Records for 39,421women enrolled in the 10-year Women's Health Study (WHS) were used to evaluate the impact of low-dose aspirin on AMD risk. None of the women had AMD at the study outset; they were randomly assigned to take low-dose aspirin (100 mg on alternate days) or a placebo. It is known that low-dose aspirin substantially reduces the risk of serious blood vessel blockage, so researchers reasoned it might affect blood vessels that may play a role in AMD. Aspirin's anti-inflammatory and anti-oxidant effects were also considered potentially relevant. The research was supported by the National Eye Institute.
"Although our study found no large benefit from low-dose aspirin, the possible modest protective effect we did find warrants further study," said lead researcher William G. Christen, ScD, of Brigham and Women's Hospital, Boston, MA. "If future studies confirm our findings, it could be important to make the public aware of this benefit," he added.
The risk of developing vision-impacting AMD was reduced by18 percent in women who took low-dose aspirin. During the 10 year study, 245 AMD cases developed, 111 in the aspirin group and 134 in the placebo group. "Vision impact" was defined as a reduction in visual acuity to 20/30 or worse due to AMD. Though not statistically significant, the WHS risk reduction is similar to the result of the only other large randomized trial on this question: the Physicians' Health Study I, which followed 22,071 men who took low-dose aspirin or a placebo for five years.
The primary aim of the WHS was to learn whether Vitamin E and low-dose aspirin would help prevent heart disease and cancer. The AMD study also found that women who were not taking multivitamins appeared to benefit more from low-dose aspirin than vitamin users.