Gastric and colorectal cancer incidence attributable to dietary factors in Korea.

Background: Dietary factors play a role in the etiology of gastrointestinal cancer. We aimed to estimate the burden of gastric and colorectal cancer that can be attributable to dietary factors in adults aged 20 years and older in Korea in 2018. Methods: Dietary intakes in 2000 were estimated using data from the 2001, 2005, and 2007-2018 Korea National Health and Nutrition Examination Survey (KNHANES). For counterfactual scenarios, the optimal level of intake suggested by the Global Burden of Disease (GBD) study was used if it was available. Otherwise, the average intake values of reference groups among published studies globally were used. Relative risks (RRs) were pooled through dose-response meta-analyses of Korean studies. Results: In Korea in 2018, an estimated 18.6% of gastric cancer cases and 34.9% of colorectal cancer cases were attributed to the combined effect of evaluated dietary factors. High intake of salted vegetables accounted for 16.0% of gastric cancer cases, followed by salted fish at 2.4%. Low intakes of whole grains (16.6%) and milk (13.7%) were leading contributors to colorectal cancer cases, followed by high intakes of processed meat (3.1%) and red meat (5.9%), and a low intake of dietary fiber (0.5%). Conclusions: These results suggest that a considerable proportion of gastric and colorectal cancer incidence might be preventable by healthy dietary habits in Korea. However, further research is needed to confirm the associations between dietary factors and gastric and colorectal cancers in Korea and to formulate and apply effective cancer prevention strategies to Koreans.