BOSTON, Nov. 11, 2016 /PRNewswire/ -- The prevalence of nonalcoholic steatohepatitis (NASH), a progressive type of fatty liver disease, appears to be on the rise in adolescents, increasing four-fold between 1988 and 2010, according to research presented this week at The Liver Meeting® — held by the American Association for the Study of Liver Diseases. NASH is a disease associated with liver damage, which is predominately caused by too much fat in the liver. It often has the same symptoms as alcoholic liver disease, but is not caused by alcohol consumption. Rather, it is part of a group of diseases called nonalcoholic fatty liver disease (NAFLD), which has become the most common cause of chronic liver disease in children and adolescents. While it has been noted the prevalence of NAFLD in children has increased over the past several decades, the prevalence of NASH and advanced fibrosis in children has not been completely explored. Researchers recently aimed to estimate the changes in prevalence of NASH and advanced fibrosis (liver scarring from damage) in children in the United States using two noninvasive prediction scores - the NASH Predictive Index and the Pediatric NAFLD Fibrosis Score. These prediction scores were based on readily available clinical and blood work data to avoid invasive liver biopsies. "It is very clear that NAFLD has become the most common cause of chronic liver disease in children and adolescents with the growing epidemic of obesity in developed countries," says Praveen Kumar Conjeevaram Selvakumar, MD; Pediatric Gastroenterology fellow at Cleveland Clinic, and lead investigator in the study. "NAFLD includes a broad spectrum of liver disease ranging from simple fat accumulation to inflammatory liver damage (NASH) eventually leading to significant liver scarring (fibrosis or cirrhosis). Advanced fibrosis is more common during adulthood. However, NASH can develop at a younger age with 20 percent of NASH patients likely to progress to advanced fibrosis. Data on the prevalence of NASH or advanced fibrosis among children are lacking. This made us look in to the national database to evaluate the trend in the occurrence of NASH or advanced fibrosis among adolescents over a period of years. This research study will help us understand the burden of NAFLD on the U.S. health system, which will further aid us in creating public health efforts to decrease the complications arising from NAFLD." Dr. Selvakumar's team looked at data from adolescents between the ages of 12 and 18 who were enrolled in the National Health and Examination Survey (NHANES) over three different time periods (1988-1994, 1999-2004, and 2005-2010) to estimate trends of suspected NASH and advanced fibrosis. Patients with hepatitis B and/or C, those with enzyme levels (called alanine aminotransferase) greater than 500, those using medications known to potentially cause liver damage (e.g. acetaminophen) and those missing measurements and components needed to assess NASH or advanced fibrosis were excluded from the study.