Women’s Health Initiative

The Women’s Health Initiative (WHI) launched in 1991 with a $625 million grant from the National Heart, Lung, and Blood Institute, one of the National Institutes of Health. As one of the largest U.S. prevention studies of its kind, the WHI is an ethnically and geographically diverse study of women. It was designed to address risk factors for cardiovascular disease, cancer and osteoporosis — the most frequent causes of death, disability and poor quality of life in postmenopausal women.

At its inception, the WHI consisted of an observational study and clinical trials, with over 161,000 women enrolled at 40 prestigious research centers nationwide. The initial trials tested the effects of postmenopausal hormone therapy, a low-fat diet, and calcium and vitamin D supplements on risk of heart disease, fractures, breast cancer and colorectal cancer.

Since then, WHI investigators, their colleagues and other independent investigators have leveraged program resources to initiate nearly 300 separately funded research projects. The massive WHI database and biospecimen repository is available to all researchers. Scientists have published more than 1800 papers using WHI data.

Fred Hutch serves as the program’s coordinating hub, led by Dr. Garnet Anderson, along with Drs. Ross Prentice and Charles Kooperberg.


return for every dollar invested

The original hormone therapy trial cost $260 million, with a net economic return of $37.1 billion.


quality-adjusted life years

Clinical effects translated into additional QALYs, a measure of “how long you live and how well you live.”


fewer annual cases of breast cancer

The estimated reduction in breast cancer cases each year due to the findings of WHI studies.


women who participated

There are more than 90 women today over the age of 100 still active in the study.

WHI Research Changes Therapies, Saves Lives

In 2002, 5 million postmenopausal women in the U.S. were using combination hormone replacement therapy (HRT) to alleviate the symptoms of menopause and prevent fractures and heart attacks. However, research conducted by the WHI found a direct link between combination HRT and increase in heart disease, stroke and breast cancer.

The WHI findings singularly changed the face of women's medicine around the world. Researchers estimate that the subsequent decrease in the use of combination HRT resulted in a significant reduction in breast cancer cases in several countries and reduced rates of heart attack and stroke in the U.S.

WHI Funding Leads to National Benefits

The NHLBI awarded Fred Hutch additional funding in 2005, 2010 and 2015 to continue study coordination. In these extension phases, the WHI refined main clinical trial findings, identified factors associated with healthy aging and continue to search for more ways to improve women’s health.

The funding supports the WHI by:

  • Providing a research platform well-positioned to address the health concerns of our aging population
  • Preserving and furthering decades of progress in studying and improving women’s health
  • Creating opportunities to demonstrate how improved care reduces long-term health care costs

Read the letter U.S. Senators sent to the NHLBI and NIH, supporting their continued funding of the WHI.

Key Findings for WHI Studies at the Hutch

WHI studies cover a variety of factors that contribute women’s overall health. Our research looks at multiple forms of cancer, bone health, heart health, and other influences on the quality of life for women in middle age and beyond.

Dr. Garnet Anderson

Dr. Garnet Anderson

Dr. Garnet Anderson led a study that linked estrogen-only therapy after a hysterectomy with a reduced risk of developing breast cancer.

Read the article

Dr. Ross Prentice

Dr. Ross Prentice

Dr. Ross Prentice and his team determined a low-fat diet may reduce the risk of ovarian cancer, as well as breast cancer.

Read the article

Dr. Charles Kooperberg

Dr. Charles Kooperberg

Dr. Charles Kooperberg and his colleagues analyzed the genetic data of WHI participants and identified two new areas of the genome associated with body height in African American women.

Read the article

Dr. Marian Neuhouser

Dr. Marian Neuhouser

Dr. Marian Neuhouser and her team determined that multivitamins have no effect on the risk of cancer or heart disease in postmenopausal women.

Read the article

Additional Breakthroughs in Women’s Health

All WHI news
New study of Asian, Native Hawaiian and Pacific Islander populations gets $38.7M grant Fred Hutch will act as coordinating center for large study of cardiovascular and other chronic diseases in overlooked populations September 14, 2023
Fred Hutch’s Dr. Ross Prentice retires Longtime scientist and statistician contributed to Women’s Health Initiative, cancer prevention research and much more January 20, 2023
Do multivitamins and supplements like cocoa flavanols keep cancer, heart disease away? Scientists drill down into crucial Women’s Health Initiative data to get definitive answers on whether supplement use improves our health April 6, 2022
Women’s Health Initiative continues on at Fred Hutch Nearly 30 years after its launch, the WHI and its data are still going strong, producing key findings February 24, 2021

Contact Us For More Information About WHI