Causal relationship between diabetic retinopathy and schizophrenia: A two-sample Mendelian randomization study

Objective: To analyze the causal relationship between diabetic retinopathy and schizophrenia by Mendelian randomization. Methods: A genome-wide association study was designed to probe the association about diabetic retinopathy and schizophrenia. Inverse variance weighting (IVW) method was used for analysis, MR-PRESSO was used for outlier detection, and the robustness of the findings was confirmed by sensitivity analysis. Results: 5 SNPs were finally included, and no outlier SNPs were found by MR-PRESSO, P=0.147 (>0.05). It is showed that there was a causal association between diabetic retinopathy and schizophrenia (β=-0.38, Se=0.18, P=0.03). Furthermore, with the decrease of diabetic retinopathy, it may increase the risk of schizophrenia (OR=0.68;95%CI:0.48-0.96). Horizontal pleiotropy was assessed by sensitivity analysis using the intercept term of the MR-Egger method, which showed P=0.80 (>0.05), indicating that the selected instrumental variables were reliable. Cochran's Q-test was indicated that no heterogeneity among the selected instrumental variables P=0.23 (>0.05). Conclusion: There is a potential causal relationship between diabetic retinopathy and schizophrenia, and these findings provide new ideas for the prevention of schizophrenia.