To evaluate the bidirectional causal relationship between emotional swing and colorectal cancer using Mendelian randomization,and to test the causal regulatory effect of emotional swing on lipid metabolism.

Using summary data from genome-wide association studies,we selected genetic variants associated with emotional swing, colorectal cancer,total cholesterol,and triglycerides as instrumental variables.A bidirectional Mendelian randomization design was applied to assess causal associations in both directions between emotional swing and colorectal cancer.The inverse variance weighted method served as the primary analysis,supplemented by weighted median and MR-Egger regression for sensitivity analysis.We also tested the individual effects of total cholesterol and triglycerides as potential mediators.

Forward causal analysis detected only a marginal negative association between emotional swing and colorectal cancer using inverse variance weighting(OR=0.981),suggesting insufficient robustness.Reverse causal analysis found no significant causal effect of colorectal cancer on emotional swing(OR=0.839).Further analysis revealed that emotional swing exerted opposite causal effects on the two lipid indicators:a negative causal relationship with total cholesterol(OR=0.688) and a positive causal relationship with triglycerides(OR=1.797),with stable results.

There is no robust bidirectional causal relationship between emotional swing and colorectal cancer,but emotional swing participates in disease progression through differential regulation of total cholesterol and triglycerides.Given the potential value of medicinal and edible resources of Shanxi in intervening in the emotion-metabolism-cancer axis,we recommend incorporating lipid metabolism indicators into comprehensive colorectal cancer risk management and exploring pathways for industrializing non‑nutrient components in community prevention and treatment.