Hepatic steatosis in a school population of overweight and obese adolescents

Objective: To assess hepatic steatosis by ultrasound method as a concomitant risk factor among overweight adolescents. Methods: A case-control study including 83 cases (47 overweight and 36 obese) and 89 controls (normal weight), frequency matched by gender, year of birth, pubertal stage (Tanner 4/5), and income. Cases and controls were selected from 1,420 students enrolled in a Vila Mariana public high school, in Sao Paulo, Brazil. Must et al. criteria were used for nutritional status classification. Nonalcoholic fatty liver disease was diagnosed through hepatic ultrasonography performed and analyzed by one radiologist. Hepatic enzymatic activities (alanine and aspartate transaminases, alkaline phosphatase, gamma-glutamyl transpeptidase) and direct bilirubin were measured. Eight covariables were fitted into logistic regression models; criterion for inclusion of variables was the association with overweight in the bivariate analyses (p < 0.20). A value of p < 0.05 was set as the criterion for inclusion into the final logistic regression models. Results: Prevalence of hepatic steatosis diagnosed through ultrasonography was 27.7% in overweight/obese students and 3.4% in normal weight students. Adjusted odds ratios (95%CI) for images compatible with nonalcoholic fatty liver disease and gamma-glutamyl transpeptidase > 24 U/L were 10.77 (2.45-47.22) and 4.18 (1.46-11.94), respectively. Conclusions: This is the first population-based study showing that hepatic steatosis is strongly associated with overweight/obesity among adolescents attending a Brazilian public school. The diagnostic tool used in this investigation is a non-invasive method that might be applied to monitor overweight and obese adolescents and to propose actions for preventing more severe hepatic diseases in adulthood.