Alcohol consumption and the risk of age-related macular degeneration: A systematic review and meta-analysis

PURPOSE: To review systematically the evidence currently available on alcohol consumption and the risk of age,related macular degeneration (AMD). DESIGN: Systematic review and meta,analysis of observational studies. METHODS: Seven databases were searched systematically with no limits on the year or language of publication for prospective cohort studies. References identified from pertinent reviews and articles also were retrieved. Two reviewers independently searched the above databases and selected the studies using prespecified standardized criteria. These criteria included appropriate adjustment for age and smoking in the analysis. Of the 441 studies identified initially, five cohort studies met the selection criteria. Data extraction and study quality evaluation were performed independently by two reviewers and results were pooled quantitatively using meta-analytic methods. RESULTS: The five cohort studies included 136,946 people, among whom AMD developed in 1923 (1,513 early and 410 late). Pooled results showed that heavy alcohol consumption was associated with an increased risk of early AMD (pooled odds ratio, 1.47; 95% confidence interval, 1.10 to 1.95), whereas the association between heavy alcohol consumption and risk of late AMD was inconclusive. There were insufficient data to evaluate a dose-response association between alcohol consumption and AMD or the association between moderate alcohol consumption and AMD. CONCLUSIONS: Heavy alcohol consumption (more than three standard drinks per day) is associated with an increased risk of early AMD. Although this association seems to be independent of smoking, residual confounding effects from smoking cannot be excluded completely.