HealthNotes

A new study has found an association between calcium supplements and age-related macular degeneration (AMD), although there are important limitations to the results. Published in JAMA Opthalmology, the study looked at data for 3,191 people, ages 40 and older, who took part in the 2007–2008 National Health and Nutrition Examination Survey (NHANES). Participants self-reported their use of calcium supplements and NHANES researchers evaluated the participants for AMD. After adjusting for health and lifestyle factors, researchers found that taking 800 mg daily of supplemental calcium was associated with a higher risk of developing AMD in people who were 68 years and older. However, the results should be viewed with caution for the following reasons:

• The study was observational in nature—not a placebo-controlled clinical trial—and therefore cannot prove a cause-and-effect relationship between calcium supplements and AMD.
• The study did not take into account dietary calcium intake. This is important because it’s possible that some people may have taken calcium supplements to compensate for a diet that was low in calcium, and therefore differences in diet (and not calcium supplements) may have been responsible for the association between calcium and AMD.
• Researchers did not find any association between calcium supplements and AMD in people younger than 68.