Eyeworld

117 EW RETINA March 2016 In addition, investigators took it a step further to see if the associ- ation between vitamin D and AMD varied depending on an individual's genetic risk for AMD. Dr. Millen and co-authors examined the vitamin D and AMD association in women with differing levels of genetic risk defined by the Y402H variant of the gene complement factor H. "In women who had low D and 2 alleles for the high-risk gene variant, there was about a 6-fold increased chance of AMD compared to women who had adequate vitamin D levels and no high risk alleles for complement factor H," Dr. Millen said. Scientists hypothesize that the body mounts a localized immune response to drusen. "If the partici- pant is not sufficient in D, it might impede the body's ability to dampen that immune response in the eye," Dr. Millen said. "A localized inflam- matory response to drusen is not healthy for the eye. We speculate that maintaining a healthy vitamin D status may help individuals with AMD control that immune response that (otherwise) could lead to fur- ther damage." The take-home message here is for those who have low vitamin D status: A deficient vitamin D status could be related to increased odds of developing AMD, Dr. Millen report- ed, adding that for those who are already genetically at high risk, this association may be even stronger. "This is just another bit of evidence suggesting that nutrition is import- ant to eye health," she said. "But it's hard in an observational study to tease out or control for the many lifestyle factors that are also related to vitamin D levels—so someone with high D status probably has a healthy diet and is physically ac- tive." Investigators here tried to adjust for this, but Dr. Millen acknowledged that there is always some residual confounding or im- perfect adjustment that may exist. Overall, Dr. Millen views the results here as important for the future. "I think it's exciting and provocative, but I think that we have a lot of work to do before we head into clinical trials," she said. "But it makes biologic sense, and I think the hypothesis is intriguing." From a clinical perspective, she con- cluded that it seems as if low levels of vitamin D could be detrimental when it comes to AMD; howev- er, above the deficient threshold, increasing these levels may not be beneficial. EW Reference 1. Millen AE, et al. Association between vitamin D status and age-related macular degeneration by genetic risk. JAMA Ophthalmol. 2015;133(10):1171–9. Editor's note: Dr. Millen has no finan- cial interests related to her comments. Contact information Millen: aemillen@buffalo.edu " I think it's exciting and provocative, but I think that we have a lot of work to do before we head into clinical trials. But it makes biologic sense, and I think the hypothesis is intriguing. " –Amy Millen, PhD On continued from page 114

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