April 14, 2008 -- There is growing evidence that hormone therapy may help protect older women against the leading cause of age-related blindness, but the findings should not change the current view that hormones should only be used to treat the symptoms of menopause, experts say.
In a new analysis from the large, ongoing Nurses' Health Study, researchers reported that taking postmenopausal hormones appeared to significantly lower the risk for developing the advanced stage of age-related macular degeneration (AMD).
Current hormone users were found to have a 48% lower risk for developing the neovascular, or wet, form of AMD, compared with women who had never taken postmenopausal hormones.
"Our finding of a lower risk of the neovascular form of AMD in postmenopausal women is consistent with several other studies," researcher Diane Feskanich, ScD, tells WebMD.
Findings From the Women's Health Initiative
Similar results were reported two years ago from the Women's Health Initiative (WHI), the study that first raised concerns about an increased risk for strokes and breast cancer associated with long-term, postmenopausal hormone therapy use.
Those 2002 findings abruptly led to the abandonment of hormone therapy for the prevention of disease. It is now recommended that for the treatment of hot flashes and other menopause symptoms women should take the lowest effective dosage for the shortest possible time.
WHI data reported in 2006 also suggested a protective benefit for hormone therapy against neovascular age-related macular degeneration in older women.
But WHI researcher Mary N. Haan, MPH, DrPH, tells WebMD that the findings do not mean that hormones should be revisited for disease prevention.
"Neovascular AMD is actually pretty rare, while stroke and breast cancer are common in postmenopausal women," she says. "When you consider all the evidence, the risks of long-term treatment still outweigh the benefits."
No Protection Against Early AMD
Neither study showed a protective benefit for hormone therapy against early-stage age-related macular degeneration.
The newly reported Nurses' Health Study, which included nearly 75,000 postmenopausal women followed between 1980 and 2002, showed a 34% higher risk for early AMD among hormone users, compared to nonusers.
The study appears in the April issue of Archives of Ophthalmology.
"This finding was certainly not expected, and we couldn't really explain it," Feskanich says. "It may be that women who take hormones may be seeing their doctors more often, leading to earlier diagnosis. But our data didn't show that."
Feskanich says more study is needed to explain the apparent contradiction between the findings for early- and late-stage disease.