Preperitoneal fat thickness in childhood obesity: association with serum insulin concentration

The clinical significance of visceral fat accumulation in childhood obesity has remained controversial.

In 35 subjects (18 boys and 17 girls) aged 9-15 years, visceral and subcutaneous fat were estimated by measuring the maximum thickness of preperitoneal fat (Pmax) and the minimum thickness of subcutaneous fat (Smin) in the upper median abdomen, respectively, by ultrasonography. The associations with fasting serum insulin levels converted to logarithm (log(IRI)) were studied for six obesity-related indices, including the obesity index, body fat percentage, waist-to-hip circumference ratio (WHR), Pmax, Smin and the ratio of Pmax to Smin (abdominal wall fat index, AFI).

In girls, the log(IRI) was positively correlated with the Pmax, obesity index, body fat percentage and Smin. In contrast, the log(IRI) was positively correlated only with the Pmax and Smin in boys. There were no significant correlations between the log(IRI) and the WHR or AFI in either sex. The Pmax revealed the highest correlation with the log(IRI) in both boys (r = 0.703, P < 0.001) and girls (r = 0.921, P < 0.0001).

These results indicate the important contribution of visceral fat accumulation to the development of hyperinsulinemia, regardless of sex. Accordingly, it is suggested that evaluating Pmax by ultrasonography may be the most sensitive and reliable method of predicting insulin resistance-associated metabolic derangements in children, compared with other conventional indices of obesity.