Calcium Intake Does Not Affect AMD Risk

Emily Chew, MD

There is no evidence of risk linking eating a calcium-rich diet or taking calcium supplements and age-related macular degeneration (AMD), according to a new report.

Investigators from the National Eye Institute, a division of the National Institutes of Health (NIH), conducted a secondary analysis of the Age-Related Eye Disease Study (AREDS) in order to evaluate the association of baseline dietary and supplementary calcium intake with the progression of AMD. AREDS was conducted between 1992 and 2001, and enrolled 4751 patients from academic and community retinal practices in the US.

The average follow-up period was 10 years. Patients reported their own calcium intake using a questionnaire about their diets and supplements. The investigation included men and women of varying AMD disease severity in their analysis, which took place from September 2015 to December 2018. Nearly all the patients were white.

Study authors wrote that previous literature on the subject had mixed results about the effect of dietary and supplementary calcium intake—supplementary intake and decreased dietary intake were both harmful, according to the publications. Thus, a secondary analysis was needed.

Calcium supplements can build strong bones and teeth and are commonly used to prevent and treat osteoporosis. In the US, about 50% men and 65% of women use calcium supplements. The recommended daily amounts of calcium supplements are 1000 mg for adults aged 50 years or younger, and 1200 mg for adults older than 50.

The investigators examined development of late AMD, geographic atrophy (categorizing it as central or noncentral), or neovascular AMD detected on a centrally graded baseline and annual fundus photographs.

Compared to the patients categorized in the lowest quintile of dietary calcium intake, those in the highest quintile had a lower risk of developing late AMD, the study authors determined. Additionally, these patients had a lower risk of developing central geographic atrophy, and any geographic atrophy.

The patients in the highest tertile of supplementary calcium intake showed a lower risk for developing neovascular AMD compared to those who did not take calcium supplements, investigators determined.

“Given the fact that the data up to this point had been mixed on the question of calcium intake and AMD risk, physicians who had reservations about recommending a calcium-rich diet or supplements for osteoporosis prevention and treatment may be reassured by the fact that we found no evidence of risk associated with high calcium intake and AMD,” study author Emily Chew, MD, told MD Magazine®, adding that none of the team’s findings were particularly surprising.

Women in the highest quintile of dietary calcium intake seemed to have a lower risk of developing late AMD compared to those in the lowest quintile. And women with the highest intake of calcium supplements had a lower risk of progression to neovascular AMD compared to patients who did not take calcium supplements.

These findings were similar among male patients, the study authors added. However, they wrote that too few men took calcium supplements to permit a thorough analysis.

Chew added in a statement that “these latest findings provide no evidence that there is a need to change the management of calcium intake for individuals who are already taking calcium for other medical indications.”

These findings seem to support the theory that calcium has a protective role in AMD.

The study, “Association of Dietary and Supplementary Calcium Intake With Age-Related Macular Degeneration: Age-Related Eye Disease Study Report 39,” was published online in JAMA Ophthalmology.