No causal association between serum vitamin D levels and diabetes retinopathy: A Mendelian randomization analysis

Background and aim: Diabetes retinopathy (DR) is a common microvascular complication of diabetes, and it is the main cause of global vision loss. The current observational research results show that the causal relationship between Vitamin D and DR is still controversial. Therefore, we conducted a Mendelian randomization study to determine the potential causal relationship between serum 25-hydroxyvitamin D 25(OH)D and DR. Methods and results: In this study, we selected aggregated data on serum 25(OH)D levels (GWAS ID: ebi-a-GCST90000615) and DR (GWAS ID: finn-b-DM_RETINOPATHY) from a large-scale GWAS database. Then use MR analysis to evaluate the possible causal relationship between them. We mainly use inverse variance weighted (IVW), supplemented by MR Egger and weighted median methods. Sensitivity analysis is also used to ensure the stability of the results, such as Cochran 's Q -test, MR-PRESSO, MR -Egger interception test, and retention method. The MR analysis results showed that there was no signi ficant causal relationship between 25(OH)D and DR (OR = 1.0128, 95%CI=(0.9593,1.0693), P = 0.6447); Similarly, there was no signi ficant causal relationship between DR and serum 25 (OH) D levels (OR = 0.9900, 95% CI=(0.9758,1.0045), P = 0.1771). Conclusion: Our study found no signi ficant causal relationship between serum 25(OH)D levels and DR, and vice versa. A larger sample size randomized controlled trial is needed to further reveal its potential causal relationship. (c) 2024 The Author(s). Published by Elsevier B.V. on behalf of The Italian Diabetes Society, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition and the Department of Clinical Medicine and Surgery, Federico II University. This is an open access article under the CC BY -NC -ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).