas for England and Wales, outlining how SAHSU uses routine health and environmental data, and also covering noise and air pollution in London. SAHSU members also took part in the MRC Festival of Medical Research in June 2017, in a public event for the community of Deptford demonstrating work on bioaerosols and health effects of environmental noise.

The Centre for Environment and Health and the Health Protection Research Unit in Health Impacts of Environmental Hazards have a joint community advisory board, a stakeholder group that provides input to research to and guidance on research projects – in 2017 SAHSU members have provided presentations on the estimation of costs to the NHS and social care due to the health impacts of air pollution, the use of personal data and noise as a public health problem.

This agreement permits Imperial College London to continue to hold the NN4B data disseminated by ONS, but not to otherwise process it. The remainder of the wording in this Objective for Processing section relates to processing established under the last approved agreement V0.6

The Small Area Health Statistics Unit (SAHSU) is a long-standing and internationally-recognised centre of excellence assessing the risk of exposure to environmental pollutants to the health of the population, with an emphasis on the use and interpretation of routine health statistics at small-area level. SAHSU was established in 1987 as a recommendation of the Black enquiry into the incidence of leukaemia and lymphoma in children and young adults near the Windscale/Sellafield nuclear power plant. SAHSU has a particular role nationally in carrying out environmental health surveillance of the population in relation to environmental contaminants and point sources of industrial pollution, based on routinely collected health data. This is a highly specialised area of work requiring excellence in computing, database management, geographical information systems (GIS), statistics, environmental exposure assessment and epidemiology. The set of skills and expertise that has been established and built up in SAHSU is a unique resource both nationally and worldwide.

SAHSU holds comprehensive computerised sets of health and demographic data and a range of environmental datasets at high spatial resolution.

SAHSU is funded by Public Health England (PHE) to contribute to public health in the UK. SAHSU has a programme of work established which is defined by the following terms of reference: -

• Developing and maintaining databases of health data, environmental exposures as required to meet specific need, also of social confounding factors at a small-area level

• Carrying out substantive research studies on environment and health issues

• Working in collaboration with other scientific groups, to build up reliable background information on the distribution of environmental exposure, socio-economic data and disease amongst small areas

• Acting as a centre of expertise, disseminating information on developments in spatial epidemiological methods to regional, national and international groups

• Responding rapidly, with expert advice, to ad hoc queries from the core funding bodies (Department of Health and Public Health England) about unusual clusters of disease, particularly in the neighbourhood of industrial installations

To deliver against the Terms of Reference, SAHSU utilises the research database to meet the following purposes:

Purpose 1 - Maintenance of the SAHSU health research database

At the core of the overall programme of work is the maintenance of the SAHSU research database, which combines multiple datasets and has both ethics and s251 approvals in place. A particular strength is the maintenance of historic data, which allows SAHSU to examine long term trends and use of data at high spatial resolution (address and postcode), which are crucial for studies of environmental exposures determined by spatial location e.g. electromagnetic field exposure arising from proximity to an overhead power line.

Purpose 2 - To carry out a programme of research projects and studies

The research programme includes both methods development and investigation of priority questions in environment and health. A key aim is to improve the science base underlying translation of knowledge on the effects of the environment on health into policy. SAHSU conducts national research studies on environmental factors that may affect health ranging from exposures to e.g. electromagnetic fields (such as from mobile phone base stations), traffic-related air pollution, road and aircraft noise, water contaminants, waste disposal, using nationally collected patient data including mortality, hospital admissions, cancer registrations and births data. Additional small-area analyses are conducted that help support the general remit of the unit e.g. investigating differential hospital admission rates in ethnically diverse neighbourhoods. SAHSU provides national expertise in cluster detection and small-area statistical methods and has close links with Public Health England including input into PHE's environmental public health tracking programme and surveillance activities.

Purpose 3 - To build up reliable background information on the distribution of environmental exposures, socioeconomic data and disease amongst small areas

SAHSU have developed an extensive collection of environmental exposure data e.g. air pollution, magnetic fields, environmental noise, that SAHSU hold at high spatial resolution, together with geographically-referenced health data as needed in approved studies - all SAHSU studies are controlled via the PHE-SAHSU Liaison Committee. An example of this work is the Environment and Health Atlas for England and Wales, which included 14 conditions (nine cancers) at small area level (website http://www.envhealthatlas.co.uk/homepage/ and OUP book: Hansell AL, Beale LA, Ghosh RE, Fortunato L, Fecht D, Järup L, Elliott P. The Environment and Health Atlas for England and Wales. Oxford University Press, April 2014, Oxford, UK.).

Purpose 4 - To develop methodology for analysing and interpreting health outcomes related to small areas

Some of SAHSU's studies are methodological, relating to for example, statistical uncertainty in observed health risks in areas relating to choice of spatial boundaries or uncertainties in the population estimates; development of methods to detect clusters of disease in time and space (surveillance); development of methods to better adjust for lifestyle factors in health risk analyses by using risk scores constructed at area-level from cohort datasets and surveys in SAHSU's analyses of hospital admissions and mortality.

Purpose 5 - To act as a centre of expertise, disseminating information on developments in spatial epidemiological methods to national and regional groups

SAHSU participate in national and international scientific meetings and provide training to PHE and internationally including to the US Centers for Disease Control (CDC) in use of small area analysis for public health purposes. SAHSU use aggregate non-disclosive data in outputs, presentations and training.

Purpose 6 - To provide rapid ad hoc support to PHE and DH about unusual clusters of disease, particularly in the neighbourhood of industrial installations

Such work is carried out on the instruction of Department of Health or Public Health England, and is approved by the Director of SAHSU. By its nature, such requirements cannot be detailed in advance, but the only outputs would be aggregate with small numbers suppressed, and provided to DH and PHE.

Approval of projects

PHE's representation on the PHE-SAHSU Liaison Committee is to provide oversight of the use of the PHE funding ensuring that it is being used within the remit of the funding agreement. Most SAHSU studies are funded through peer-reviewed grants from research councils such as UKRI, NIHR and the Wellcome Trust and other charities e.g. the Cystic Fibrosis Trust. Even though, PHE provides the core infrastructure funding for SAHSU, they do not have any decision making responsibilities over the project initiations within the SAHSU unit.

Project/study initiations are done by researchers within SAHSU. All new studies using SAHSU data must be approved as a "SAHSU-study". To do so, researchers have to provide a project outline detailing the project rational, its relevance to patients and the public (i.e. health and/or social care) and which data will be required. The study can then be approved by either the Director or Assistant Director of SAHSU under consideration of SAHSU's overall programme terms of reference and whether the study is adequately covered by SAHSU's existing ethical approval and if not, separate ethical approval must be sought.

Once approved internally, the project is introduced to PHE via the PHE-SAHSU Liaison Committee which will provide confirmation that the project falls within the PHE-SAHSU funding remit and will then be forwarded to get formal minuted approval from the appropriate PHE programme board attended by a member of the Department of Health (e.g. Environmental Hazard Board).

SAHSU have a single s251 support in place to cover the above. Any project which may have additional requirements (for example to require the linkage of an additional dataset beyond that previously agreed) must seek an amendment to existing s251 and ethics approvals. It would also be outside the scope of this application, and therefore an amendment would be put before IGARD for consideration.

ONS NN4B (2006-2012)

SAHSU currently hold ONS NN4B data from period 2006 to 2012 which have been used to link to the ONS birth registrations (live and still birth). SAHSU have HRA-CAG approval (Ref - 14/CAG/1039) and London - South East Research Ethics Committee approval (Ref: 17/LO/0846) to hold and link ONS Birth registrations to NN4B data. SAHSU have not been able to get more up to date NN4B data from ONS, as of 2015 NN4B has been replaced with the Personal Demographics Service and now held by NHS Digital.

The gestational age and ethnicity information from NN4B were added to ONS birth registration data to create an enhanced dataset for use in SAHSU research.

The gestational age information is useful for SAHSU research for the following reasons:

1) gestational age is needed to correctly define low birth weight data some babies have low birth weight due to being born early rather than any actual growth retardation;

2) to more accurately define trimester/pregnancy specific exposures by allowing a day of conception (i.e. the first day of potential exposure) to be calculated;

3) to define specific reproductive outcomes such as pre-term delivery. Adjustment for ethnicity is crucial in a range of studies and without individual level data area-level measures of ethnicity must be used.

4) Evaluation of birth weight trends

5) Construction of Birth weight charts sex-specific and ethnic-specific

6) Validation of the existing birth weight charts and evaluation of the misclassification rates

7) Evaluation of stillbirths in relation to birth weight charts

This can be problematic as many reproductive outcomes are strongly linked to ethnicity, for example birth weight varies amongst ethnic groups and without individual ethnicity information definitions and interpretation of low birth weight is less accurate.

The enhanced birth dataset (ONS birth registration + NN4B) has and will enable SAHSU to fulfil its remits to respond rapidly to queries about unusual clusters of disease; to carry out substantive research studies on environment and health issues; to develop and maintain databases of health data, environmental exposures and confounding socio-economic factors as required to fulfil these aims; and to develop methodology for use in small area studies. For example, up-to-date births data with gestational age information would allow for current trends in births weight and birth weight distributions to be investigated.

The NN4B dataset is an invaluable dataset because it combines individual-level information on ethnicity and gestational age, which are both essential to be able to properly interpret birthweight – babies of ethnic minority groups and/or who are born earlier tend to weigh less. This is particularly important to know about and to be able to adjust for in statistical analyses in London, as there are high percentages of ethnic minority groups living in areas experiencing high aircraft noise exposure. This is important for this study, which is likely to influence policy on aircraft traffic.

SAHSU have previously evaluated ONS birth registration, HES and NN4B datasets (Ghosh RE, Ashworth DC, Hansell AL, Garwood K, Elliott P, Toledano MB. Routinely collected English birth data sets: comparisons and recommendations for reproductive epidemiology. Arch Dis Child Fetal Neonatal Ed. 2016 Sep;101(5):F451-7) and concluded that NN4B was the best dataset to use in epidemiological studies. Alternative datasets are not as good and may lead to biased estimates of any associations between noise and birth outcomes – ONS birth registrations do not have information on gestational age or ethnicity; HES data have issues with completeness of both information and coverage.

SAHSU has a particular role nationally in carrying out environmental health surveillance of the population in relation to environmental contaminants and point sources of industrial pollution, based on routinely collected health data. Having national data will enable SAHSU to provide the ad-hoc rapid response to Public Health England. Given that PHE coverage is across England, and the requirements cannot be predicted in advance, national data is required given that response times do not permit time to request, receive and process individual extracts of data. Historical data is also essential for all projects to enable SAHSU to obtain longitudinal data on prior admissions for patients.

The GDPR lawful basis for SAHSU to process this data is Article 6(1)(e) 'task in the public interest' and Article 9(2)(j) 'scientific or historical research purposes or statistical purposes'.

SAHSU's proposed work will continue with the same themes of SAHSU’s programme of work agreed with Public Health England.

Some of SAHSU’s studies for which ONS Birth registration linked to NN4B data are required:

Maternal residential exposure to aircraft and railway noise and risks of adverse birth outcomes: (2019)

The study aims to investigate whether there is an impact of aircraft noise exposure from Heathrow airport on birthweight of babies living near the airport. There is good biological plausibility through noise-induced stress and also the known associations of environmental noise on blood pressure that may affect blood flow to the placenta. The analysis follows on from the SAHSU ‘Traffic in London’ study recently published in the BMJ (Smith RB, Fecht D, Gulliver J, Beevers SD, Dajnak D, Blangiardo M, Ghosh RE, Hansell AL, Kelly FJ, Anderson HR, Toledano MB. Impact of London's road traffic air and noise pollution on birth weight: retrospective population-based cohort study. BMJ. 2017 Dec 5;359:j5299), which examined road traffic noise using the NN4B dataset. The study suggested potential impacts at highest levels of road traffic noise exposure. The impact of aircraft noise on birthweight are important to assess, as aircraft noise exposures are higher in some areas than road traffic noise and that the quality of the noise of an aircraft flying overhead means that noise is more intrusive, also in London aircraft overfly heavily populated areas.

Green Space and Birth Outcomes (on-going)

The availability of green space has been linked to multiple health benefits, with recent studies in the USA and Europe suggesting a link between improved birth outcomes and residential exposure to green space. The aim of this SAHSU study is to explore the associations between green space and birth outcomes in London.

The ONS NN4B dataset for 2006-2012, provides information on approximately 700,000 births per year across England. Outcomes of interest include: 1) birth weight; 2) gestational age at delivery; and 3) small for gestational age 4) preterm delivery, all leading causes of perinatal mortality and morbidity, and associated with increased morbidity in later life. Maternal address at delivery will be linked to relevant measures of green space exposure/access using LiDAR data on ground cover vegetation and trees for Greater London and OS MaterMap.

The impact of potentially confounding variables, including maternal age, parity and air pollution, as well as area-level socio-economic deprivation and smoking will be explored.

Traffic in London: (on-going)

The objectives of this study are to investigate population exposures in London to traffic pollution (including air and noise) and relationships with health, including examining traffic-related air pollution, aircraft noise and road noise in relation to adverse birth outcomes such as low birth weight.

This MRC-PHE centre study lead by Kings College London aims to describe and understand the patterns of exposure of the population in London to traffic pollution (including air and noise) and their relationships to health (http://www.kcl.ac.uk/lsm/research/divisions/aes/research/ERG/research-projects/traffic/index.aspx). The consortium of over 20 investigators has a wide range of work packages. SAHSU related deliverables are to quantify relationships between traffic noise and air pollution and the following health outcomes: mortality, hospital admissions and adverse birth outcomes including low birth weight in the study period 2003-10.

Air pollution data come from the Environmental Research Group at Kings College and noise exposures have been modelled at Imperial. ONS birth registrations are linked with NN4B data to generate an enhanced and added-value ONS birth dataset with gestation age and ethnicity which is important for accurate exposure estimation and outcome interpretation. Postcodes are used in order to accurately estimate exposures at residential address.

Incinerators: (on-going)

This national study investigates whether emissions from solid municipal waste incinerators (MSWis) in operation after implementation of the EU Waste Incineration Directive (WID) (2000176/EC) pose a risk to reproductive and infant health. Modelled ground level concentrations of emissions from 22 MSWis in 2003-2010 will be investigated in relation to birth weight low/very low birth weight, preterm delivery, stillbirths and small for gestation age.

Small for gestational age (SGA): on-going

Small for gestational age (SGA) is normally defined as a baby with a weight below the 10th percentile for their sex and gestational age. Defining the gender-specific birth weight for gestational age can be done in two ways, 1) a within study distribution or; 2) using pre-defined centile charts based on other studies. The main pre-defined reference curves currently in use in the UK are based on the British 1990 (UK90) reference which is based on measurements from white British children born between 1983 and 1994. Additional ethnic specific centile charts have since been produced. A recent study investigated whether the UK90 centile charts predicted neonatal outcomes better than an ethnic-specific one using data from 9102 births in the Born in Bradford cohort. This project will use national data for the whole of England and Wales (2006-2014) to calculate national centile charts, including ethnic-specific centile charts. These will be used to calculate the risk of being SGA as compared to using the UK90 and ethnic specific centile charts.

Other projects that will require NN4B data are:

1. Evaluation of birth weight trends:

2. Evaluation of stillbirths in relation to birth weight charts:

3. Construction of Birth weight charts sex-specific and ethnic-specific:

4. Validation of the existing birth weight charts and evaluation of the misclassification rates:

Smoking ban:

This study examined the impact of the smoke-free legislation on rates of preterm birth, low birth weight (LBW) and small for gestational age (SGA). As a consequence of the Health Act 2006, England successfully implemented comprehensive smoke-free legislation in July 2007, prohibiting smoking in all enclosed or partially enclosed public spaces. Few studies have examined impact of interventions to reduce exposure to second-hand smoke on pregnancy outcomes.

Smoking ban:

This study examined the impact of the smoke-free legislation on rates of preterm birth, low birth weight (LBW) and small for gestational age (SGA). As a consequence of the Health Act 2006, England successfully implemented comprehensive smoke-free legislation in July 2007, prohibiting smoking in all enclosed or partially enclosed public spaces. Few studies have examined impact of interventions to reduce exposure to second-hand smoke on pregnancy outcomes.

Protective effects of smoke-free legislation on birth outcomes in England - a regression discontinuity design. Bakolis, Ioannis; Kelly, Ruth; Fecht, Daniela; Best, Nicky; Millett, Christopher; Garwood, Kevin; Elliott, Paul; Hansell, Anna L; Hodgson, Susan. Published ahead of print - doi: 10.1097/EDE.0000000000000534 available http://journals.lww.com/epidem/Abstract/publishahead/Protective_effects_of_smoke_free_legislation_on.98989.aspx

Also Susan Hodgson ‘video abstract’ on this paper available here: https://journals.lww.com/epidem/Pages/videogallery.aspx?videoId=33&autoPlay=true

Posters presentations:

Poster (Regression discontinuity design and policy evaluation: an evaluation of smoke free

legislation on birth outcomes. Ioannis Bakolis, Ruth Kelly, Daniela Fecht, Nicky Best, Anna Hansell, Christopher Millett, Kevin Garwood and Susan Hodgson) - 8th UK and Ireland Occupational & Environmental Epidemiology Meeting, London, April 2014

Poster (Smoke-Free Legislation and Adverse Pregnancy Outcomes in England

Ioannis Bakolis, Ruth Kelly, Daniela Fecht, Nicky Best, Anna Hansell, Christopher Millett, Kevin Garwood, Paul Elliot , Susan Hodgson) International Society of Environmental Epidemiology, Seattle, Washington, August 2014

Poster (Regression Discontinuity Design and Policy Evaluation: an Evaluation of Smoke Free Legislation on Adverse Pregnancy Outcomes Ioannis Bakolis, Nicky Best, Daniela Fecht, Anna Hansell, Christopher Millett, Paul Elliot, Kevin Garwood, Ruth Kelly, Susan Hodgson, International Society of Environmental Epidemiology, Seattle, Washington, August 2014

SAHSU has a long record of publishing its research in high quality peer reviewed journals and presenting results at scientific meetings and conferences to inform policy and to empower public debate. SAHSU puts details of its research on its website (http://www.imperial.ac.uk/school-public-health/epidemiology-and-biostatistics/small-area-health-statistics-unit/), including publications and outputs.

Where results are likely to be of particular interest, SAHSU put out a press release and, if necessary, hold a press conference e.g. for the SAHSU Environment and Health Atlas for England and Wales published in 2014, SAHSU held a press conference and several media interviews, including the Assistant Director of SAHSU being interviewed on the BBC Radio 4 Today programme. SAHSU also respond to media enquiries relevant to SAHSU’s work e.g. the Assistant Director of SAHSU took part in a Newsnight report on health effects of air pollution, broadcast 17 October 2016.SAHSU also present its work at scientific advisory committees where of particular national interest e.g. some of SAHSU's work on the incinerators project will be considered at forthcoming meetings of the Committee on Carcinogenicity (COC) and the Committee on Toxicity of chemicals in foods, consumer products and the environment (COT).

SAHSU puts details of its research on the SAHSU website (http://www.imperial.ac.uk/school-public-health/epidemiology-and-biostatistics/small-area-health-statistics-unit/), including publications and outputs. For the SAHSU Environment and Health Atlas for England and Wales, SAHSU developed a public-facing website with interactive searchable maps and explanatory text (www.envhealthatlas.co.uk) working with the NGO Sense About Science.

SAHSU take part in a wide range of public facing events, both general and project specific For example, in June 2016, members of SAHSU presented work at the ‘Life Bank- Interactive Science Event’ as part of MRC Festival of Medical Research which targeted young members of the public aged 18-40 years old, including on the Environment and Health Atlas for England and Wales (involving nine cancer outcomes mapped at small area level across England and Wales), bioaerosols and health effects of environmental noise. See video at https://www.youtube.com/watch?v=ml4XyHs720I - A look at how your environment affects your health at the MRC festival.

SAHSU present work and also approaches to data handling to the MRC-PHE Centre for Environment and Health Community Advisory Board. In addition to meetings with the MRC-PHE Centre Community Advisory Board, SAHSU also meet with various community organisations e.g. the assistant director attends noise committee meetings of Environmental Protection UK and provides research updates and meetings with government departments.

SAHSU also present its work at scientific advisory committees where of particular national interest. Besides details of SAHSU research can be accessed via its website http://www.imperial.ac.uk/school-public-health/epidemiology-and-biostatistics/small-area-health-statistics-unit/), including publications and outputs, SAHSU's Environment and Health Atlas for England and Wales, SAHSU developed a public-facing website with interactive searchable maps and explanatory text (www.envhealthatlas.co.uk) working with the NGO Sense About Science. Policy makers.

In 2015, SAHSU attended the launch of the Respiratory Health of the Nation project, which used respiratory hospital admission, mortality and cancer registrations data, at the House of Commons in July. This project presented SAHSU maps of the respiratory conditions. In January 2018, the Assistant Director presented information on SAHSU noise and health studies to the All Party Parliamentary Group on Heathrow Expansion.

In 2017 and 2018, members of SAHSU also presented work at Imperial Festival, the university’s annual public engagement showcase. In 2017, SAHSU members contributed to exhibits on both the health benefits of greenspace, and more generally on the health effects of environmental pollutants such as air pollution and noise. In 2018 the Centre for Environment and Health organised exhibits on both exposomics, and more specifically on work related to SAHSU in an exhibit entitled “Big data, small areas”, which involved demonstrating the Environment and Health Atlas for England and Wales, outlining how SAHSU uses routine health and environmental data, and also covering noise and air pollution in London. SAHSU members also took part in the MRC Festival of Medical Research in June 2017, in a public event for the community of Deptford demonstrating work on bioaerosols and health effects of environmental noise.

The Centre for Environment and Health and the Health Protection Research Unit in Health Impacts of Environmental Hazards have a joint community advisory board, a stakeholder group that provides input to research to and guidance on research projects – in 2017 SAHSU members have provided presentations on the estimation of costs to the NHS and social care due to the health impacts of air pollution, the use of personal data and noise as a public health problem.

This agreement permits Imperial College London to continue to hold the NN4B data disseminated by ONS, but not to otherwise process it. The remainder of the wording in this Objective for Processing section relates to processing established under the last approved agreement V0.6

The Small Area Health Statistics Unit (SAHSU) is a long-standing and internationally-recognised centre of excellence assessing the risk of exposure to environmental pollutants to the health of the population, with an emphasis on the use and interpretation of routine health statistics at small-area level. SAHSU was established in 1987 as a recommendation of the Black enquiry into the incidence of leukaemia and lymphoma in children and young adults near the Windscale/Sellafield nuclear power plant. SAHSU has a particular role nationally in carrying out environmental health surveillance of the population in relation to environmental contaminants and point sources of industrial pollution, based on routinely collected health data. This is a highly specialised area of work requiring excellence in computing, database management, geographical information systems (GIS), statistics, environmental exposure assessment and epidemiology. The set of skills and expertise that has been established and built up in SAHSU is a unique resource both nationally and worldwide.

SAHSU holds comprehensive computerised sets of health and demographic data and a range of environmental datasets at high spatial resolution.

SAHSU is funded by Public Health England (PHE) to contribute to public health in the UK. SAHSU has a programme of work established which is defined by the following terms of reference: -

• Developing and maintaining databases of health data, environmental exposures as required to meet specific need, also of social confounding factors at a small-area level

• Carrying out substantive research studies on environment and health issues

• Working in collaboration with other scientific groups, to build up reliable background information on the distribution of environmental exposure, socio-economic data and disease amongst small areas

• Acting as a centre of expertise, disseminating information on developments in spatial epidemiological methods to regional, national and international groups

• Responding rapidly, with expert advice, to ad hoc queries from the core funding bodies (Department of Health and Public Health England) about unusual clusters of disease, particularly in the neighbourhood of industrial installations

To deliver against the Terms of Reference, SAHSU utilises the research database to meet the following purposes:

Purpose 1 - Maintenance of the SAHSU health research database

At the core of the overall programme of work is the maintenance of the SAHSU research database, which combines multiple datasets and has both ethics and s251 approvals in place. A particular strength is the maintenance of historic data, which allows SAHSU to examine long term trends and use of data at high spatial resolution (address and postcode), which are crucial for studies of environmental exposures determined by spatial location e.g. electromagnetic field exposure arising from proximity to an overhead power line.

Purpose 2 - To carry out a programme of research projects and studies

The research programme includes both methods development and investigation of priority questions in environment and health. A key aim is to improve the science base underlying translation of knowledge on the effects of the environment on health into policy. SAHSU conducts national research studies on environmental factors that may affect health ranging from exposures to e.g. electromagnetic fields (such as from mobile phone base stations), traffic-related air pollution, road and aircraft noise, water contaminants, waste disposal, using nationally collected patient data including mortality, hospital admissions, cancer registrations and births data. Additional small-area analyses are conducted that help support the general remit of the unit e.g. investigating differential hospital admission rates in ethnically diverse neighbourhoods. SAHSU provides national expertise in cluster detection and small-area statistical methods and has close links with Public Health England including input into PHE's environmental public health tracking programme and surveillance activities.

Purpose 3 - To build up reliable background information on the distribution of environmental exposures, socioeconomic data and disease amongst small areas

SAHSU have developed an extensive collection of environmental exposure data e.g. air pollution, magnetic fields, environmental noise, that SAHSU hold at high spatial resolution, together with geographically-referenced health data as needed in approved studies - all SAHSU studies are controlled via the PHE-SAHSU Liaison Committee. An example of this work is the Environment and Health Atlas for England and Wales, which included 14 conditions (nine cancers) at small area level (website http://www.envhealthatlas.co.uk/homepage/ and OUP book: Hansell AL, Beale LA, Ghosh RE, Fortunato L, Fecht D, Järup L, Elliott P. The Environment and Health Atlas for England and Wales. Oxford University Press, April 2014, Oxford, UK.).

Purpose 4 - To develop methodology for analysing and interpreting health outcomes related to small areas

Some of SAHSU's studies are methodological, relating to for example, statistical uncertainty in observed health risks in areas relating to choice of spatial boundaries or uncertainties in the population estimates; development of methods to detect clusters of disease in time and space (surveillance); development of methods to better adjust for lifestyle factors in health risk analyses by using risk scores constructed at area-level from cohort datasets and surveys in SAHSU's analyses of hospital admissions and mortality.

Purpose 5 - To act as a centre of expertise, disseminating information on developments in spatial epidemiological methods to national and regional groups

SAHSU participate in national and international scientific meetings and provide training to PHE and internationally including to the US Centers for Disease Control (CDC) in use of small area analysis for public health purposes. SAHSU use aggregate non-disclosive data in outputs, presentations and training.

Purpose 6 - To provide rapid ad hoc support to PHE and DH about unusual clusters of disease, particularly in the neighbourhood of industrial installations

Such work is carried out on the instruction of Department of Health or Public Health England, and is approved by the Director of SAHSU. By its nature, such requirements cannot be detailed in advance, but the only outputs would be aggregate with small numbers suppressed, and provided to DH and PHE.

Approval of projects

PHE's representation on the PHE-SAHSU Liaison Committee is to provide oversight of the use of the PHE funding ensuring that it is being used within the remit of the funding agreement. Most SAHSU studies are funded through peer-reviewed grants from research councils such as UKRI, NIHR and the Wellcome Trust and other charities e.g. the Cystic Fibrosis Trust. Even though, PHE provides the core infrastructure funding for SAHSU, they do not have any decision making responsibilities over the project initiations within the SAHSU unit.

Project/study initiations are done by researchers within SAHSU. All new studies using SAHSU data must be approved as a "SAHSU-study". To do so, researchers have to provide a project outline detailing the project rational, its relevance to patients and the public (i.e. health and/or social care) and which data will be required. The study can then be approved by either the Director or Assistant Director of SAHSU under consideration of SAHSU's overall programme terms of reference and whether the study is adequately covered by SAHSU's existing ethical approval and if not, separate ethical approval must be sought.

Once approved internally, the project is introduced to PHE via the PHE-SAHSU Liaison Committee which will provide confirmation that the project falls within the PHE-SAHSU funding remit and will then be forwarded to get formal minuted approval from the appropriate PHE programme board attended by a member of the Department of Health (e.g. Environmental Hazard Board).

SAHSU have a single s251 support in place to cover the above. Any project which may have additional requirements (for example to require the linkage of an additional dataset beyond that previously agreed) must seek an amendment to existing s251 and ethics approvals. It would also be outside the scope of this application, and therefore an amendment would be put before IGARD for consideration.

ONS NN4B (2006-2012)

SAHSU currently hold ONS NN4B data from period 2006 to 2012 which have been used to link to the ONS birth registrations (live and still birth). SAHSU have HRA-CAG approval (Ref - 14/CAG/1039) and London - South East Research Ethics Committee approval (Ref: 17/LO/0846) to hold and link ONS Birth registrations to NN4B data. SAHSU have not been able to get more up to date NN4B data from ONS, as of 2015 NN4B has been replaced with the Personal Demographics Service and now held by NHS Digital.

The gestational age and ethnicity information from NN4B were added to ONS birth registration data to create an enhanced dataset for use in SAHSU research.

The gestational age information is useful for SAHSU research for the following reasons:

1) gestational age is needed to correctly define low birth weight data some babies have low birth weight due to being born early rather than any actual growth retardation;

2) to more accurately define trimester/pregnancy specific exposures by allowing a day of conception (i.e. the first day of potential exposure) to be calculated;

3) to define specific reproductive outcomes such as pre-term delivery. Adjustment for ethnicity is crucial in a range of studies and without individual level data area-level measures of ethnicity must be used.

4) Evaluation of birth weight trends

5) Construction of Birth weight charts sex-specific and ethnic-specific

6) Validation of the existing birth weight charts and evaluation of the misclassification rates

7) Evaluation of stillbirths in relation to birth weight charts

This can be problematic as many reproductive outcomes are strongly linked to ethnicity, for example birth weight varies amongst ethnic groups and without individual ethnicity information definitions and interpretation of low birth weight is less accurate.

The enhanced birth dataset (ONS birth registration + NN4B) has and will enable SAHSU to fulfil its remits to respond rapidly to queries about unusual clusters of disease; to carry out substantive research studies on environment and health issues; to develop and maintain databases of health data, environmental exposures and confounding socio-economic factors as required to fulfil these aims; and to develop methodology for use in small area studies. For example, up-to-date births data with gestational age information would allow for current trends in births weight and birth weight distributions to be investigated.

The NN4B dataset is an invaluable dataset because it combines individual-level information on ethnicity and gestational age, which are both essential to be able to properly interpret birthweight – babies of ethnic minority groups and/or who are born earlier tend to weigh less. This is particularly important to know about and to be able to adjust for in statistical analyses in London, as there are high percentages of ethnic minority groups living in areas experiencing high aircraft noise exposure. This is important for this study, which is likely to influence policy on aircraft traffic.

SAHSU have previously evaluated ONS birth registration, HES and NN4B datasets (Ghosh RE, Ashworth DC, Hansell AL, Garwood K, Elliott P, Toledano MB. Routinely collected English birth data sets: comparisons and recommendations for reproductive epidemiology. Arch Dis Child Fetal Neonatal Ed. 2016 Sep;101(5):F451-7) and concluded that NN4B was the best dataset to use in epidemiological studies. Alternative datasets are not as good and may lead to biased estimates of any associations between noise and birth outcomes – ONS birth registrations do not have information on gestational age or ethnicity; HES data have issues with completeness of both information and coverage.

SAHSU has a particular role nationally in carrying out environmental health surveillance of the population in relation to environmental contaminants and point sources of industrial pollution, based on routinely collected health data. Having national data will enable SAHSU to provide the ad-hoc rapid response to Public Health England. Given that PHE coverage is across England, and the requirements cannot be predicted in advance, national data is required given that response times do not permit time to request, receive and process individual extracts of data. Historical data is also essential for all projects to enable SAHSU to obtain longitudinal data on prior admissions for patients.

The GDPR lawful basis for SAHSU to process this data is Article 6(1)(e) 'task in the public interest' and Article 9(2)(j) 'scientific or historical research purposes or statistical purposes'.

SAHSU's proposed work will continue with the same themes of SAHSU’s programme of work agreed with Public Health England.

Some of SAHSU’s studies for which ONS Birth registration linked to NN4B data are required:

Maternal residential exposure to aircraft and railway noise and risks of adverse birth outcomes: (2019)

The study aims to investigate whether there is an impact of aircraft noise exposure from Heathrow airport on birthweight of babies living near the airport. There is good biological plausibility through noise-induced stress and also the known associations of environmental noise on blood pressure that may affect blood flow to the placenta. The analysis follows on from the SAHSU ‘Traffic in London’ study recently published in the BMJ (Smith RB, Fecht D, Gulliver J, Beevers SD, Dajnak D, Blangiardo M, Ghosh RE, Hansell AL, Kelly FJ, Anderson HR, Toledano MB. Impact of London's road traffic air and noise pollution on birth weight: retrospective population-based cohort study. BMJ. 2017 Dec 5;359:j5299), which examined road traffic noise using the NN4B dataset. The study suggested potential impacts at highest levels of road traffic noise exposure. The impact of aircraft noise on birthweight are important to assess, as aircraft noise exposures are higher in some areas than road traffic noise and that the quality of the noise of an aircraft flying overhead means that noise is more intrusive, also in London aircraft overfly heavily populated areas.

Green Space and Birth Outcomes (on-going)

The availability of green space has been linked to multiple health benefits, with recent studies in the USA and Europe suggesting a link between improved birth outcomes and residential exposure to green space. The aim of this SAHSU study is to explore the associations between green space and birth outcomes in London.

The ONS NN4B dataset for 2006-2012, provides information on approximately 700,000 births per year across England. Outcomes of interest include: 1) birth weight; 2) gestational age at delivery; and 3) small for gestational age 4) preterm delivery, all leading causes of perinatal mortality and morbidity, and associated with increased morbidity in later life. Maternal address at delivery will be linked to relevant measures of green space exposure/access using LiDAR data on ground cover vegetation and trees for Greater London and OS MaterMap.

The impact of potentially confounding variables, including maternal age, parity and air pollution, as well as area-level socio-economic deprivation and smoking will be explored.

Traffic in London: (on-going)

The objectives of this study are to investigate population exposures in London to traffic pollution (including air and noise) and relationships with health, including examining traffic-related air pollution, aircraft noise and road noise in relation to adverse birth outcomes such as low birth weight.

This MRC-PHE centre study lead by Kings College London aims to describe and understand the patterns of exposure of the population in London to traffic pollution (including air and noise) and their relationships to health (http://www.kcl.ac.uk/lsm/research/divisions/aes/research/ERG/research-projects/traffic/index.aspx). The consortium of over 20 investigators has a wide range of work packages. SAHSU related deliverables are to quantify relationships between traffic noise and air pollution and the following health outcomes: mortality, hospital admissions and adverse birth outcomes including low birth weight in the study period 2003-10.

Air pollution data come from the Environmental Research Group at Kings College and noise exposures have been modelled at Imperial. ONS birth registrations are linked with NN4B data to generate an enhanced and added-value ONS birth dataset with gestation age and ethnicity which is important for accurate exposure estimation and outcome interpretation. Postcodes are used in order to accurately estimate exposures at residential address.

Incinerators: (on-going)

This national study investigates whether emissions from solid municipal waste incinerators (MSWis) in operation after implementation of the EU Waste Incineration Directive (WID) (2000176/EC) pose a risk to reproductive and infant health. Modelled ground level concentrations of emissions from 22 MSWis in 2003-2010 will be investigated in relation to birth weight low/very low birth weight, preterm delivery, stillbirths and small for gestation age.

Small for gestational age (SGA): on-going

Small for gestational age (SGA) is normally defined as a baby with a weight below the 10th percentile for their sex and gestational age. Defining the gender-specific birth weight for gestational age can be done in two ways, 1) a within study distribution or; 2) using pre-defined centile charts based on other studies. The main pre-defined reference curves currently in use in the UK are based on the British 1990 (UK90) reference which is based on measurements from white British children born between 1983 and 1994. Additional ethnic specific centile charts have since been produced. A recent study investigated whether the UK90 centile charts predicted neonatal outcomes better than an ethnic-specific one using data from 9102 births in the Born in Bradford cohort. This project will use national data for the whole of England and Wales (2006-2014) to calculate national centile charts, including ethnic-specific centile charts. These will be used to calculate the risk of being SGA as compared to using the UK90 and ethnic specific centile charts.

Other projects that will require NN4B data are:

1. Evaluation of birth weight trends:

2. Evaluation of stillbirths in relation to birth weight charts:

3. Construction of Birth weight charts sex-specific and ethnic-specific:

4. Validation of the existing birth weight charts and evaluation of the misclassification rates:

Smoking ban:

This study examined the impact of the smoke-free legislation on rates of preterm birth, low birth weight (LBW) and small for gestational age (SGA). As a consequence of the Health Act 2006, England successfully implemented comprehensive smoke-free legislation in July 2007, prohibiting smoking in all enclosed or partially enclosed public spaces. Few studies have examined impact of interventions to reduce exposure to second-hand smoke on pregnancy outcomes.

Smoking ban:

This study examined the impact of the smoke-free legislation on rates of preterm birth, low birth weight (LBW) and small for gestational age (SGA). As a consequence of the Health Act 2006, England successfully implemented comprehensive smoke-free legislation in July 2007, prohibiting smoking in all enclosed or partially enclosed public spaces. Few studies have examined impact of interventions to reduce exposure to second-hand smoke on pregnancy outcomes.

Protective effects of smoke-free legislation on birth outcomes in England - a regression discontinuity design. Bakolis, Ioannis; Kelly, Ruth; Fecht, Daniela; Best, Nicky; Millett, Christopher; Garwood, Kevin; Elliott, Paul; Hansell, Anna L; Hodgson, Susan. Published ahead of print - doi: 10.1097/EDE.0000000000000534 available http://journals.lww.com/epidem/Abstract/publishahead/Protective_effects_of_smoke_free_legislation_on.98989.aspx

Also Susan Hodgson ‘video abstract’ on this paper available here: https://journals.lww.com/epidem/Pages/videogallery.aspx?videoId=33&autoPlay=true

Posters presentations:

Poster (Regression discontinuity design and policy evaluation: an evaluation of smoke free

legislation on birth outcomes. Ioannis Bakolis, Ruth Kelly, Daniela Fecht, Nicky Best, Anna Hansell, Christopher Millett, Kevin Garwood and Susan Hodgson) - 8th UK and Ireland Occupational & Environmental Epidemiology Meeting, London, April 2014

Poster (Smoke-Free Legislation and Adverse Pregnancy Outcomes in England

Ioannis Bakolis, Ruth Kelly, Daniela Fecht, Nicky Best, Anna Hansell, Christopher Millett, Kevin Garwood, Paul Elliot , Susan Hodgson) International Society of Environmental Epidemiology, Seattle, Washington, August 2014

Poster (Regression Discontinuity Design and Policy Evaluation: an Evaluation of Smoke Free Legislation on Adverse Pregnancy Outcomes Ioannis Bakolis, Nicky Best, Daniela Fecht, Anna Hansell, Christopher Millett, Paul Elliot, Kevin Garwood, Ruth Kelly, Susan Hodgson, International Society of Environmental Epidemiology, Seattle, Washington, August 2014

SAHSU has a long record of publishing its research in high quality peer reviewed journals and presenting results at scientific meetings and conferences to inform policy and to empower public debate. SAHSU puts details of its research on its website (http://www.imperial.ac.uk/school-public-health/epidemiology-and-biostatistics/small-area-health-statistics-unit/), including publications and outputs.

Where results are likely to be of particular interest, SAHSU put out a press release and, if necessary, hold a press conference e.g. for the SAHSU Environment and Health Atlas for England and Wales published in 2014, SAHSU held a press conference and several media interviews, including the Assistant Director of SAHSU being interviewed on the BBC Radio 4 Today programme. SAHSU also respond to media enquiries relevant to SAHSU’s work e.g. the Assistant Director of SAHSU took part in a Newsnight report on health effects of air pollution, broadcast 17 October 2016.SAHSU also present its work at scientific advisory committees where of particular national interest e.g. some of SAHSU's work on the incinerators project will be considered at forthcoming meetings of the Committee on Carcinogenicity (COC) and the Committee on Toxicity of chemicals in foods, consumer products and the environment (COT).

SAHSU puts details of its research on the SAHSU website (http://www.imperial.ac.uk/school-public-health/epidemiology-and-biostatistics/small-area-health-statistics-unit/), including publications and outputs. For the SAHSU Environment and Health Atlas for England and Wales, SAHSU developed a public-facing website with interactive searchable maps and explanatory text (www.envhealthatlas.co.uk) working with the NGO Sense About Science.

SAHSU take part in a wide range of public facing events, both general and project specific For example, in June 2016, members of SAHSU presented work at the ‘Life Bank- Interactive Science Event’ as part of MRC Festival of Medical Research which targeted young members of the public aged 18-40 years old, including on the Environment and Health Atlas for England and Wales (involving nine cancer outcomes mapped at small area level across England and Wales), bioaerosols and health effects of environmental noise. See video at https://www.youtube.com/watch?v=ml4XyHs720I - A look at how your environment affects your health at the MRC festival.

SAHSU present work and also approaches to data handling to the MRC-PHE Centre for Environment and Health Community Advisory Board. In addition to meetings with the MRC-PHE Centre Community Advisory Board, SAHSU also meet with various community organisations e.g. the assistant director attends noise committee meetings of Environmental Protection UK and provides research updates and meetings with government departments.

SAHSU also present its work at scientific advisory committees where of particular national interest. Besides details of SAHSU research can be accessed via its website http://www.imperial.ac.uk/school-public-health/epidemiology-and-biostatistics/small-area-health-statistics-unit/), including publications and outputs, SAHSU's Environment and Health Atlas for England and Wales, SAHSU developed a public-facing website with interactive searchable maps and explanatory text (www.envhealthatlas.co.uk) working with the NGO Sense About Science. Policy makers.

In 2015, SAHSU attended the launch of the Respiratory Health of the Nation project, which used respiratory hospital admission, mortality and cancer registrations data, at the House of Commons in July. This project presented SAHSU maps of the respiratory conditions. In January 2018, the Assistant Director presented information on SAHSU noise and health studies to the All Party Parliamentary Group on Heathrow Expansion.

In 2017 and 2018, members of SAHSU also presented work at Imperial Festival, the university’s annual public engagement showcase. In 2017, SAHSU members contributed to exhibits on both the health benefits of greenspace, and more generally on the health effects of environmental pollutants such as air pollution and noise. In 2018 the Centre for Environment and Health organised exhibits on both exposomics, and more specifically on work related to SAHSU in an exhibit entitled “Big data, small areas”, which involved demonstrating the Environment and Health Atlas for England and Wales, outlining how SAHSU uses routine health and environmental data, and also covering noise and air pollution in London. SAHSU members also took part in the MRC Festival of Medical Research in June 2017, in a public event for the community of Deptford demonstrating work on bioaerosols and health effects of environmental noise.

The Centre for Environment and Health and the Health Protection Research Unit in Health Impacts of Environmental Hazards have a joint community advisory board, a stakeholder group that provides input to research to and guidance on research projects – in 2017 SAHSU members have provided presentations on the estimation of costs to the NHS and social care due to the health impacts of air pollution, the use of personal data and noise as a public health problem.