Abstract
Purpose::
To examine incidence of age-related macular degeneration (AMD) in a randomized trial of folic acid/vitamin B6/vitamin B12.
Methods::
The Women's Antioxidant and Folic Acid Cardiovascular Study was a randomized, double-blind, placebo-controlled trial of antioxidant vitamins and a folic acid/vitamin B6/vitamin B12 combination in the prevention of cardiovascular (CVD) events among female health professionals aged 40 years or older with preexisting CVD or 3 or more CVD risk factors. A total of 8,171 women were randomized to vitamin E, vitamin C, beta carotene, or placebos. Of these, 5,442 women were also subsequently randomized to folic acid (2.5 mg/d), vitamin B6 (50 mg/d), and vitamin B12 (1 mg/d), or placebo; 5,205 of these women did not have a diagnosis of AMD at baseline and were included in this analysis. Main outcome measures were confirmed AMD, defined as a self-report supported by medical record evidence of an initial diagnosis subsequent to randomization, and AMD with vision loss, defined as confirmed AMD with vision to 20/30 or worse attributable to this condition.
Results::
During an average of 7.3 years of treatment and follow-up, a total of 137 cases of AMD were documented, including 69 cases responsible for vision loss to 20/30 or worse. For the endpoint of confirmed AMD, there were 55 cases in the folic acid/B6/B12 group and 82 in the placebo group (relative risk [RR], 0.66; 95% confidence interval [CI], 0.47-0.93; p=0.02). For AMD with vision loss, there were 26 cases in the folic acid/B6/B12 group and 43 in the placebo group (RR, 0.60; 95% CI, 0.37-0.98; p=0.04).
Conclusions::
These randomized trial data from a large cohort of women with CVD indicate that seven years of daily supplementation with folic acid/B6/B12 may reduce the risk of AMD.
Clinical Trial::
www.clinicaltrials.gov NCT00000161
Keywords: age-related macular degeneration • clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials • nutritional factors