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The Women's Health Initiative Finds Risks with HRT

The Women's Health Initiative was launched in 1991 to study combination HRT (estrogen plus progestin) and estrogen-only HRT. All together, its studies have involved 161,808 healthy post-menopausal women. The following summarizes the study's findings as of 2003.

Compared with women taking a placebo (an inactive pill), women who took estrogen plus progestin experienced:

• Increased risk of heart attack
• Increased risk of stroke
• Increased risk of blood clots
• Increased risk of breast cancer
• Reduced risk of colorectal cancer
• Fewer fractures
• No protection against mild cognitive impairment and increased risk of dementia (study included only women 65 and older)

The study results also show that for every 10,000 women per year taking estrogen with progestin, there would be:

• 6 fewer cases of colon cancer
• 5 fewer cases of hip fracture

Compared with women taking a placebo (an inactive pill), women taking estrogen alone experienced:

• No difference in risk for heart attack
• Increased risk of stroke
• Increased risk of blood clots
• Uncertain effect for breast cancer
• No difference in risk for colorectal cancer
• Reduced risk of fracture

Source: Women's Health Initiative, 2005 (1)

Based on the results of the Women's Health Initiative, the U.S. Food and Drug Administration (FDA) issued a statement in February 2004 encouraging all manufacturers of estrogen and estrogen with progestin drug products indicated for use by postmenopausal women to update the labeling for their products to provide information about possible health risks (5). Furthermore, in May 2005, the U.S. Preventive Services Task Force, supported by the U.S. Agency for Healthcare Research and Quality, issued a new recommendation against the routine use of estrogen to prevent chronic conditions such as heart disease, stroke and osteoporosis in postmenopausal women who have undergone a hysterectomy (6). The Task Force did not examine the effects of estrogen only or combined estrogen and progestin for the treatment of menopausal symptoms, only for the prevention of chronic disease.

Despite these warnings, the National Institutes of Health has stated that the Women's Health Initiative results may not be relevant for women with severe menopausal symptoms. According to the National Institute of Health, "Participants in the Women's Health study were randomly assigned to receive either hormones or placebo, and those women who had menopausal symptoms reported relief from symptoms with hormone use. Women who felt that they needed menopausal hormones to treat severe symptoms may not have been willing to take the chance of not receiving hormones and may, therefore, have been underrepresented in the study." (4)

Imaginis.com Articles on HRT

• Number of Breast Cancer Cases Continue to Decline (May 16, 2007)



• Breast Cancer Deaths Declining (dateline January 20, 2007)



• Estrogen Replacement Therapy May Not Increase Women's Risk of Breast Cancer (dateline June 13, 2006)



• Another Hormone Replacement Therapy Study Stopped Due to Breast Cancer Recurrence Concerns (dateline February 11, 2004)



• Million Women Study Finds Increased Breast Cancer Risk Among Women Who Use Hormone Replacement Therapy (HRT) (dateline October 31, 2003)



• U.S. Government Halts Study on Hormone Replacement Therapy Due to Breast Cancer Risk (dateline August 4, 2002)



• Change in Recommendation Regarding Hormone Replacement Therapy for the Heart (dateline July 27, 2001)



• More Debate About Benefits of Hormone Replacement Therapy (dateline June 21, 2001)



• Large Study Finds Prolonged Use Estrogen Replacement Therapy Increases Risk of Death from Ovarian Cancer (dateline March 22, 2001)



• Hormone Replacement Therapy May Reduce Death Rate and Protect Against Heart Disease in Some Women (dateline January 11, 2001)



• Hormone Replacement Therapy Does Not Further Increase Breast Cancer Risk in Women with Benign Breast Disease, Study Finds (dateline November 27, 2000)



• Contradictory Reports On Hormone Replacement Therapy and Breast Cancer Risk Alarm Women (dateline June 13, 2000)



• Phytoestrogens (Soy) Show Similar Benefits of Hormone Replacement Therapy And Help May Prevent Breast Cancer (dateline May 3, 2000)



• Breast Cancer Diagnosed Earlier, Easier to Treat in Women on Hormone Replacement Therapy (dateline April 11, 2000)



• New Study Links Hormone Replacement Therapy To Breast Cancer Risk (dateline January 31, 2000)

Conclusion

The following chart summarizes the possible benefits and risks of ERT (estrogen without progestin). The benefits and risks may differ when estrogen is combined with progestin. For example, the increased risk of endometrial cancer is not associated with combination hormone therapy.

HRT is a tradeoff between the proven benefits of relieving menopausal symptoms and preventing diseases such as osteoporosis versus the possibility of increasing the risk of breast cancer. If a woman is at high risk of osteoporosis (due to age, family history, small build, etc.) and has a relatively low risk of breast cancer, then HRT may be an easy choice. If a woman is already at high risk of breast cancer due to genetic factors, family history, etc. then the decision to take HRT may be more complicated.

To further add to the confusion, the combined estrogen/progestin arm of the Women's Health Initiative (WHI)-a large clinical trial that was studying HRT, heart disease, osteoporosis, breast cancer, and colon cancer in 63,000 American women between the ages of 50 and 79-was halted in by the National Institutes of Health (NIH) in 2002. Researchers felt that the elevated risk of breast cancer, as well as higher than normal rates of heart attack, stroke, and blood clots, outweighed the benefits that HRT may provide against hip fractures and colon cancer. The arm of the WHI that studied estrogen alone (with progestin) did not find an increase in heath-related problems among women who took estrogen. That arm of the study will continue. At the moment, the best advice experts can give is for women to discuss the benefits and risks of HRT with their physicians and make informed choices.

Additional Resources and References

• (1)For information on the U.S. National Institutes of Health sponsored Women's Health Iniatitive study, please visit http://www.nhlbi.nih.gov/whi/
• (2)Brown, Ann J., M.D. Hormone Replacement Therapy & Menopause, Duke University Medical Center.
• (3)O'Grady, Lois et al, A Practical Approach to Breast Disease, Boston: Little Brown and Company, 1995, 186-187.
• (4)The National Cancer Institute provides information on menopause and HRT at http://cancernet.nci.nih.gov/
• (5)The FDA provides information on HRT at http://www.fda.gov/cder/drug/infopage/estrogens_progestins/default.htm
• (6) The U.S. Agency for Healthcare Research and Quality May 16, 2005 news release, "Task Force Recommends Against Routine Use of Estrogen To Prevent Chronic Diseases in Postmenopausal Women Who Have Undergone Hysterectomy," was published on the agency's website at http://www.ahrq.gov/
• To learn more about menopause, please visit http://www.imaginis.com/womenshealth/menopause.asp
• To learn more about osteoporosis, please visit http://www.imaginis.com/osteoporosis/
• To learn more about heart disease, please visit http://www.imaginis.com/heart-disease/

Updated: January 23, 2008

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