Association Between Dysmenorrhea and Risk of Epilepsy in East Asian Populations: A Bidirectional Two-Sample Mendelian Randomization Study

Dysmenorrhea is associated with epilepsy. Existing evidence is mostly limited to observational studies, which are liable to confounding and bias. This study investigated the causal relevance of dysmenorrhea on epilepsy using Mendelian randomization (MR). We extracted instrumental variants for dysmenorrhea and epilepsy from published genomewide association study data, focusing on individuals of East Asian descent. A comprehensive suite of MR estimations and sensitivity analyses was performed to ensure the robustness of the findings. Each outcome database was analyzed separately in both directions. For dysmenorrhea and epilepsy, 7 and 3 genetic variants respectively were selectively extracted as instrumental variants. The results suggest that dysmenorrhea is causally associated with an elevated risk of epilepsy (inverse variance weighted [IVW]: OR = 1.26; 95% CI [1.07, 1.47]; p = 4.42 × 10−3); conversely, no strong evidence was found to corroborate that epilepsy exerts a causal effect on the incidence of dysmenorrhea (IVW: OR = 1.04; 95% CI [0.82, 1.33]; p = .72). These findings provide novel insights into the causal relationship between dysmenorrhea and epilepsy, which may have implications for clinical decision-making in patients with epilepsy and dysmenorrhea.