Abstract
We investigated the association between nonalcoholic fatty liver disease (NAFLD) and gastrointestinal tract cancer in the general population. Retrospective data on individuals aged ≥20 years who received healthcare checkups from January 1, 2009 to December 31, 2009 were analyzed using the National Health Insurance Database in Korea. NAFLD was defined based on the fatty liver index (FLI ≥60). The primary outcome was newly diagnosed esophageal, stomach, or colorectal cancer using ICD-10 codes during follow-up until 31 December 2017. Cox regression analysis was used to estimate hazard ratios (HRs) and 95% confidence intervals (95% CIs). Among 8,120,674 subjects, 936,159 adults (11.5%) were identified as having NAFLD. Their mean age was 46.7 ± 14.1 years, and 52.1% were male. During the follow-up period (7.2 years), 3,792 esophageal, 57,292 stomach and 68,769 colorectal cancer cases were identified. FLI ≥60 was significantly associated with the development of esophageal (HR 2.10, 95% CI 1.88-2.35), stomach (HR 1.18, 95% CI 1.14-1.22), and colon cancer (HR, 1.23, 95% CI 1.19-1.26) after multivariable adjustment. Compared to subjects without NAFLD, all-cause mortality in patients with esophageal (HR 1.46, 95% CI 1.28-1.67), stomach (HR 1.26, 95% CI 1.18-1.34), and colorectal cancer (HR 1.16, 95% CI 1.10-1.22) was significantly increased in subjects with NAFLD (FLI ≥60). NAFLD defined using FLI was a good predictive indicator for GI tract malignancy and all-cause mortality in the general population. Subjects with NAFLD are needed for active surveillance of esophageal, stomach, and colorectal cancers.