Secondary analyses of participants of the Age-Related Eye Disease Study (AREDS) have revealed that those with noticeably increased dietary calcium intake had a lower risk of developing late age-related macular degeneration (AMD) and geographic atrophy (GA) of any kind. Also, participants with consistent supplementary calcium intake had a lower risk of developing neovascular AMD  compared with those who did not take calcium supplements.

Researchers in Maryland retrospectively investigated the AREDS for associations of dietary and supplemental calcium with the risk of AMD development and progression to intermediate AMD, late AMD, wet AMD or GA development, whether any GA or central GA. After comparing participants (n=778) with the highest level of dietary calcium intake to those with the lowest level (n=839), researchers found a reduced risk of developing late AMD and any GA. Participants in the highest level of self-reported calcium supplementation (n=277) had a lower risk of developing neovascularization than those who did not take calcium supplements (n=4,064). Subjects with the highest amount of self-reported calcium supplementation compared with those who did not take supplements did not have different risks of developing large drusen.

The study also found dietary intake of calcium was highly associated with increased lutein intake but not with increased fish intake. Researchers suggested that the association of dietary or supplemented calcium with the later stages of AMD development might simply reflect other health habits of this population. Nevertheless, the study found no evidence that calcium intake might be harmful in the development of AMD.