No Causal Association between Insomnia and Gout: A Bidirectional Two-Sample Mendelian Randomization Study

Purpose: Previous observational studies have suggested an association between insomnia and gout. However, the causal nature of this relationship remains uncertain. This study aimed to investigate the bidirectional causal association between insomnia and gout using a Mendelian randomization (MR) analysis. Methods: A bidirectional two-sample MR analysis was conducted utilizing genome-wide association study (GWAS) summary data for insomnia and gout. Single-nucleotide polymorphisms (SNPs) significantly associated with insomnia and gout were used as instrumental variables. Causal effects were estimated using the inverse variance weighted (IVW) method, MR-Egger, and weighted median. Sensitivity analyses were then performed to assess potential pleiotropy and heterogeneity. Results: The MR analysis revealed no significant causal relationship between insomnia and the risk of gout (IVW OR=1.300, 95%CI:0.566-2.986, P=0.537). Similarly, reverse MR analysis showed no causal effect of gout on the risk of insomnia (IVW OR=1.005, 95%CI:0.999-1.011, P=0.099). The findings were consistent across all sensitivity analyses, with no evidence of horizontal pleiotropy or heterogeneity (P>0.05). Conclusion: This study found no evidence supporting a causal relationship between insomnia and gout in either direction. These findings suggest that previous associations observed in observational studies might be confounded by other factors. Further research using larger sample sizes and diverse populations is warranted to validate these results.