Nonalcoholic fatty liver disease in adolescents and young adults: The next frontier in the epidemic.

Nonalcoholic fatty liver disease (NAFLD) is a significant health burden in adolescents and young adults (AYAs) which has substantially risen in prevalence over the last decades. The occurrence of NAFLD parallels high rates of obesity and metabolic syndrome in this age group, with unhealthy lifestyle also playing an independent role. Genetic factors, sex, and ethnicity should be considered in a risk stratification model. NAFLD and nonalcoholic steatohepatitis (NASH) in AYAs often go unrecognized and, if untreated, can progress eventually to cirrhosis requiring liver transplantation (LT) before the age of 40. Recently, NASH has increased as an indication for LT in this age group. Important knowledge gaps include the feasibility of noninvasive diagnostic tests and imaging modalities as well as uncertainty about unique histological features and their predictive value. Future clinical trials focused on AYAs are needed to determine effectiveness of therapies. Tools for increasing awareness and prevention of NAFLD in AYAs are greatly needed. (Hepatology 2017;65:2100-2109).