Maternal smoking around birth and psychiatric disorders of offspring: A Mendelian Randomization Study

Abstract Objective: To investigate the causal effect of maternal smoking around birth on the risk of four psychiatric disorders in offspring using Mendelian randomization (MR); Methods Genome-wide association studies (GWAS) data were extracted from published data on maternal maternal smoking around birth and four psychiatric disorders, including attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), bipolar disorder (BD) and major depressive disorder (MDD). Inverse variance weighting (IVW), weighted median (WM), and MR-PRESSO methods were applied, and a comprehensive MR analysis and sensitivity analysis were conducted to explore the causal relationship between maternal smoking around birth and the risk of developing the four psychiatric disorders, using the dominance ratio (OR) as an evaluation index; Results Smoking before and after delivery was associated with ADHD (IVW: OR=12.299, 95% CI=3.341-45.27, P<0.001) and MDD (IVW: OR=5.789, 95% CI=2.576-13.011, P<0.001); Conclusion Our study is based on genetic data, revealing a potential causal relationship between maternal smoking before and after birth and the incidence of attention deficit hyperactivity disorder and severe depression in offspring.