Mood swings and risk for cancer: A Mendelian randomization analysis

Background: Despite significant advances in the treatment and prevention of cancer, it remains a leading cause of death globally, imposing a substantial economic burden. In this study, we employed Mendelian randomized studies to explore the causal relationship between mood swings and the risk of cancer. Methods: : We conducted a large-scale genome-wide association study (GWAS) to extract instrumental variables (IVs) that were strongly associated with exposure factors through genetic variation. We used three methods, namely inverse variance weighting (IVW), Weighted median, and MR Egger, to analyze the data and obtain preliminary results. We further used sensitivity analysis to verify the reliability of our findings. We used Cochran's Q value to detect heterogeneity, the MR-Egger intercept test to detect polymorphism and a leave-one-out analysis was conducted to evaluate the impact of removing a single SNP on the results. Results: : Our findings that mood swings are associated with an increased risk of endometrial cancer and ER- breast cancer. Our MR analysis indicates that mood swings are not associated with the risk of ER+ breast cancer, lung cancer, colorectal cancer, bladder cancer, prostate cancer, and ovarian cancer. Conclusion: Our MR study reveals that mood swings increase the risk of endometrial cancer and ER-breast cancer.