A recent study shows that the prevalence of nonalcoholic fatty liver disease (NAFLD) in adolescents has increased over a 20 year period in the U.S. (J Pediatr 2013; 162: 496-500).

Using a cross-sectional data from 12,714 adolescents, aged 12-19, from the National Health and Examination survey, the prevalence of suspected NAFLD has more than doubled over the past 20 years and currently affects nearly 11% of adolescents.  Approximately one-half (48%) of obese males have NAFLD.

Suspected NAFLD was defined as elevated ALT in an overweight or obese child.  Specific ALT values were chosen using sex-specific cut points (>25.8 U/L for boys and >22.1 for girls).

• Besides increased NAFLD, the prevalence of obese BMI (≥95%) and severe obesity (BMI ≥99%) also increased steadily.  Between 1988-1994, obese BMI accounted for 11.2% and severe obese BMI 1.5%.  By 2007-2010, these increased to 20.% and 5.5% respectively.
• For suspected NAFLD, in 1988-94 compared to 2007-2010, the prevalence went from 3.9% to 10.7%.

Probably the biggest limitation of this study was considering “suspected NAFLD” only in overweight or obese children.  The authors chose to do this to increase the specificity of their diagnosis and avoid overestimating the prevalence of NAFLD.

Related blog posts:

NAFLD Guidelines 2012 | gutsandgrowth

Pediatric NAFLD histology score | gutsandgrowth