Causal Relationship between Omega-6/Omega-3 Fatty Acid Ratio and Risk of Lung Cancer: A Mendelian Randomization Study Base on A European Cohort

This study aimed to elucidate the causal relationship between Omega-6/Omega-3 fatty acid ratio and the risk of lung cancer by using Mendelian randomization (MR) analyses. Omega-6/Omega-3 fatty acid ratio data from the IEU database and lung cancer patient data from the International Lung Cancer Consortium were collected for this MR analyses. Single nucleotide polymorphisms (SNPs) associated with Omega-6/Omega-3 fatty acid ratio were collected as instrumental variables (IVs) with criteria of P < 5E-8, linkage disequilibrium R2 > 0.001 and clump distance < 10,000 kb. We used the inverse variance weighted (IVW) method as the primary method of MR analyses to evaluate the causal relationship between Omega-6/Omega-3 fatty acid ratio and lung cancer risk. Heterogeneity of the analyses was assessed by Cochran's Q test. Horizontal pleiotropy was evaluated by the intercept with the MR-Egger test. 28 SNPs related to Omega-6/Omega-3 fatty acid ratio were selected as IVs in total. The MR analyses results showed that higher Omega-6/Omega-3 fatty acid ratio was associated with lower risk of lung cancer (P = 0.009). No statistical significance was observed for MR-Egger and simple mode methods (P > 0.05). No significant horizontal pleiotropy was detected by MR-Egger regression test (P = 0.73). Conclusion: Higher Omega-6/Omega-3 fatty acid ratio was associated with lower lung cancer risk.