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.
The researchers defined NAFLD as a BMI percentile greater than 85, coupled with elevated enzymes. NASH was defined as a presence of NAFLD and a score on the NASH predictive index greater than 75. Finally, advanced fibrosis was defined as a presence of NAFLD and a Pediatric NAFLD Fibrosis Score greater than eight.
Dr. Selvakumar's team looked at a total of 8,539 NHANES participants and noticed a significant increase in the prevalence of both NAFLD and NASH from 3.3 percent and .74 percent from 1988 to 1994 to 8.8 percent and 3.1 percent from 1999 to 2004, and 10.1 percent and 3.4 percent from 2005 to 2010, respectively.
The researchers observed the increasing trend of NASH among children in the U.S. across all ethnic groups as well as males and females. In the 2005 to 2010 period, the prevalence of NASH was highest among Mexican-American children (15.4 percent) Looking at the data through another analysis revealed older age, male gender, Mexican-American ethnicity, BMI percentile and study time period were all associated with higher odds of having NASH.
Finally, the researchers noted low prevalence of advanced fibrosis across those studied (.20 percent in the later time periods); however, the disease remained more prevalent among Mexican-American children (at 1.4 percent).
"It is very evident from our data analysis that there has been a steady and about four-fold increase in the occurrence of NASH among the adolescents during the last two decades," Dr. Selvakumar says. "The prevalence of advanced fibrosis in adolescents still remains low, but we found higher prevalence among Mexican-American adolescents. The reason for this higher prevalence of advanced fibrosis among Mexican-American adolescents is not clear, but it possible that genetic predisposition might play a role. Therefore, it is very essential that both the public and physicians are aware of the increasing public health burden of NAFLD. Needless to say, it is important to diagnose NAFLD earlier and take necessary steps, such as healthy diet habits and weight loss, to prevent the disease progression – especially among high-risk populations, such as Mexican-Americans."
Dr. Selvakumar will present these findings at AASLD's press conference in Room 313 at John B. Hynes Veterans Memorial Convention Center in Boston on Saturday, November 12 at 4pm. Dr. Sevakumar will present the study entitled "Prevalence of nonalcoholic steatohepatitis and advanced fibrosis in adolescents with nonalcoholic fatty liver disease in the United States" on Monday, November 14 at 3:45pm in Ballroom A. The corresponding abstract (number 202) can be found in the journal, Hepatology – Special Issue: The 67th Annual Meeting of the American Association for the Study of Liver Diseases: The Liver Meeting 2016.
About the AASLD
AASLD is a medical subspecialty society representing clinicians and researchers in liver disease. The work of our members has laid the foundation for the development of drugs used to treat patients with viral hepatitis. Access to care and support of liver disease research are at the center of AASLD's advocacy efforts.
AASLD is the leading organization of scientists and healthcare professionals committed to preventing and curing liver disease. AASLD was founded in 1950 by a small group of leading liver specialists and has grown to an international society responsible for all aspects of hepatology.
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SOURCE American Association for the Study of Liver Diseases (AASLD)