This analysis of the AREDS formulation of high-dose antioxidants and zinc supplements on AMD progression found that the benefit persisted over 10 years. It reduced the risk of developing wet AMD or advanced AMD, but not central geographic atrophy.
AREDS was an 11-center, double-masked, clinical trial that randomized 4,757 patients with dry AMD to placebo, zinc, antioxidants, or antioxidants plus zinc. After the trial ended in 2001, there was a two-year hiatus, and then 70 percent of the participants resumed the vitamins once they became available in 2003. Of these, 3,549 patients were followed until 2005.
For patients with at least intermediate dry AMD (categories 3 and 4), researchers found that antioxidants plus zinc decreased the risk of wet AMD but not of central geographic atrophy. This formulation also decreased the risk of three or more lines of visual loss. Interestingly, participants randomized to zinc showed a reduction in all-cause mortality, largely related to deaths from diseases of the circulatory system.
The authors note that the AREDS population differs from the general population in several respects: It is better nourished, more highly educated and healthier. Hence, the generalizability of the study’s findings is unknown.
They also note that the treatment effect is relatively modest and AMD and vision loss events continue to occur in participant taking the AREDS formulation. Furthermore, they still do not know for how long someone at risk of advanced AMD should take the supplements. Nevertheless, they continue to recommend the AREDS formulation for those with intermediate or advanced AMD in one eye and for those at moderate to high risk of developing advanced AMD.