Vitamin intake and glaucoma risk: A systematic review and meta-analysis

There is currently a lack of high-quality research on the best dietary recommendations for patients with early glaucoma or at high risk for glaucoma. This meta-analysis aims to clarify the relationship between vitamin intake and glaucoma risk. Electronic databases, including PubMed, EMbase, ScienceDirect, Cochrane Database, Clinicaltrials.gov, and Google Scholar, were searched for publications indexed as of September 18, 2021. Data were expressed as odds ratios (ORs) with 95% confidence intervals (CIs). The I² index was used to assess heterogeneity. We performed five meta-analyses of existing studies to summarize the evidence on the association between vitamin intake and glaucoma risk. The initial search identified 689 studies, eight of which (262,189 patients) met the eligibility criteria for the meta-analysis. The data showed that high-dose intake of vitamins A (OR=0.63, 95%CI [0.53, 0.76]) and B (OR=0.71, 95%CI [0.64, 0.80]) but not vitamins C (OR=0.69, 95%CI [0.48, 1.01]), D (OR=0.90, 95%CI [0.45, 1.83]), or E (OR=0.91, 95%CI [0.71, 1.16]) was associated with a low prevalence of glaucoma. The results of this study demonstrated that high-dose intake of vitamins A and B, but not vitamins C, D, or E, was associated with a low prevalence of glaucoma.