HomeData access, sharing and collaboration

Million Women Study: Data Sharing

We welcome proposals for data access and sharing by bona fide researchers.

The Million Women Study is publicly-funded, and its rich data collections represent over 20 years of work by participants, funders and researchers. As the study continues, we want to make sure that the information we collect is used as well and as widely as possible for medical research.

This means that as well as using the data ourselves, we share anonymised and pseudonymised data (data with identifiable details removed) with other researchers to maximise its potential. In doing so, protecting confidentiality is our highest priority, and we aim always to maintain the reputation of the study, its funders and participants. In the last 3 years we have approved 55 data sharing requests.

Information resources:

All study participants

  1. Information provided by participants on study questionnaires, at recruitment between 1996 and 2001, and on 4 postal re-survey questionnaires since then. Information has been collected on over 1000 different factors, such as education, height, weight, smoking, alcohol, diet, physical activity, childbearing, use of HRT and other medication, falls and fractures, social participation and caring, and general wellbeing. The study questionnaires can be viewed here.
  1. Follow-up information from NHS databases on deaths, cancer registrations, hospital admissions, and cancer screening. Women in the study gave permission for follow-up of their health through their medical records.

Selected study participants

  1. Around 100,000 women have completed one or more online questionnaires providing additional information on diet and physical activity
  2. Blood samples have been collected for about 60,000 women. So far, genetic and biochemical tests have been done for about 20,000 women.
  3. Additional linked data are available from primary care health records for 200,000 women.
  4. Body size and blood pressure measurements are available for about 4000 women.

A summary of data collected so far can be seen here and the Data Dictionary for recruitment questionnaire data here.

Consent and confidentiality:

Information is received in confidence, and we have promised study participants that their information and biological samples will be treated with absolute confidentiality and will be used only for medical research. Details of our study consent forms can be viewed here.

Our Information Governance and Information Security Policies are available on the Cancer Epidemiology Unit website.

Our data sharing model:

The Data Sharing and Access Policy for the Million Women Study conforms to the Medical Research Council’s Policy on Sharing of Research Data from Population and Patient Studies

We follow a controlled data sharing model, providing access to anonymised or pseudonymised study data only, for collaborating and independent approved researchers. Applications will be considered from commercial organisations for use of the data for medical research only, and not for purely commercial purposes. A flow chart of the data access procedures is available here

Requests are considered by the study’s Principal Investigators (Professor Valerie Beral, Professor Jane Green and Professor Gillian Reeves and Dr Sarah Floud) and the Million Women Study Advisory Committee. Decisions on data access are based on the scientific legitimacy of the requester and of their institution, and on assurances on information security and governance; and with regard to the study’s scientific reputation, the needs of funded study team research, the terms of participant consent, and regulatory requirements. Applications for any NHS linked data must be able to demonstrate the benefit of the use of these data for health and social care purposes. All research using Million Women Study data must have ethical approval.

Million Women Study data are held as part of the Nuffield Department of Population Health’s Richard Doll Centenary Archive and its Data Access Oversight Committee provides independent oversight of Million Women Study data access decisions, and acts as an appeals body for disputed decisions.

Data for sharing are made available under a Data Transfer Agreement between the University of Oxford and the requesting institution; those receiving data agree to keep data secure, to use data for the agreed purpose only, to destroy the data once their study has finished, and not to attempt to identify study participants.

Applying for data:

Requests for access to Million Women Study data should be made by email to the Data Access Coordinator for the Richard Doll Centenary Archive (, using the Million Women Study Data Access Preliminary Enquiry Form