BACKGROUND & AIMS: Chronic liver diseases (CLDs) are major causes of morbidity and mortality worldwide. We assessed changes in the prevalence of different types of CLD in the U.S.
METHODS: National Health and Nutrition Examination Surveys (NHANES) conducted between 1988 and 2008 were used to estimate changes in the prevalence and predictors of CLDs. Serologic and clinical data were used to establish the diagnoses of CLDs in 39,500 adults. Statistical analyses were conducted with SUDAAN 10.0.
RESULTS: The prevalence rates for CLD were 11.78% (1988-1994), 15.66% (1999-2004), and 14.78% (2005-2008). During the same period, the prevalence of hepatitis B virus (HBV) infection (0.36%, 0.33%, 0.34%), HCV infection (1.95%, 1.97%, 1.68%), and alcoholic liver disease (1.38%, 2.21%, 2.05%) remained generally stable. In contrast, the prevalence of non-alcoholic fatty liver disease (NAFLD) increased from 5.51% to 9.84% to 11.01%. From 1988 to 1994, NAFLD accounted for 46.8% of CLD cases; from 1994 to 2004 its prevalence increased to 62.84%, and then to 75.1% from 2005 to 2008. During these time periods, steady increases were observed in obesity (21.74%, 30.02%, 33.22%), visceral obesity (35.18%, 48.16%, 51.43%), type II diabetes (5.55%, 7.88%, 9.11%), insulin resistance (23.29%, 32.50%, 35.00%), and hypertension (22.68%, 33.11%, 34.08%). A multivariate analysis showed that during all time periods, obesity was an independent predictor of NAFLD.
CONCLUSIONS: NHANES data collected from 1988 to 2008 show that the prevalence of major causes of CLD remained stable, except for NAFLD, which increased steadily, along with the prevalence of metabolic conditions. Given the increasing rates of obesity, NAFLD prevalence is expected to contribute substantially to the burden of CLD in the US.