Association between postpartum depression and components of the metabolic syndrome: A bidirectional Mendelian randomization study.

To investigate the causality between metabolic syndrome (MetS) components and postpartum depression (PPD) using Mendelian randomization (MR) analysis. Genetic instruments for MetS components including hypertension, fasting blood glucose (FBG), waist circumference (WC), high-density lipoprotein cholesterol (HDL-C), and triglycerides were obtained from public genome-wide association studies. The datasets for PPD data were sourced from the FinnGen study. Univariable and multivariable MR analyses were conducted to assess the causal associations between MetS components and the risk of PPD. The primary analysis employed the Inverse Variance Weighted method, and sensitivity analyses were used to evaluate the robustness of the results. Univariable MR analysis revealed that genetically predicted hypertension (odds ratio [OR] 1.48, 95% confidence interval [CI] 1.04-2.09, P = 0.028) and WC (OR 1.18, 95% CI 1.01-1.38, P = 0.041) were positively associated with an increased risk of PPD, while FBG (OR 0.69, 95% CI 0.54-0.88, P = 0.002) was inversely associated with PPD. Reverse MR analysis suggested a negative causal relationship between PPD and HDL-C (OR 0.96, 95% CI 0.94-0.99, P = 0.006). Multivariable MR analysis further confirmed that hypertension was the primary causal factor for PPD. This MR study provides evidence for a causal relationship between MetS components, particularly hypertension, and the risk of PPD. These findings highlight the importance of addressing MetS factors in the prevention and management of PPD.