SAHSU maintains a large data collection of health records and population-based data that allows us to study trends in chronic disease including environmental risks. To protect the health of the population and improve health care outcomes, we need data on the entire population in order to investigate national environmental health concerns, conduct disease surveillance and detect disease clusters.

Our health data collection consists mainly of the following:

  • Hospital Episode Statistics (HES) - All admissions for Admitted Patient Care, Critical Care and attendances for Emergency Care at NHS hospitals in England,
  • Cancer registrations (England and Wales),
  • Death, live birth and still birth registrations/notifications.

Our major and unique features of SAHSU are our wide range of environmental and health data and our expertise in handling health data at the small area (neighborhood) level. Our national health data are stored, processed, and analysed within the SAHSU Secure Research System (SSRS) facility consisting of two separate secure areas within the Imperial College network with appropriate security controls implemented for data protection. Our data fields include postcode or address of residence which are held in an encrypted format with restricted access. The geographical information is essential for our small area analyses. This allows us to obtain an accurate link to UK administrative and census geography as well as other contextual information including environmental exposures and to accurately investigate diseases, health risks and detect disease clusters.

Our health data come from several data providers including NHS England, the Office for National Statistics (ONS), the Welsh Cancer Intelligence & Surveillance Unit (WCISU) and other national sources. These data holdings are refreshed on an annual basis or as required for specific studies.

Ethical and governance permissions to hold and use health data for environmental health research have been obtained from the following authorities:

  • Health Research Authority - London South East Research Ethics Committee
  • Health Research Authority - Confidentiality Advisory Group (CAG) advises on Regulations 5 of the Health Service (Control of Patient Information) Regulations 2002 to process patient identifiable information without consent
  • The UK Health Security Agency (UKHSA) Caldicott Advisory Panel advises on Regulation 3 of the Health Service (Control of Patient Information) Regulations 2002 to process patient identifiable information without consent

Non-health data

SAHSU additionally holds small area data from the national Census on populations and socio-economic status (SES), including enumeration districts, census output areas, lower layer super output areas and wards (see Table of Social factor data). We also hold environmental data from several sources (see Table of Environmental data) including our research studies, the Environment Agency, Defra, the Civil Aviation Authority, the UK Health Security Agency, the British Geological Survey and water companies etc. (e.g. see our Environment and Health Atlas for England and Wales ). The maintenance of the databases (health, population, SES and selected environmental data) is conducted by the SAHSU database team.

Table of environmental data

Table of social factor data

Use of data within SAHSU

SAHSU recognises the legal and ethical responsibility to handle confidential and sensitive data carefully and securely. We are fully committed to doing that in a way that maximises its use while preventing unauthorised or inappropriate use or disclosure. We respect the nature of the data we work with, where it comes from and what it means for individuals.

SAHSU data users are required to manage data, in compliance with information governance requirements and government legislation. Special care is taken with data of a sensitive or confidential information sush as health data.

We ensure that the following:

  • Appropriate policies, procedures, accountability, management structures, and computing hardware and software are in place to provide a robust governance framework.
  • Development of a culture of confidentiality and care when handling data.
  • Researcher training - To access data, researchers must complete appropriate Data Security and Information Governance (IG) training with regular refreshers/updates or become an Office for National Statistics (ONS) Approved Researcher.

All our research data are stored, processed, and analysed within the SAHSU Secure Research System (SSRS) facility which sits within the SAHSU secure enclaves that is part of the Imperial College Secure Environment. Personal and sensitive data are held within SAHSU’s secure encrypted database which can only be accessed by the database team. Researchers only have access to pseudonymised data.

We have a robust information governance framework for information management and we have deployed a range of privacy-enhancing technologies, physical security measures, and audit procedures to assure our stakeholders that the data assets entrusted to us for our research programme are handled according to rigorous standards.

All researchers using the data are affiliated with SAHSU. Research study concepts are initially approved by either the Director or Deputy Director of SAHSU, the UK Health Security Agency (UKHSA)-SAHSU Liaison Committee, and have formal minuted approval from the appropriate UKHSA programme board.

Researchers are required to sign the SAHSU Acceptable Use Policy and Agreement, which includes written acceptance of the security controls and guidelines on the processing of personal data before being given access to our research data. The level of data access granted is based on the requirements of the study. Research studies are subject to approval by UKHSA-SAHSU Liaison Committee, Health Research Authority (HRA)  -  London South East Research Ethics Committee, HRA Confidentiality Advisory Group (CAG) , and UK Health Security Agency Caldicott Advisory Panel. Access to health data is additionally controlled by a series of agreements between SAHSU and our data providers (e.g. Office for National Statistics, NHS England, Welsh Cancer Intelligence & Surveillance Unit, etc.). Data users may be required to sign to agree to the written terms set by specific data providers.

Our data processing policies and procedures ensure that all studies involving data that may be potentially identifiable (e.g. data from small geographical areas or small numbers of cases for a particular disease) are carried out within the SSRS environment. The data are processed in compliance with law, statute, and best practices. SAHSU adheres to and conforms to the Office for National Statistics (ONS), NHS England and other national guidelines to suppress small numbers in all research outputs to ensure that individuals cannot be identified.

SAHSU does not share data with third parties.