Increased Prevalence of Colorectal Adenomas in Patients with Nonalcoholic Fatty Liver Disease: A Cross-Sectional Study

Background: Nonalcoholic fatty liver disease (NAFLD) is the most common liver disorder worldwide. Previous studies have suggested an association between colorectal adenomas and NAFLD but are limited by a lack of biopsy-proven NAFLD or comparison with matched controls. Objectives: We aimed to determine whether histologically demonstrated NAFLD is an independent risk factor for colorectal adenomas. Methods: Patients who underwent liver biopsy showing steatosis who had also undergone screening or surveillance colonoscopy in 2007-2017 were retrospectively studied by manual chart review, excluding patients with liver disease other than NAFLD. Adenoma detection rates and characteristics such as location, histologic type, and size were compared in the resulting 123 NAFLD patients against controls without liver disease matched by age, gender, and endoscopist. Results: Adenoma prevalence was significantly higher in the NAFLD group at 40.7 versus 28.1% in controls (OR 1.87, 95% CI 1.15-3.03, p = 0.01) and remained significant on multivariable analysis controlling for rates of hyperlipidemia, diabetes, and obesity (OR 1.74, 95% CI 1.05-2.88, p = 0.032). Comparing NAFLD patients with advanced fibrosis to those with simple steatosis, there was a trend toward higher adenoma prevalence in advanced fibrosis (50.0 vs. 36.8%; OR 1.84, 95% CI 0.50-6.70, p = 0.36). Conclusions: Patients with histologically demonstrated NAFLD had a significantly higher adenoma prevalence on colonoscopy compared to matched controls, which remained significant after adjusting for rates of diabetes, obesity, and hyperlipidemia. NAFLD should be investigated further as an independent risk factor for colorectal neoplasia.