Apr. 17, 2008 Women who take postmenopausal hormones appear to have a lower risk of developing advanced stages of the eye disease age-related macular degeneration, especially if they had also taken oral contraceptives in the past, according to a new report.
Age-related macular degeneration (AMD) is the leading cause of vision loss and blindness among older adults, affecting 1.75 million Americans, according to background information in the article. "Although genetics plays a key role in susceptibility to AMD, environmental factors, such as smoking, are also important," the authors write. "Evidence of higher rates of AMD in women than in men and links between AMD and cardiovascular disease suggested a role for estrogen in the etiology" or development of the condition.
Diane Feskanich, Sc.D., of Brigham and Women's Hospital and Harvard Medical School, Boston, and colleagues assessed estrogen-related factors such as postmenopausal hormone use, past use of oral contraceptives, ages at first period and menopause and childbirth history in 74,996 post-menopausal women in the Nurses' Health Study. Between 1980 and 2002, 554 of the women developed early (beginning-stage) AMD and 334 women developed neovascular (more advanced, involving the formation of new blood vessels) AMD.
"Current postmenopausal hormone users had a notable 48 percent lower risk of neovascular AMD compared with those who had never used postmenopausal hormones, although risk did not decline linearly with longer durations of use," the authors write. "Risk was lowest for postmenopausal hormone users who had used oral contraceptives in the past."
In contrast, risk of early AMD was 34 percent higher among current postmenopausal hormone users and oral contraceptive use was not associated with early AMD risk. "The higher risk of early AMD among postmenopausal hormone users was unexpected and in apparent conflict with the observed inverse association for neovascular AMD," the authors write. Women who had given birth had a 26 percent lower risk of early AMD.
"Taken together, these findings suggest a role for estrogen in the pathogenesis of AMD that requires further research in specific early and late signs of disease," they conclude.
Journal reference: Arch Ophthalmol. 2008;126:519-524.
This research was supported by grants from the National Institutes of Health.
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