MONDAY, April 14 (HealthDay News) -- Postmenopausal women who
take hormones have a lower risk of developing advanced age-related
macular degeneration, especially if they took oral contraceptives
in the past, a U.S. study finds.
Age-related macular degeneration (AMD) affects 1.75 million
Americans and is a leading cause of vision loss and blindness among
older adults, according to background information in the study.
"Although genetics play a key role in susceptibility to AMD,
environmental factors, such as smoking, are also important," the
researchers wrote. "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 development of the condition, they
added.
The researchers from Brigham and Women's Hospital and Harvard
Medical School in Boston examined data on almost 75,000
postmenopausal women in the Nurses' Health Study. They assessed
estrogen-related factors such as postmenopausal hormone use, past
use of oral contraceptives, ages at first period and menopause, and
childbirth history.
Between 1980 and 2002, 554 of the women developed early AMD, and
334 women developed neovascular (advanced) AMD.
"Currrent postmenopausal hormone users had a notable 48 percent
lower risk of neovascular (involving formation of new blood
vessels) AMD compared with those who had never used postmenopausal
hormones, although risk did not decline linearly with longer
durations of use," the study authors wrote. "Risk was lowest for
postmenopausal hormone users who had used oral contraceptives in
the past."
However, the study found that current hormone users had a 34
percent higher risk of early AMD. There was no link between oral
contraceptive use and early AMD. Women who'd given birth were 26
percent less likely to develop 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." the researchers concluded.
The study was published in the April issue of the journal
Archives of Ophthalmology.
More information
The U.S. National Eye Institute has more about
AMD.
