Genetic evidence strengthens the connection between emotional disorders and TMD-related pain: A two-sample Mendelian randomization study.

Abstract

Objectives: This study aims to evaluate the genetic association between emotional disorders and TMD-related pain through two-sample Mendelian randomization analysis.

Design: Single-nucleotide polymorphisms (SNPs) related to emotional disorders (worry, nerves, or depression) were selected from genome-wide association studies (GWAS) from UK Biobank consortia, and related these to SNPs from FinnGen consortia. The inverse-variance weighted (IVW) was used as the primary effect estimate between emotional disorders and TMD-related pain, and various methods were applied to test the reliability and stability of the results, namely MR-Egger and weighted median.

Results: The Mendelian randomization analysis showed that there was a positive correlation between emotional disorders and TMD-related pain, including worry group (IVW odds ratio (OR) = 3.86, 95 % confidence interval (CI) = 1.67-8.91), nerves group (IVW OR = 11.20, 95 % CI=2.04-61.64) and depression group (IVW OR = 3.32, 95 % CI=1.24-8.90). MR-Egger intercept and MR-PRESSO global test did not suggest evidence of horizontal or directional pleiotropy. Cochran's Q test showed that there was no heterogeneity between instrumental variables.

Conclusions: This study provides genetic evidence that strengthens the connection between emotional disorders and TMD-related pain, which has important implications at the causal level as well as throughout the treatment process of TMD-related pain.