Privacy Notice

This privacy notice describes what the Kids’ Environment and Health Cohort is, what data are held in the cohort, and how the cohort is set up.  It also describes how to get further information about this project, and what to do if you do not want your data to be included as part of the Kids’ Environment and Health Cohort.

We are a team of researchers from University College London (UCL). UCL is the data controller for the database created in this project.  We (UCL) are also working with the London School of Hygiene and Tropical Medicine, London School of Economics and Political Science, City, University of London, and Brock University (via one of the project co-investigators, Dr Samantha Hajna). Note that no data will leave the UK at any point, and researchers can only access the data from locations in the UK. 

Children are much more vulnerable to harmful substances in and around their homes and schools than adults. Many children in England also lack access to services and infrastructure where they live and go to school. Living in areas with high outdoor air pollution or near to fast food shops and having no access to green space during childhood is associated with the development of long-term conditions such as asthma, mental health problems and obesity. In this project, we are setting up a new research database, the Kids’ Environment and Health Cohort, to allow research into how the local environment influences health and education in children, and to help understand whether environmental policies introduced by national or local government are improving children’s lives in England.

The Kids’ Environment and Health Cohort: a national birth cohort containing de-identified data from all children born in England from 2006 onwards – around 11 million children by 2023. We expect the cohort to be updated annually.

The Cohort will hold routinely collected, linked data from vital statistics (births and deaths) registration and census, health, and education records from children from birth until adolescence. Children’s records will be linked to their mothers’ health record up to a year before birth to allow researchers to take into account environmental exposures and maternal health during pregnancy. It will be possible to link environmental data to the children’s home and school locations via NHS address records and school records. This will be done in a secure way (see below) which protects children’s identities and home and school addresses.

The Kids’ Environment and Health Cohort will be held in the will be held by the Office for National Statistics (ONS) in a Trusted Research Environment. You can read about Trusted Research Environments here:  

The Kids’ Environment and Health Cohort will hold linked
data from the following datasets:

  • ONS birth and death registration data
  • Census 2011 and 2021 data (for children born within two years of each Census)
  • Hospital Episode Statistics, which contains data on hospital contacts
  • Maternity Services Data, which holds data on maternal health during pregnancy
  • Mental Health Dataset, which holds information on referrals to mental health services
  • Community Dispensing Data, which holds information on dispensed medicines, including for asthma
  • National Pupil Database, which holds data on all children in state school, including special educational needs provision and exam results. It also includes information on children attending early years settings if they receive any free hours entitlement.
  • Personal Demographic Service (NHS address records) and school address data provided by the Department for Education. These will be to link data on the local environment to children’s data. Addresses will be encrypted for this linkage to take place; researchers will never see the full addresses.


A number of environmental datasets about small areas across England, including on air pollution, energy efficiency of buildings, and proximity to major roads, will be linked to the de-identified health and education data as part of setting up the Cohort.

Once the Kids’ Environment and Health Cohort is set up, researchers may apply to UCL (the data controller) to link in further small-area level environmental dataset via children’s home addresses or school addresses). Researchers will need to meet a number of strict criteria in order to do this, to ensure confidentiality at all times.

All data are kept on highly secure servers at the Office for National Statistics.

Researchers will not be able to access identifying variables such as names, NHS numbers or dates of birth.

The data on children’s home or school addresses will be kept separately to the health and education data. Researchers will not be able to access the address records – these can only be accessed by a small number of staff at ONS. If researchers would like to link further environmental data into the cohort, addresses will be encrypted by ONS staff for this linkage to take place; researchers will never see the full addresses.

Access to the cohort will only be granted to researchers who a) have received ethical approval for their project, b) have demonstrated that their project will support children’s health and education via improvements in living environments, c) protect children’s and mothers’ confidentiality at all times, and d) have received training in how to analyse sensitive datasets safely.

The various vital statistics, health, census and education data will be linked together using identifying information about mothers and children. This will be done by staff at ONS and NHS England. ONS will link birth registration data for the children to death data and their mothers’ 2011 and 2021 Census records.

ONS will securely transfer mother and child identifying information (including NHS numbers and dates of birth) to NHS England, who will link the mothers and children to their address histories, health data, and children’s pupil reference numbers in education data. The address histories and pupil reference numbers, and the linked health data will be transferred back to ONS. ONS will transfer the pupil reference numbers to the Department for Education who will extract the education records for the children in the cohort and transfer these back to ONS.

The health data, Census data, education and vital registration data will be de-identified (that is, all identifying information, such as names, dates of birth and NHS numbers, will be removed), before the datasets are placed in the ONS Trusted Research Environment (called the Secure Research Service). Researchers will access the Kids’ Environment and Health Cohort data for their projects via the ONS Secure Research Service.

A smaller number of environmental datasets, including on air pollution and distance to roads, will also be linked to the cohort by ONS staff via the ONS address records as part of setting up the cohort. Researchers will not access these address records.

All researchers working with the data need special training in keeping data confidential and secure. The ONS and NHS England also adheres to strict levels of training and confidentiality awareness for its staff. 

Results from studies using Kids’ Environment and Health Cohort data will be published in open access journals so that they can be read online and downloaded for free. We will announce these publications and provide lay summaries for each research project using data of our results on our website:

There are a number of legal bases for processing the data in the Kids’ Environment and Health Cohort.

Under the General Data Protection Regulations (GDPR), the legal basis for processing personal data for Kids’ Environment and Health Cohort fall under Article 6(1)(e), “a task carried out in the public interest”, and Article 9(2)(j), “processing is necessary for archiving purposes in the public interest, scientific or historical research purposes or statistical purposes”.

Personally identifying information (including names, addresses, dates of birth and NHS numbers) will be processed by NHS England and the Office for National Statistics in order to link the data. For any data linked by NHS England, this is conducted under section 251 of the National Health Services Act (2006) and its Regulations, the Health Service (Control of Patient Information) Regulations (2002). The application was reviewed by the Confidentiality Advisory Group (CAG). CAG is an independent group of lay people and professionals which provides expert advice on the use of confidential patient information without consent. CAG recommended that our application should be supported and the Secretary of State for Health and Social Care approved this.

The legal basis for linkage between vital statistics data and education data, and resharing of data for the Kids’ Environment and Health Cohort will be the Digital Economy Act 2017.

We currently have funding to set up the Kids’ Environment and Health Cohort; this lasts until December 2025. The retention period for each constituent dataset in the Kids’ Environment and Health Cohort will differ according to the organisation providing data, but we anticipate that the data approvals will be renewed on a continuing basis.

Each project using data from the Kids’ Environment and Health data will have to specify the amount of time they require to finish their study. Once the project is finished, the project specific data will be archived for 2 years. 

If you would like to know more about the project and how we are using your data, please have a look around our website, or contact us at: You may also contact the principal investigator, Dr Pia Hardelid, post or email, via the UCL Great Ormond Street Institute of Child Health: 

Dr Pia Hardelid

UCL GOS Institute of Child Health 

30 Guilford Street

London WC1N 1EN

Data Protection Officer

University College London

Legal Services, 6th Floor

1-19 Torrington Place






You also have the right to complain directly to the Information Commissioner’s Office, which is an independent regulatory authority set up to uphold information rights.

This research is led by Dr Pia Hardelid at University College London (UCL). It is supported by funding from the Economic and Social Research Council via Administrative Data Research-UK, with additional funding from Health Data Research UK.

University College London is acting as Data Controller for the Kids’ Environment and Health Cohort. You can find further information about how UCL handles data here:

If you have questions or concerns about the study please contact Dr Pia Hardelid:, or 

Dr Pia Hardelid

UCL GOS Institute of Child Health 

30 Guilford Street

London WC1N 1EN