Genetic causal association between type 2 diabetes, body mass index, smoking initiation and myopia：A mendelian randomization study

Abstract

The purpose of this investigation was to explore the causal relationships between type 2 diabetes, body mass index(BMI), smoking initiation, and myopia. We utilized summary statistics from independent genome-wide association studies to examine the causal linkages among these factors. Our main analytical technique was the inverse-variance-weighted (IVW) method, along with weighted median and mr-egger as supplements. Univariable and multivariable mendelian randomization(MR) analyses were conducted, and reverse MR was performed to assess reverse causation.The results showed that there were associations between myopia and smoking initiation (odds ratio (OR) 0.984, 95% confidence interval (CI) 0.977-0.992, p=6.35×10-5), body mass index (OR 0.989, 95% CI 0.984-0.993, p=3.84×10-6), and type 2 diabetes (OR 1.004, 95% CI 1.002-1.006, p=4.15×10-4). These associations remained strong even after mutual adjustment. We observed no pleiotropy in these exposures, and no associations were found in reverse MR.In conclusion, this study is the first to use univariable and multivariate mendelian randomization to confirm a causal relationship between type 2 diabetes, smoking initiation, BMI and myopia.