Relationship between vitamin D deficiency and diabetic retinopathy: a meta-analysis

Abstract Objective The purpose of this study was to evaluate the evidence for an association between diabetic retinopathy (DR) and vitamin D deficiency. Design Meta-analysis. Methods We included 14 observational studies with 10 007 participants who had undergone assessment for both DR and vitamin D deficiency. Pooled odds ratios (ORs) and 95% CIs were calculated using a random-effect, Mantel–Haenszel analysis. Results There was a statistically significant association between DR and vitamin D deficiency with an overall pooled OR of 1.27 (95% CI, 1.17–1.37; P = 0.001; I2 = 80%; Pheterogeneity = 0.01). There was also a statistically significant lower serum vitamin D level in patient subgroups with DR versus control groups, with an overall mean difference of –1.32 ng/mL (95% CI, –2.50 to –0.15; P = 0.001; I2 = 89%; Pheterogeneity = 0.01). Conclusion There is a statistically significant association between vitamin D deficiency and DR.