Obese boys at increased risk for nonalcoholic liver disease: evaluation of 16 390 overweight or obese children and adolescents

Objective: Comorbidities of childhood obesity challenge health-care systems in Europe. Further, there is a lack of population-specific prevalence data and diagnostic strategies available, especially for obesity-related disturbances of liver function. Therefore, the prevalence of elevated liver enzymes and their relationship to biological parameters were studied in a large pediatric obesity cohort. Methods: In 111 specialized pediatric obesity centers in Germany, Austria and Switzerland, 16 390 children and adolescents (age 12.4 +/- 2.6 years, 58% boys) were categorized as overweight (body mass index (BMI)>490th percentile) and obese (>97th percentile) and studied for related comorbidities, especially nonalcoholic fatty liver disease (NAFLD; as defined by aspartate aminotransferase (AST) and/or alanine aminotransferase (ALT) >50Ul(-1)). Data were collected using a standardized software program (APV) for longitudinal multicenter documentation. Pseudonymized data were transmitted for central statistical analysis. Results: In this pediatric cohort, 16% of the study population was overweight, 46% obese and 35% extremely obese (>99.5th percentile extreme obesity (Xob)). NAFLD was present in 11% of the study population, but predominantly in boys (boys vs girls; 14.4: 7.4%; P<0.001), in Xob (obese vs Xob; 9.5: 17.0%; P<0.001) and in older age (<12 vs >= 12 years; 8: 12%; P<0.001; adjusted for BMI). ALT >50Ul(-1) was significantly associated with fasting insulin and BMI-SDS. In multiple logistic regression models, Xob and male gender were strongly associated with NAFLD (odds ratio Xob vs normal weight=3.2; boys vs girls OR=2.3). Conclusion: In a large cohort of overweight and obese European children and adolescents, markers of nonalcoholic liver disease, especially ALT, are frequent and predicted by Xob and male gender. The results underline the epidemiological dimension of this obesity-related morbidity even in childhood. Therefore, at least ALT is recommended as a screening parameter in basic care. International Journal of Obesity (2010) 34, 1468-1474; doi:10.1038/ijo.2010.106; published online 8 June 2010