A study published in the Archives of Ophthalmology reports that there is an association between women who take postmenopausal hormones and the risk of developing age-related macular degeneration. Diane Feskanich, Sc.D., (Brigham and Women’s Hospital and Harvard Medical School, Boston) and colleagues found that, especially for women who had taken oral contraceptives, postmenopausal hormones reduced the risk of progressing to advanced stages of the eye disease.
Among older adults, age-related macular degeneration (AMD) is the chief cause of blindness and loss of vision. The condition is responsible for profound vision loss in 1.75 million Americans. “Although genetics plays a key role in susceptibility to AMD, environmental factors, such as smoking, are also important,” write Feskanich and colleagues. “Evidence of higher rates of AMD in women than in men and links between AMD and cardiovascular disease suggested a role for estrogen,” in how the disease develops.
The researchers used data from the Nurses’ Health Study to analyze AMD and factors related to estrogen such as postmenopausal hormone use, oral contraceptive use, ages of menarche (first period) and menopause, and history of childbirth. Of the 74,996 post-menopausal women in the sample, 554 and 334 developed beginning-stage and neovascular AMD, respectively, between 1980 and 2002. The neovascular stage of AMD is more advanced and results in the development of new blood vessels.
The researchers found that, “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. Risk was lowest for postmenopausal hormone users who had used oral contraceptives in the past.”
However, oral contraceptive use was not linked to early AMD risk, and current postmenopausal hormone users were 34% more likely to develop early stage AMD than non-users. “The higher risk of early AMD among postmenopausal hormone users was unexpected and in apparent conflict with the observed inverse association for neovascular AMD,” write the researchers.
In addition, researchers found a 26% lower risk of early AMD among women who had given birth.
The authors conclude that, “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.”
Menopausal and Reproductive Factors and Risk of Age-Related Macular Degeneration
Diane Feskanich, ScD; Eunyoung Cho, ScD; Debra A. Schaumberg, ScD, OD, MPH; Graham A. Colditz, MD, DrPH; Susan E. Hankinson, ScD
Archives of Ophthalmology (2008). 126[4]: 519-524.
Written by: Peter M Crosta