Abstract
Purpose :
To evaluate the association of dietary and supplemental calcium intake with progression of age-related macular degeneration (AMD).
Methods :
Age-Related Eye Disease Study (AREDS) participants (n=4751) were retrospectively analyzed for the association of calcium intake and progression to intermediate AMD (large drusen/pigmentary changes) or late AMD (neovascular or geographic atrophy (GA)). Calcium intake (dietary and supplements) was estimated based on responses to a baseline dietary questionnaire. Baseline and annual fundus photographs were graded at a reading center using a standardized protocol to assess the progression of AMD. Analyses were conducted using the Cox regression models with the Wei-Lin-Weissfield technique and adjusted for age, gender, race, smoking, and education. The analyses of the dietary intake were calorie-restricted, from 677 to 1994 kcal and 794 to 2771 kcal, for females and males, respectively.
Results :
AREDS participants (median age: 69 years, 56% female) were followed from 1992 to 2005 (1992 to 2001 as a clinical trial). The participants in the highest quintile of dietary calcium intake had a lower risk of developing AMD than those in the lowest quintile: late AMD (HR: 0.73, 95%CI: 0.59, 0.90), central GA (HR: 0.65, 95% CI: 0.48, 0.88), and neovascular AMD (HR: 0.78, 95% CI, 0.61, 1.00). The participants in the highest tertile of supplementary calcium intake had a lower risk of developing neovascular AMD when compared with those who did not take calcium supplements (HR: 0.68 95 %CI: 0.48, 0.95). When stratified by gender, women in the highest quintile of dietary intake of calcium had a lower risk of development late AMD (HR: 0.73, 95% CI: 0.56, 0.97) compared with those in the lowest quintile. The highest tertile of calcium supplementation in women was associated with the reduction in the progression to neovascular AMD (HR: 0.68, 95% CI: 0.48, 0.96) compared with those in the lowest tertile. Similar findings were found in men for dietary calcium while too few men took calcium supplements to allow for analyses.
Conclusions :
In the AREDS participant population, higher levels of dietary and supplementary calcium intake were associated with a lower incidence of progression to late AMD. This association warrants further investigation.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.