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The Million Women Study aims to investigate the short-term and long-term effects of menopausal hormones, oral contraceptives, reproductive factors, smoking, alcohol, adiposity, physical activity, social interactions and many other factors on the risk of women developing and dying from different types of cancer, heart disease, stroke, dementia and other mental and neurodegenerative disorders in middle and in old age.

The NHS provides extraordinarily efficient ways of establishing and maintaining long-term follow-up for large prospective studies, such as the Million Women Study. Over 99% of the UK population is registered with the NHS and every individual has a unique NHS number. Electronic linkage, using each individual’s NHS number, to routinely collected NHS databases provides virtually complete follow-up information about deaths, emigrations, cancer registrations and hospital admissions.


Study participants are sent postal resurvey questionnaires every 3-5 years. See recruitment and resurvey questionnaires. Additional postal and on-line surveys have been sent to selected samples of the study participants.

Read our findings and publications.