The Women’s Health Initiative Clinical Trials of Hormones, Diet and Calcium/Vitamin D for the Major Diseases of Aging in Women


Date Thursday June 22nd 2006
Time 4:00-5:00pm
Venue George E. Pake Auditorium

PARC Forum

The Women’s Health Initiative (WHI) included three clinical trials of postmenopausal women, aged 50-79 from 40 U.S. clinical centers, each of which have received considerable media attention in the recent years. The WHI Hormone Trials randomized over 27,000, to active hormone therapy or placebo, with the primary outcome of coronary heart disease (CHD), the leading cause of death in women. The Estrogen plus Progestin (E+P) trial of 16,608 women with a uterus was stopped 3 years prematurely because the risks exceeded the benefits over 5.6 years of follow-up. The Estrogen Only (E-alone) trial of 10,739 women post-hysterectomy was also stopped early, however, there was an overall balance of risks and benefits over 7.1 years. The WHI Diet Trial randomized 48,835 women to either a group-based diet intervention designed to reduce total fat intake to 20% of daily calories and increase vegetable & fruit servings to 5/day and grains to 6/day or to a control group for an average 8.1 years. Weight loss was not a goal of the intervention, but was measured throughout the trial. The primary outcomes were breast and colorectal cancer, the 2nd and 3rd causes of cancer death in women and although there were no significant differences between groups for these outcomes, breast cancer was significantly reduced in the women with the highest fat intake at baseline who were assigned to the diet, compared to control. The Calcium/Vitamin D trial randomized 36,282 women to daily calcium and vitamin D supplements or placebo for an average 7 years to determine the effects of supplementation on hip and other bone fractures. These supplements reduced hip fractures significantly in women aged 60 and over at baseline, but did not benefit younger women. The results for all 3 trials and “the story behind the headlines” will be presented by Marcia Stefanick, Chair of the WHI Steering Committee and Principal Investigator of the Stanford WHI clinical center.


Marcia Stefanick is a Professor of Medicine at the Stanford Prevention Research Center, Stanford University School of Medicine, where she also has a courtesy appointment as Professor of Obstetrics and Gynecology, by courtesy. She obtained a B.A. in biology from the University of Pennsylvania, Philadelphia, PA in 1974, became interested in sex hormone research at the Oregon Regional Primate Research Center, and obtained her PhD in Physiology at Stanford University, CA, USA in 1982.

Dr Stefanick served as Chair of the Women's Health Initiative (WHI) Steering and Executive Committees from 1998 to 2005, at which time she became Chair of the WHI Extension Study Executive Committee, which is overseeing the 5-year continuation of the project nationwide. She is also the Principal Investigator of the (1) Stanford WHI Center which is following 3000 women aged 60-90 years of age, 12% of whom represent minority women, (2) Stanford's site for National Cancer Institute's WHEL trial, which is studying over 3000 breast cancer survivors to determine whether a plant-based diet can prevent breast cancer recurrence; and (3) the Study of Osteoporotic Fractures in Men (the MrOS study) which has studied the health status of 6000 men, aged 65 and over, for over 5 years.

Dr. Stefanick has published extensively in the area of chronic disease prevention and health promotion across the lifespan, for men and women, with a special interest in menopause and sex hormones and she lectures on these topics to both undergraduates and medical school students at Stanford University. She has also been invited to speak on these topics at prominent national and international meetings.

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