Clinical Features of Pediatric Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is a metabolic disorder characterized by excessive fat accumulation in the liver not associated with infection, medication, or an autoimmune process. The majority of individuals with NAFLD are asymptomatic and are found to have elevated hepatic transaminases on blood work that has been drawn for screening purposes or as part of an entirely different evaluation. NAFLD is a spectrum of disease ranging from relatively benign nonalcoholic fatty liver (NAFL) to an inflammatory process affecting the hepatocytes called nonalcoholic steatohepatitis (NASH) that can ultimately lead to fibrosis, cirrhosis, and increased risk of hepatocellular carcinoma.1–3 Currently, the only way to differentiate between NAFL and NASH is by determining the histopathology on liver biopsy. NAFLD is a common condition, affecting approximately 20% of Americans overall,4,5 and an estimated 3% to 17% of children.6,7 An obesity-associated condition, nearly 75% of overweight/obese adults5 and 38% of overweight/obese children have NAFLD.6 The prevalence of NASH is also rising as it affects approximately 1.1% to 14% of Americans,8,9 including 19% of individuals who are obese, and 50% of individuals who are morbidly obese.10 These numbers may ultimately lead to a rise in progressive liver scarring or NAFLD-associated cirrhosis and hepatocellular carcinoma.11 In addition to adiposity, NAFLD is associated with the metabolic syndrome (MetS), a cluster of risk factors associated with cardiovascular disease and “type 2” diabetes mellitus (T2DM).6,7,12 NAFLD’s associations with cardiovascular disease, type 2 diabetes mellitus, cirrhosis, and hepatocellular carcinoma make NAFLD a serious public health concern. In this review, we will discuss emerging data regarding etiology and clinical features of NAFLD in childhood, particularly as they relate to the need for screening among children with obesity and increased metabolic risk.