Abstract
The surprising results of the Women's Health Initiative (WHI) reported in 2002 had a profound effect on women as well as health care practitioners. The WHI was the largest, randomized clinical trial designed to determine if postmenopausal hormone use prevented cardiovascular disease as well as other age-related disorders in women. While observational studies suggested that postmenopausal use of estrogen could decrease cardiovascular risk by 40% to 50%, the WHI demonstrated that use of continuous-combined estrogen plus progestin was not cardioprotective and was even associated with increased health risks. The estrogen alone trial of the WHI is still in progress, leaving practitioners and some women still in a dilemma. This article addresses the WHI in the context of other studies and discusses possible reasons for the unexpected results.
Hormone replacement therapy (HRT), defined as estrogen and some form of progestogen, and estrogen replacement therapy (ERT), defined as estrogen alone, 1,* are therapies approved by the FDA for the treatment of menopausal symptoms. Menopause is associated with a loss of endogenous estrogen. Diseases such as osteoporosis and cardiovascular disease (CVD) increase in prevalence in postmenopausal women. 2 Therefore, it was reasonable to hypothesize that declining estrogen might play a role in the development of these diseases among aging women. Furthermore, since CVD is the leading cause of death among women, 3 the use of HRT/ERT for primary and secondary prevention of CVD seemed logical. However, in 1998, researchers began to question evidence that supported these assumptions. Shortly thereafter, the American Heart Association recommended that HRT should not be initiated for the secondary prevention of CVD. 4 Most recently, the findings from the Women's Health Initiative (WHI) provided evidence that HRT should not be used for the primary prevention of CVD. 5 This article will describe the findings from the WHI in the context of other studies, and what the future holds for estrogen therapy and disease prevention.