Behind The Scenes
Number Of Participants: 161,808 Average Age Of Women At Enrollment: 63 Percentage Of Minority Women: 17.5
Participants in the Women's Health Initiative had to be between the ages of 50 and 79 and past menopause. There were restrictions; women who had breast cancer, for example, were not allowed to join the clinical trials. Women were given physicals; blood samples were taken. Those in the low-fat-diet and hormone-replacement-therapy studies (women could join both) were randomly assigned one of two groups within each trial. Half of the hormone group members took hormone pills; the other half, a placebo. In the low-fat trial, dieters met in groups with a nutritionist weekly (tapering off to quarterly) to learn how to reduce dietary fat. The others ate normally.
At six months and one year, participants underwent physicals. Then they were asked to volunteer for the calcium and vitamin D trial; half popped vitamin pills twice a day, while the others took placebos. For the next six to 11 years, trial members got an annual checkup. Women in the observation-only part of the WHI underwent physicals during the first and third years. And they completed a yearly 10-page survey regarding their health, diet, and lifestyle.
This story appears in the March 6, 2006 print edition of U.S. News & World Report.