Causal relationship between sleep traits and risk of Epilepsy: A Mendelian randomization study.

Background: Observational studies have identified a strong correlation between epilepsy and sleep traits, highlighting their interactive relationship. However, no studies have specifically examined the associations between sleep traits and epilepsy. In this context, we conducted a Mendelian Randomization (MR) investigation to explore the causal nature of these associations.

Methods: We performed a two-sample Mendelian Randomization (MR) analysis model to genetically predict the causal effects of morning chronotype on epilepsy. Five MR analysis methods were conducted to analyze the final results. The inverse-variance weighted (IVW) method was used as the primary outcome. The other MR analysis methods (MR-Egger; Weighted Mode; and Weighted median (WM)) were conducted as the complement to IVW. In addition, the robustness of the MR analysis results was assessed by leave-one-out analysis.

Results: In forward MR, epilepsy showed causal relationships with sleep duration (IVW beta = 0.008, P = 0.015). Specifically, doubling the odds of inheriting epilepsy may be associated with a 0.0075 standard deviation (SD) (95 % CI: 1.001 to 1.014) increase in sleep duration. In reverse MR, we found statistically significant associations between chronotype (evening preference) (OR = 1.397, p = 0.007) and insomnia (OR = 2.280, p = 0.025) and the risk of epilepsy.

Conclusion: Our two-sample Mendelian randomization analyses indicate that individuals with epilepsy frequently experience extended sleep duration. Additionally, we identified insomnia and chronotype (evening preference) as significant risk factors that increase the likelihood of developing epilepsy.