Trends in the Burden of Nonalcoholic Fatty Liver Disease in a United States Cohort of Veterans

Background & Aims: Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease in the United States. However, few data are available on recent trends in the incidence and prevalence of NAFLD in the U.S. Methods: We analyzed the national Veterans Administration databases from 2003 to 2011 and calculated the age-adjusted prevalence and incidence of NAFLD for the overall sample of patients and by demographic subgroups. We used a previously validated algorithm to define NAFLD, which was based on persistent increases in levels of liver enzymes in the absence of positive results from tests for hepatitis C or hepatitis B or evidence of excessive alcohol use. Results: Of the 9,784,541 patients with at least 1 visit to the Veterans Administration between 2003 and 2011, 1,330,600 patients (13.6%) had NAFLD. The annual incidence rates of NAFLD remained stable (from 2.2% to 3.2%) during the study duration. The prevalence of NAFLD increased from 6.3% in 2003 (95% confidence interval, 6.26%-6.3%) to 17.6% in 2011 (95% confidence interval, 17.58%-17.65%), a 2.8-fold increase. The incidence and prevalence increased at significantly greater rates in patients younger than 45 years vs older patients. Conclusions: In a U.S. population, the annual incidence of NAFLD ranges from 2% to 3%. The prevalence of NAFLD more than doubled from 2003 through 2011; it is likely to continue to increase because of a steady overall incidence coupled with a rising incidence in younger individuals.