Exploring the link between dietary patterns and gastric adenocarcinoma in Brazil: a mediation analysis

Background: The causal pathway between different dietary patterns (DPs) and gastric adenocarcinoma (GA) remains largely unexplored. The study aimed to identify DPs and evaluate how selected nutrients mediate the relationship between DPs and GA. Methods: This multicenter case–control study in Brazil involved 1751 participants (600 cases, 377 endoscopic controls, and 774 hospital controls). DPs were identified through exploratory factor analysis. A counterfactual-based mediation analysis was performed to decompose the total effect of DPs on GA into direct and indirect effects mediated by saturated fatty acids, added sugars, total fiber, and sodium intakes. Effects were expressed as ORs and 95% CIs. Results: Two DPs were identified—“unhealthy dietary pattern” (UDP) and “healthy dietary pattern” (HDP), which were associated with an increased and decreased risk of GA, respectively. Added sugars partly mediated the association between UDP and GA (percentage mediated between 7.3 and 21.7%), while sodium intake mediated most of the association between HDP and GA (percentage mediated between 52.4 and 100%). No significant mediating effects were detected for saturated fatty acids and total fiber. Conclusions: This study contributes innovative insights into the DPs-GA relationships, highlighting the significant mediating roles of sodium and added sugars, offering valuable information for preventive strategies and public health interventions targeting GA. Graphical Abstract: (Figure presented.)