To assess recent trends in nonalcoholic fatty liver disease (NAFLD) prevalence among US adolescents.

Cross-sectional data from 12 714 12-19 year olds (exclusions: chronic hepatitis, hepatotoxic medications) in the National Health and Examination Survey between 1988-1994 and 2007-2010 were used to estimate trends in suspected NAFLD, defined as overweight (body mass index ≥85th percentile) plus elevated alanine aminotransferase levels (boys >25.8 U/L; girls >22.1 U/L). Linear trends in prevalence and the independent effect of demographic indicators and adiposity on NAFLD risk were tested using regression models. Complex sampling methods and P values of <.05 were used to assess statistical significance.

Suspected NAFLD prevalence (SE) rose from 3.9% (0.5) in 1988-1994 to 10.7% (0.9) in 2007-2010 (P < .0001), with increases among all race/ethnic subgroups, males and females, and those obese (P trend ≤.0006 for all). Among those obese, the multivariate adjusted odds of suspected NAFLD were higher with increased age, body mass index, Mexican American race, and male sex; the adjusted odds in 2007-2010 were 2.0 times those in 1988-1994. In 2007-2010, 48.1% (3.7) of all obese males and 56.0% (3.5) of obese Mexican American males had suspected NAFLD.

Prevalence of suspected NAFLD has more than doubled over the past 20 years and currently affects nearly 11% of adolescents and one-half of obese males. The rapid increase among those obese, independent of body mass index, suggests that other modifiable risk factors have influenced this trend.