Causal Association Between Omega-3 Fatty Acids and Risk of Breast Cancer: A Mendelian Randomization Study

Objective To explore the causal relationship between Omega-3 fatty acids and the risk of breast cancer via Mendelian randomization analysis.

Methods Analysis was conducted on data from genome-wide association studies (GWASs) on Omega-3 fatty acids and breast cancer. The selected instrumental variables (IVs) comprised genetic loci associated with Omega-3 fatty acids. Various Mendelian randomization analysis methods, including inverse-variance weighted (IVW) method, MR–Egger regression analysis, weighted median, simple models, and weighted models, were used to evaluate the causal relationship between Omega-3 fatty acids and the risk of breast cancer.

Results A total of 47 single-nucleotide polymorphisms strongly associated with Omega-3 fatty acids were selected as IVs. The analysis methods, including IVW method, revealed no causal relationship between Omega-3 fatty acids and the risk of breast cancer (P>0.05). Analysis methods, such as MR-Egger regression analysis, did not detect significant gene-level pleiotropy (P=0.319), which indicates the high sensitivity and robustness of analysis results.

Conclusion The findings of this study suggest the absence of a causal relationship between Omega-3 fatty acids and the risk of breast cancer.