Women's Health Initiative: Clinical Trials (WHI-CT)

Objectives

To assess the safety and efficacy of three interventions on cardiovascular disease (CVD), cancer, and osteoporosis in postmenopausal women.

Background

The clinical trial component of the WHI included three, overlapping randomized comparisons: hormone therapy, dietary modification, and calcium/vitamin D supplementation. The hormone therapy trial randomized womento one of two double-blinded trials: estrogen plus progestin or estrogen alone. The dietary modification trial evaluated the effect of a low-fat, high fruit, vegetable, and grain diet on preventing CVD and cancer. The calcium/vitamin D randomized women to either supplements or placebo. Women could have been randomized into one, two or all three trials.

Ancillary Memory Study: The Women's Health Initiative Memory Study (WHIMS) is an ancillary study to the Women's Health Initiative (WHI). WHIMS was designed to determine the effects of Hormone Therapy (HT) on the development and progression of dementia symptoms in postmenopausal women. Thirty-nine of the 40 WHI Clinical Centers participate in the WHIMS trial. Recruitment of study participants began in June, 1996 and ended in December, 1998. A total of 7,480 women ages 65-79 were recruited from the HT Trial of WHI. Of the 7,480 women, 2,948 are in the estrogen only (E-alone) study for women without a uterus at the time they enrolled and 4,532 are in the estrogen plus progestin (E+P) study for women with a uterus at time of enrollment.

Subjects

A total of 68,132 women, aged 50-79 years were randomized into the three trials. The hormone therapy trial enrolled 16,608 women, 48,835 were randomized into the diet modification trial, and 36,282 were randomized into the calcium/vitamin D trial. Recruitment was carried out in 40 US clinical centers in 1993-1998.

Conclusions

Overall health risks exceeded benefits from use of combined estrogen plus progestin after an average 5.2 year follow-up among healthy postmenopausal US women (JAMA 2002;288:321-333). Over approximately 8 years of follow-up, a low-fat dietary pattern did not reduce the risk of colorectal cancer (JAMA 2006;295:643-654). Calcium with vitamin D supplementation resulted in a small but significant improvement in hip bone density; however, no significant difference was observed in hip fractures (N Engl J Med 2006;354:669-683).

References

Shumaker SA, Legault C, Kuller L, Rapp SR, Thal L, Lane DS, Fillit H, Stefanick ML, Hendrix SL, Lewis CE, Masaki K, Coker LH; Women's Health Initiative Memory Study. Conjugated equine estrogens and incidence of probable dementia and mild cognitive impairment in postmenopausal women: Women's Health Initiative Memory Study. JAMA. 2004 Jun 23;291(24):2947-58.

Shumaker SA, Legault C, Thal L, Wallace RB, Ockene JK, Hendrix SL, Jones BN 3rd, Assaf AR, Jackson RD, Kotchen JM, Wassertheil-Smoller S, Wactawski-Wende J; WHIMS Investigators. Estrogen plus progestin and the incidence of dementia and mild cognitive impairment in postmenopausal women: the Women's Health Initiative Memory Study: a randomized controlled trial. JAMA. 2003 May 28;289(20):2651-62.

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