Relationship Between Nonalcoholic Fatty Liver Disease and Low Skeletal Muscle Mass in Obese Youth

Previous studies in adults have found a correlation between nonalcoholic fatty liver disease (NAFLD) and sarcopenia. The present study evaluated the relationship between NFALD and skeletal muscle mass in overweight/obese youth. A total of 234 children and adolescents (age 8-16) was stratified into tertiles based on relative muscle mass (RMM). Total, regional lean body mass, and total fat mass were obtained by dual-energy X-ray absorptiometry. RMM was defined as the percent of muscle mass (kg) relative to the sum of muscle and fat mass (kg). NAFLD was diagnosed via ultrasononography and a subset of participants with NAFLD (n=40) underwent a liver biopsy. The lowest tertile had a significantly higher risk for obesity, dyslipidemia, insulin resistance, metabolic syndrome, NAFLD, and nonalcoholic steatohepatitis (NASH). The present study demonstrated an association between low muscle mass, NAFLD, and NASH in overweight/obese youth. Despite the strong scientific merits of the present study, a lack of race/ethnic description could be a major critique as different ethnic background (specifically in the minorities) may be disproportionately impacted by fat distribution and relative muscle mass. Even though there is a clear relationship between sarcopenia and NAFLD in the elderly, this association may not stem from the same origin in the pediatric population. Lastly, but not least, future studies should evaluate NAFLD in obese youth with varying degrees of metabolic disorders (i.e., metabolic syndrome).