High Calcium Intake May Slow Progression of AMD
JAMA Ophthalmology, May 2019
Studies of the effect of calcium intake on age-related macular degeneration (AMD) have produced conflicting results. In a secondary analysis of patients in the Age-Related Eye Disease Study (AREDS), Tisdale et al. evaluated the relationship between baseline calcium intake and the progression of AMD. They found that higher levels of dietary and supplementary calcium were linked to lower likelihood of progression to late AMD.
Baseline self-reported intake of dietary and supplementary calcium was documented during AREDS, then analyzed in relation to outcomes. The main outcome was the occurrence of late AMD, geographic atrophy (GA), or neovascular AMD. The 4,751 participants were predominately white (96%) and female (56%); their mean age was 69.4 years.
Compared with patients in the lowest quintile for dietary calcium intake, those in the highest quintile had a lower risk of late AMD (hazard ratio [HR], 0.73), central GA (HR, 0.64), and any GA (HR, 0.80). The risk of neovascular AMD was lower for patients in the highest tertile for calcium supplementation (HR, 0.70) than for those who did not take supplements. No adverse effects were noted.
Although the findings indicate that dietary and supplemental calcium may aid in protecting against late AMD, the authors acknowledged that chance, uncontrolled confounding, and recall bias might have contributed to the results, and they noted that increased calcium intake could simply reflect better overall health habits. They encouraged further investigation of the topic. (Also see related commentary by Mårten E. Brelén, BMBCh, FRCOphth, PhD, Danny S. Ng, FRCS, MPH, and Carol Y. Cheung, PhD, in the same issue.)
The original article can be found here.