[Nonalcoholic steatohepatitis in obese children: the prevalence and possible mechanism].

OBJECTIVE: To investigate the prevalence of nonalcoholic steatohepatitis (NASH) in obese children and its possible mechanism.

METHODS: Three subgroups were classified according to their body mass index (BMI) in 123 obese children with BMI over 23 aged 7 to 16:34 cases with BMI> or =31 group; 57 cases with 25< or =BMI<30 group; 32 cases with 23< or =BMI<25 group. Ultrasonographic and biochemical parameters including serum alanine aminotransferase (ALT), serum aspartate aminotransferase (AST), serum cholesterol, serum triglyceride, serum uric acid and free glucose to free insulin ratio (FGIR) were assayed. Twenty four children suspected as benign acanthosis nigricans underwent skin biopsy and its association with nonalcoholic steatohepatitis was also discussed.

RESULTS: Ninety-nine children (80.49 %) showed abnormal hepatic sonograms and 54 were diagnosed as NASH with the prevalence of 43.90%. Compared with the other two groups, BMI> or =31 group was significantly higher in prevalence of abnormal hepatic sonograms, NASH, decreased FGIR and risk of benign acanthosis nigricans (P<0.01). Fifty-four children diagnosed as NASH showed significantly higher incidence of hyperlipidemia, insulin resistance and higher body mass index as compared with 24 subjects without fatty liver changes. In 54 NASH children, 20(37.04%) had benign acanthosis nigricans. By bivariate analysis, ALT and AST were correlated well with BMI, cholesterol, triglyceride and FGIR (r(s)=0.413, 0.290, 0.379, -0.477, P<0.01; r(s)=0.359, 0.349, 0.348, -0.369, P<0.01).

CONCLUSION: There is a high prevalence of nonalcoholic steatohepatitis in simple obese children and high incidence of benign acanthosis nigricans in NASH subjects. BMI> or=30 is a high risk factor of being NASH. Severe disturbance of lipid metabolism and insulin resistance may be involved in the mechanism of NASH.