Women's Health Initiative
Seattle Clinical Center

PI: Shirley Beresford PhD
Co-PI: Vicky Taylor MD, MPH

The Women's Health Initiative, or WHI, is a multicenter study funded by the National Heart, Lung, and Blood Institute of the National Institutes of Health. Established by the NIH in 1991, the WHI involves 40 research institutions throughout the United States.

The WHI Seattle Clinical Center, run jointly by Fred Hutchinson and the University of Washington, was one of the first 16 clinical centers to be involved in the study.

The WHI has two components: a clinical trial and an observational study. Both follow women for nine years who were aged 50-79 at the time of study enrollment. The clinical trial is testing the benefits and risks of hormone therapy, dietary modification, and calcium-plus-vitamin-D supplementation in relation to the overall health of post-menopausal women.

Participants are enrolled in one or multiple arms of the clinical trial or observational study. Primary study outcomes are coronary heart disease, breast and colorectal cancer, and hip fractures. The WHI Seattle Clinical Center began study enrollment in 1993 and is now in the follow-up phase. We enrolled more than 3,000 women into the study: 1,767 into the clinical trial and 1,662 into the observational study. Every month, about 120 women come into the clinic for a follow-up appointment and an additional 175 are contacted by phone or mail. These contacts monitor the health and safety of our participants.

One arm of the study, which involves women with a uterus at the time of enrollment who were randomized to take either placebo or estrogen plus progestin, in July 2002 asked participants to stop taking these pills. This arm has stopped the hormone-study pills because estrogen plus progestin has been demonstrated to have risks that exceed benefits. Specifically, heart attacks, strokes, blood clots and breast cancer occurred in more women on estrogen plus progestin. Fewer women on these hormones had colorectal cancer and hip fractures. There were no differences in the number of women who had endometrial cancer or in the number of deaths. In April 2004, the arm that is studying the balance of risks and benefits of estrogen-alone therapy in women with a hysterectomy also asked participants to stop taking the hormone study pills. This arm stopped because NIH concluded there was enough data to answer the main study question, and the balance of benefits and risks of estrogen alone was not likely to change further. Women taking estrogen alone experienced more strokes, but fewer hip fractures, than those on placebo. Both these groups of women continue to be followed in the clinic. Other arms of the study continue as originally planned.

For more information about the Women's Health Initiative, see: www.whi.org

Women's Health Initiative
Seattle Clinical Center
Fred Hutchinson Cancer Research Center
1100 Fairview Avenue North, MD-B141
Seattle, WA 98109
(206) 667-6551 phone
(206) 667-6550 fax