MAR 2020

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

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N MARCH 2020 | EYEWORLD | 27 Contact Chew: echew@nei.nih.gov by Maxine Lipner Senior Contributing Writer A calcium-rich diet or taking calcium supplements does not appear to increase the risk of AMD, accord- ing to a study published in JAMA Ophthalmology, 1 contradicting earlier study results, according to Emily Chew, MD. The National Health and Nutrition Exam- ination Survey had previously suggested that calcium might have a harmful effect, 2 spurring further investigation. The more recent study by Tisdale et al. included 4,751 patients who were involved in the randomized Age-Related Eye Disease Study (AREDS) conducted from 1992 to 2001. "This was a post-hoc analysis. We evaluated the data in this association study to see if, at baseline, taking calcium supplements or having a high calcium intake would have any impact on pro- gression to late AMD, as captured in the dietary questionnaire," Dr. Chew said. Investigators found that a high dietary calcium intake was actually associated with a decreased risk of macular degeneration, Dr. Chew reported. Women in particular who had high dietary calcium levels had a lower risk of developing late AMD, and those who had the highest levels of calcium supplementation had a lower risk of progression to neovascular AMD. "Can we say that this would be helpful for treatment? We don't think so because we didn't do a randomized trial," Dr. Chew said. "But the important message is we don't think calcium is going to cause harm to patients." The study should help to forestall concerns about taking calcium. "I think the take-home message is that calcium is safe to people with macular degeneration," Dr. Chew said, pointing out that previous research from the Blue Moun- tains Eye Study had also suggested high calcium intake was associated with reduced macular degeneration. The effect in the study may be more of a health habit, rather than an effect of the calci- um itself. For example, people who have a high intake of calcium also have a high intake of lutein and zeaxanthin, which are known to have a protective effect on AMD. If calcium does have a role in forestalling AMD, it may have to do with the fact that calcium is important in drusen, but the mechanism remains unknown, Dr. Chew said. From a clinical perspective, she hopes that people who are already taking calci- um for other conditions, such as osteopo- rosis, are buoyed by the study results. "I think the message is if you're taking it for other reasons, you're safe to take it," she said. When it comes to staving off macu- lar degeneration, Dr. Chew recommends partaking in other healthy measures. She stressed the need to be physically active and maintaining a healthy diet rich in lutein, which makes up an important part of macular pigment, as well as consum- ing regular helpings of fish, replete with omega-3. Taking AREDS supplements and giving up smoking are other measures in- dividuals can do to help stave off AMD. Study: Calcium supplementation not tied with increased AMD risk About the doctor Emily Chew, MD Director, Division of Epidemiology and Clinical Applications National Eye Institute, National Institutes of Health Bethesda, Maryland References 1. Tisdale AK, et al. Association of dietary and supplementary calcium intake with age-re- lated macular degeneration: Age-Related Eye Disease Study report 39. JAMA Ophthalmol. 2019;137:543–550. 2. Kakigi CL, et al. Self-reported calcium supplementation and age-related macular degen- eration. JAMA Ophthalmol. 2015;133:746–54. Relevant disclosures Chew: None High calcium levels don't appear harmful for those with macular degeneration. Source: Emily Chew, MD RESEARCH HIGHLIGHT

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