Consumption of whole and refined grains and the risk of gastric cancer: a pooled analysis within the Stomach cancer Pooling (StoP) Project

Purpose: The relationship between whole and refined grain intake and gastric cancer risk has been investigated, but findings remain inconclusive. We aimed to evaluate and quantify the association of whole and refined grain consumption with gastric cancer risk through an individual participant pooled analysis of studies participating in the Stomach cancer Pooling (StoP) Project. Methods: Twenty case-control studies (including 7,943 cases and 19,729 controls) contributed to the analysis of refined grains, and 13 of these (5,658 cases and 15,802 controls) contributed to the analysis of whole grains. Study-specific odds ratios (ORs) were estimated using multivariable logistic regression models and pooled through a two-stage approach based on fixed-effects models. Results: For whole grains, compared with no consumption, the OR was 0.92 (95% confidence interval, CI: 0.84-1.01) for any consumption, and 0.86 (95% CI: 0.77-0.96) for a consumption equal or above the study-specific median. There was an increasing risk of gastric cancer with increasing consumption of refined grains, with an OR for the highest versus the lowest tertile of 1.39 (95% CI: 1.28-1.50) when considering staple grain foods only and 1.52 (95% CI: 1.39-1.65) when also considering grain-based sweets and desserts. Conclusion: Our findings indicate that whole grain consumption is inversely associated, and refined grain consumption directly associated with gastric cancer risk. These findings support current dietary recommendations favoring whole grains over refined grains.