Employing Bidirectional Two-Sample Mendelian Randomization Analysis to Verify the Potential of Polyunsaturated Fatty...

Polyunsaturated fatty acids (PUFAs), specifically Omega-3 (FAω3) and docosahexaenoic acid (DHA), have been studied for their potential role in modulating pancreatic cancer (PC) risk. Although observational studies suggest a beneficial effect in reducing this risk, their findings are often limited by confounding variables and issues of reverse causation. This study used a two-way two-sample Mendelian randomization (MR) method to test the hypothesized genetic causal relationship between PUFAs and PC risk. Data from an extensive genome-wide association study (GWAS) were analyzed, focusing on FAω3 and FAω6 levels, their ratios, and DHA as variables and PC incidence as outcomes. This relationship was comprehensively evaluated using related MR methods, such as inverse variance weighting (IVW), MR Egger, and weighted median (WM). This study finds a significant negative correlation between FAω3 and DHA levels and PC risk, while FAω6 levels show no significant correlation. Interestingly, the ratio of FAω6 to FAω3 was positively associated with increased risk of PC. Neither the MR Egger nor the MR-PRESSO tests detected significant pleiotropy, nor did the Cochrane's Q test show significant heterogeneity. Leave-one-out analyzes further confirmed the robustness of these results. Using MR analysis of two samples, this study provides genetic causal evidence that FAω3 and DHA levels reduce the risk of PC, whereas the ratio of FAω6 to FAω3 increases the risk of PC. These insights highlight the potential utility of supplementing FAω3 and DHA or altering PUFAs in developing PC prevention strategies.