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Epidemiology and Genomics Research Program

Million Women Study

Lead Contact and/or Principal Investigator (PI):

Funded Since: 1996
Funding Source: Cancer Research UK, Medical Research Council
Year(s) of Enrollment: 1996-2001
Study Website: Web Site Policy

The Million Women Study is the largest study of women's health in the world. In 1996-2001, a quarter of U.K. females, then aged 50-64 years (1.3 million women), joined the study. Study participants have provided details about their lifestyle and health and given signed consent for follow-up. Since recruitment, their health has been followed mainly through electronic linkage to routinely collected National Health Service (NHS) records and they have been re-contacted 3 times (1999-03, 2006-7 & 2009-12).

The aim of the study is to provide reliable information on potentially modifiable causes of common and serious illnesses, to help improve individual and public health. The study has described links between smoking, alcohol, obesity, and use of hormone replacement therapy and women's risk of developing various diseases, recently reporting that the harms of smoking and the benefits of stopping were greater in women than previously thought.

The current focus is for research on dementia, osteoporosis, stroke, and other severe disabling conditions that become increasingly common as women age. With this large study, detailed lifestyle information provided by women, and some 15 years follow-up through linkage to NHS medical records, the study is uniquely placed to answer some major outstanding questions about what causes some of the serious conditions associated with aging, and how they might be prevented.