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Original Investigation
March 21, 2019

Association of Dietary and Supplementary Calcium Intake With Age-Related Macular Degeneration: Age-Related Eye Disease Study Report 39

Author Affiliations
  • 1Division of Epidemiology and Clinical Applications, National Eye Institute, National Institutes of Health, Bethesda, Maryland
  • 2Emmes Corporation, Rockville, Maryland
JAMA Ophthalmol. 2019;137(5):543-550. doi:10.1001/jamaophthalmol.2019.0292
Key Points

Question  Is calcium intake associated with age-related macular degeneration (AMD)?

Findings  In secondary analyses of randomized clinical trial participants, baseline calcium intake was found to be associated with AMD; participants with the highest intake of dietary calcium had a lower risk of developing late AMD and geographic atrophy than those in the lowest quintile. The participants in the highest intake of supplementary calcium had a lower risk of developing neovascular AMD compared with those who did not take supplements.

Meaning  Despite these protective associations of dietary and supplementary calcium, the results may be considered hypothesis generating, requiring validation with further investigations.

Abstract

Importance  Previous studies of the role of dietary and supplementary calcium in age-related macular degeneration (AMD) have produced mixed results, suggesting that supplementation and decreased dietary intake are both harmful.

Objective  To evaluate the association of baseline dietary and supplementary calcium intake with progression of AMD.

Design, Setting, and Participants  This study involved secondary analyses of participants enrolled in the Age-Related Eye Disease Study (AREDS). The AREDS study (1992-2001) enrolled patients from academic and community-based retinal practices in the United States. Men and women with varying severity of AMD were included. Data analysis for this article occurred from September 2015 to December 2018.

Exposures  Baseline self-reported dietary or supplementary calcium intake.

Main Outcomes and Measures  Development of late AMD, geographic atrophy (central or noncentral), or neovascular AMD detected on centrally graded baseline and annual fundus photographs.

Results  A total of 4751 participants were included (mean [SD] age, 69.4 [5.1] years); 4543 (95.6%) were white, and 2655 (55.9%) were female. Compared with those who were in the lowest quintile, the participants in the highest quintile of dietary calcium intake had a lower risk of developing late AMD (hazard ratio [HR], 0.73 [95% CI, 0.59-0.90]), central geographic atrophy (HR, 0.64 [95% CI, 0.48-0.86]), and any geographic atrophy (HR, 0.80 [95% CI, 0.64-1.00]). The participants in the highest tertile of supplementary calcium intake had a lower risk of developing neovascular AMD (HR, 0.70 [95% CI, 0.50-0.97]) compared with those who did not take calcium supplements. When stratified by sex, women in the highest quintile of dietary calcium intake had a lower risk of developing late AMD (HR, 0.73 [95% CI, 0.56-0.97]) compared with those in the lowest quintile. Women in the highest tertile of calcium supplementation had a lower risk of progression to neovascular AMD (HR, 0.67 [95% CI, 0.48-0.94]) compared with those who did not take calcium supplements. Similar findings were found in men for dietary calcium. Too few men took calcium supplements to allow for analyses.

Conclusions and Relevance  In this secondary analysis, higher levels of dietary and supplementary calcium intake were associated with lower incidence of progression to late AMD in AREDS participants. The results may be owing to uncontrolled confounding or chance and should be considered hypothesis development requiring additional study.

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