The Women's Health Initiative recruitment methods and results.

One of the most challenging aspects of the Women’s Health Initiative (WHI) was the recruitment of more than 161,000 women for this long-term prevention trial and observational study. The WHI had many enrollment goals that made recruitment efforts formidable (1). These included the recruitment of postmenopausal women, a group seldom targeted for clinical trials; enrolling minority groups in at least the same proportion as they existed in the general population; and enrolling women willing to participate in a long-term (8–12 year) study. The success of the WHI in meeting these goals can be attributed to several factors: the experience gained from prior studies, such as the National Cancer Institute (NCI)-sponsored Women’s Health Trial (2), the subsequent Women’s Health Trial Feasibility Study in Minority Populations (3), and the Postmenopausal Estrogen/Progestin Interventions Trial (4); detailed planning by the WHI investigators; the dedication of recruiters, staff, and investigators at the clinical centers; and, a social and political climate that enhanced women’s interest in health research. Prior to the WHI, few large-scale prevention or clinical trials focused on postmenopausal women. Indeed, until recently, relatively little emphasis was placed on the recruitment of women of any age into such studies (5). However, during the last decade, a number of forces have come together to change this situation. The stance that women