12 ก.ย. Increased calcium intake associated
Increased calcium intake associated with lower risk of progression to late AMD
A study reported on March 21, 2019 in JAMA Ophthalmology found an association between greater intake of calcium and a lower risk of progression to late age-related macular degeneration (AMD) among participants in the Age-Related Eye Disease Study (AREDS), which evaluated the effects of nutritional supplements on cataracts and AMD from 1992 to 2001. Late AMD is a stage of AMD characterized by vision loss, and includes geographic atrophy (dry) AMD, which involves a breakdown of light-sensitive cells in the macula and neovascular (wet) AMD, which involves new blood vessel growth.
The study included 4,751 AREDS participants with intermediate AMD, late AMD in one eye, or no AMD upon enrollment, who were followed until 2005. Calcium intake from food and supplements was calculated from responses to questionnaires. Eye examinations were conducted at the beginning of the trial and twice yearly until its conclusion, following which the subjects were examined yearly through the follow-up period.
Among those whose intake of calcium from food was among the top 20% of participants, there was a 27% lower risk of developing late AMD in comparison with subjects whose intake was among the lowest 20%. When calcium supplementation was evaluated, participants whose intake was among the top one-third had a 30% lower risk of developing neovascularization than those who did not use calcium supplements. Among women, the risk of developing neovascular AMD was 33% lower among the top third compared to those who did not use calcium supplements. (There were not enough men in the study who used calcium supplements to permit an accurate analysis.)
“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,” Alanna K. Tisdale, MD, MPH, and colleagues conclude.