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Release: July 9, 2002

UI Among Centers Ceasing Estrogen Plus Progestin Trial

The National Heart, Lung and Blood Institute (NHLBI) announced this morning at a news conference held in Washington, D.C., that it has stopped early the estrogen plus progestin portion of the Women's Health Initiative (WHI) after overall health risks were found to exceed the health benefits. The clinical trial was designed to assess the major health benefits and risks of estrogen plus progestin, the most commonly used hormone preparation in the United States on healthy postmenopausal women with intact uteruses.

The University of Iowa is one of 40 clinical centers in the United States that enrolled women in this arm of the WHI. Due to the importance of the findings, the study is being released early by the Journal of the American Medical Association (JAMA) at its Web site and will appear in the July 17 issue of the journal. The NHLBI news release is available online at

All women who have participated in this WHI component are being informed that the study has stopped and are being asked to return their remaining study pills. Additional information for participants is posted at A total of 16,608 postmenopausal women ages 50 to 79 were enrolled in the study between 1993 and 1998. A total of 1,100 women originally were enrolled at three sites overseen by the UI: Iowa City (398 women originally enrolled), Des Moines (405 originally enrolled) and Davenport (297 originally enrolled). Approximately half the participants were randomly assigned to a daily dose of estrogen plus progestin and half were randomly assigned to a placebo. Even though the trial has stopped, the UI wants to continue to monitor these participants.

A separate WHI study in which the UI participates involves women who have had a hysterectomy taking only estrogen. This estrogen-only study will continue, and women who are participants in this study will be asked continue to take their study medications. Some women originally enrolled in the estrogen-progestin study who had a hysterectomy were moved to the estrogen-only trial. These women, however, will be asked to stop taking their pills.

Women who are participating through the UI in the estrogen-progestin portion of the WHI or other WHI studies who have questions may call one of these toll-free or local numbers: Iowa City area (800) 814-9535 Davenport area (800) 344-3515 or (563) 324-3545 Des Moines (800) 347-8164 or (515) 241-8989.

All WHI studies in which the UI participates are based in the Preventive Intervention Center in the UI College of Public Health. (Information on the other WHI studies is provided below.)

The following UI investigators were involved in the estrogen-progestin arm of the WHI. Their roles in the study are indicated first; their UI titles are listed second.

Robert Wallace, principal investigator for the UI's participation in the trial M.D., Ph.D., the Irene Ensminger Stecher Cancer Professor and UI professor of epidemiology and internal medicine.

Susan Johnson, chief gynecologist for the study M.D., UI professor of obstetrics and gynecology, and associate dean for faculty affairs in the UI Roy J. and Lucille A. Carver College of Medicine.

James Torner, co-principal investigator Ph.D., UI professor of epidemiology.

Linda Snetselaar, dietary expert Ph.D., UI associate professor of epidemiology.

Bradley Van Voorhis, gynecologist M.D., UI professor of obstetrics and gynecology.

Information about other WHI studies, which will continue and in which the UI participates.

* The estrogen plus progestin study is one of two studies that make up the Hormone Replacement Therapy (HRT) clinical trial portion of the WHI. The other HRT study is the investigation of estrogen alone in women who had a hysterectomy before joining the WHI program. This study continues unchanged because, as the NHLBI reports, at this point, the balance of risks and benefits of estrogen alone still is uncertain. The estrogen-only study involves a total of 10,739 women nationwide. The UI originally enrolled 562 women in this trial.

The UI participates in two other clinical studies that are part of the WHI. Among women who are part of the estrogen-progestin trial being stopped, many have been participating in, and are eligible to continue participating in, one of these two clinical studies: the dietary modification arm or the calcium plus vitamin D arm, both of which are described below.

* Dietary Modification Study - This WHI trial studies the effects of low-fat eating patterns on breast and colorectal cancer, heart disease and other disease outcomes. More than 48,000 women ages 50 to 79 are participating nationwide in this component. The UI originally enrolled 1,003 women in this dietary modification study.

* Calcium plus Vitamin D Supplementation Study - Women enrolled in this trial are either taking these supplements or a placebo. This trial is designed to study the effects of calcium plus vitamin D on hip and other fractures, colorectal cancer and other disease outcomes. Women in this trial are either enrolled in the dietary trial or one of the hormone arms (no one is enrolled only in the calcium plus vitamin D trial). Approximately 45,000 postmenopausal women ages 50 to 79 are enrolled nationwide in the study. The UI originally enrolled 1,535 women in this supplementation study.

Altogether, the two HRT studies, the dietary modification study and the calcium plus vitamin D study originally enrolled through the UI approximately 2,400 women, with some women participating in two or more studies.

The UI also participates in an observational trial that is part of the WHI:

*This observational trial tracks the health of more than 93,000 women between ages of 50 and 79. The study goals include learning more about health risk factors, including reliable estimates of the extent to which known risk factors predict heart disease, cancers and fractures. The UI originally enrolled 3,118 women in the WHI observational study.

The WHI also includes a Community Prevention Study, a five-year cooperative venture with the Centers for Disease Control and Prevention that is a study of strategies to enhance adoption of healthful behaviors through a multi-disciplinary approach. However, the UI does not participate in this study.

A backgrounder on the WHI is available online at