Exploring the causal relationships between type 2 diabetes and neurological disorders using a Mendelian randomization strategy

While there is ample evidence indicating an increased occurrence of general neurological conditions among individuals with diabetes, there has been limited exploration into the cause-and-effect connection between type 2 diabetes (T2D) and specific neurological disorders, including conditions like carpal tunnel syndrome and Bell's palsy. We used Mendelian randomization (MR) approach to investigate the causal effects of T2D on 67 neurological diseases. We primarily utilized the inverse-variance weighted method for the analysis, and also employed the weighted median and MR-Egger methods in our study. To detect and correct potential outliers, MR-PRESSO analysis was used. Heterogeneity was assessed using Cochrane Q-values. The MR analyses found a possible relationship between T2D and a risk increase of 8 diseases at suggestive level of evidence (P < .05). Notably, among the positive findings that met the false discovery rate threshold, nerve, nerve root, and plexus disorders (odds ratio [OR] = 1.11; 95% confidence interval [CI] = 1.08-1.15); neurological diseases (OR = 1.05; 95% CI = 1.03-1.07) and carpal tunnel syndrome (OR = 1.10; 95% CI = 1.05-1.16) were identified. Our findings affirm a cause-and-effect association between T2D and certain neurological disorders.