A study released Tuesday adds to the health risks of hormone replacement therapy for post-menopausal women because it concludes the medications can double the risk of dementia and Alzheimer’s disease.
Hormones such as estrogen and progestin long have been used to alleviate postmenopausal symptoms and many physicians have continued to prescribe them for older women because they remain convinced the medications ward off heart disease and dementia. But a study released last year called the Women’s Health Initiative revealed the hormones actually increased the risk of heart disease, as well as breast cancer.
Now a new analysis of that same data, called the Women’s Health Initiative Memory Study, shows the hormones also increase the risk of dementia in women over age 65.
The study “found that older women taking combination hormone therapy have twice the risk of dementia than women who did not take the medications,” the study’s principal investigator Sally Shumaker, of Wake Forest University School of Medicine in Winston-Salem, N.C., said during a conference call from Bethesda, Md.
“For older women at least the risks for combination therapy clearly outweigh the benefits,” Shumaker said. She noted the findings cannot be extrapolated to younger women because they were not included in the analysis. “They really do apply to women 65 and older,” she said.
The findings might be a shock to many researchers because some previous studies had indicated estrogen and progestin decrease the risk of Alzheimer’s.
“Although the results of the WHIMS trial are disappointing, it does provide us with additional information that women can use to make informed choices about estrogen and progestin therapy,” said Dr. Judith Salerno, deputy director of the National Institute on Aging, a component of the National Institutes of Health.
The Food and Drug Administration emphasized the hormones were safe for short-term use for alleviating postmenopausal symptoms, such as hot flashes and night sweats.
“We recommend women continuously consider their options regarding hormone replacement therapy and consider taking it for the shortest time possible,” said Lisa Rarick of the FDA’s Office of Women’s Health.
Hormone replacement therapy still can be appropriate for prevention of osteoporosis, but a woman should discuss with her physician why she is taking the medication, Rarick said. The FDA would not recommend HRT for prevention of heart disease or dementia, she noted.
The FDA also might change the labeling of hormone medications to reflect this new information. “We’ll be reviewing the data from the WHIMS” because these new findings “would likely be appropriate to place in labeling,” Rarick said.
The WHIMS, which appears in the May 28 issue of the Journal of the American Medical Association, analyzed data from about 4,500 women 65 or older who did not have dementia at the time they enrolled in the trial. Over a five-year period those taking the hormones showed about twice the rate of dementia as women taking inactive placebo pills.
The women took one pill per day of Prempro, a commonly used combination medication consisting of estrogen and progestin. Wyeth, the pharmaceutical company that manufactures Prempro, funded the study.
Of the 61 dementia cases diagnosed in the women, 40 of the cases or 66 percent occurred in the women taking the hormones and 21 cases or 34 percent in women taking the placebo. Most of the dementia cases were Alzheimer’s disease. The second most common type of dementia seen in the women was vascular dementia.
If these numbers were extrapolated out to 10,000 women, the hormones would account for about 23 cases of additional dementia each year, Shumaker’s team said.
Shumaker added that the study was not set up to determine how the hormones might cause dementia, so at this stage the mechanism of how the drugs might induce the condition is unclear.
A second study in the same issue of JAMA found the hormones might have a negative impact on the general cognitive function of older women as well. The women took an annual test of cognitive function, called the modified mini-mental state exam, and their scores on the test improved each year as they became more familiar with the test. However, women taking the hormone therapy had a lower rate of improvement on the test than women taking placebo.