Liver involvement in obese children. Ultrasonography and liver enzyme levels at diagnosis and during follow-up in an Italian population.

Our aim was to evaluate incidence and risk factors of liver involvement in obese Italian children as assessed by both ultrasonographic and biochemical parameters. In seventy-five consecutive obese children (age 9.5 +/- 2.9 years, males/females 41/34), serum levels of enzymes and ultrasonography of the liver were evaluated. Tests were repeated one, three, and six months after starting a moderate hypocaloric diet and an exercise program. Three obese children who were found to have chronic viral hepatitis were excluded from the study. Thirty-eight of 72 (53%) obese children had an ultrasonographic image of bright liver consistent with liver steatosis. The latter was severe in nine children, moderate in 16, and mild in 13. Eighteen obese children (25%) had elevated transaminase levels. Bright liver and hypertransaminasemia were not due to any of the most common causes of liver disease. Both were rapidly responsive to loss of weight, confirming that liver involvement was secondary to obesity and that steatosis or steatohepatitis rather than fibrosis were involved. Obesity duration not more than three years (odds ratio = 4.77), a higher degree of obesity (odds ratio = 2.09), and hypertransaminasemia (odds ratio = 2.15) appeared as important predictive factors of liver involvement at ultrasonography. Incidence of liver involvement assessed by means of ultrasonography is significantly higher than that revealed by measurement of serum liver enzymes. A short duration of obesity emerged as a potentially new risk factor of liver involvement in the pediatric obese population and needs to be confirmed in future studies.