With a remarkable increase in the prevalence of childhood obesity, the prevalence of nonalcoholic fatty liver disease is assumed to be increasing. The aim of this study is to evaluate the prevalence of nonalcoholic fatty liver disease, hyperlipidemia, and glucose intolerance in normal and obese children.

A total of 2,206 elementary students (boys: 1340, girls: 866) were grouped according to obesity index; normal group and obesity group (mild, moderate, severe). Aspartate aminotransferase (AST, SGOT) and alanine aminotransferase (ALT, SGPT) were measured with total cholesterol, triglyceride, and fasting blood glucose.

Compared with the 4.6% of elevated aminotransferases in normal group, obese groups showed significantly higher prevalence; 12.1% in mild obesity group, 19.4% in moderate group, and 21.6% in severe group (p<0.0001). The prevalence of hypertriglyceremia was 16.9% in normal weight group, which was significantly lower than obesity group (mild obesity group 30.3%, moderate and severe 37.6%, 38.2% each). In boys, the prevalences of elevated aminotransferases in normal weight and obese groups (mild, moderate, severe) were 6.8%, 18.0%, 23.0%, and 26.0%, respectively (p<0.0001). In girls, those were 2.1%, 5.1%, 12.0%, and 12.6%, respectively (p<0.0001). The prevalence of hypertriglyceremia was relative to severity of obesity in boys and girls (p<0.0001).

The prevalence of elevated serum liver enzymes increased with severity of obesity. For the prevention and treatment of fatty liver and hypertriglycemia, it is important to lower the obesity degree and enforce the education for a weight loss in the student and the parents.