Serum leptin, insulin resistance and soft tissue composition by dual energy X-ray absorptiometry in obese children

ABSTRACT

This work aimed to study serum leptin and insulin resistance in obese children and their relation to body composition by DEXA and various measurements of obesity. Thirty-three obese subjects body mass index [BMI] > 95th centile, were enrolled in this study [12 males and 21 females]. Their age ranged from 4 years to 15 years [mean 9.4 +/- 2.93]. Sixteen healthy age- and sex- matched Egyptian children were taken as controls. Obese children and the control group were subjected to thorough anthropometric measurements, estimation of BMI and weight% to ideal weight for height, DEXA study for body composition, serum Ieptin by ELISA and serum insulin [ELISA], blood glucose fasting and postprandial to assess insulin resistance. Insulin resistance index. IRP=Fasting Glucose x Fasting Insulin / 22.5. The study showed that obese children had significantly higher BMI and weight% to ideal weight for height compared to controls. Percent total body fat by DEXA was significantly higher in obese children compared to the controls [49.47 +/- 6.12 vs 19.85 +/- 5.06] [P< 0.0001] and arm fat percent in obese children was 52.92 +/- 8.46 vs. 16.84 +/- 4.6 in controls [P< 0.0001]. Also significantly higher trunk fat/lower limb fat by DE][A was detected [1.21 +/- 0.2 vs 0.81 +/- 0.07, P<0.0001]. IRI in obese children was 68.5 +/- 26.8 vs 19.74 +/- 4.8 in controls [P<0.0001] and serum leptin was higher in obese compared to nonobese children [40.71 +/- 22.73 vs. 10.38 +/- 16.08, P<0.001]. Serum leptin and IRI showed a significant correlation with BMI, weight% to ideal weight for height,% total body fat by DEXA and% arm fat. Moreover, a significant correlation was obtained between IRI and serum leptin [P<0.001]. Obesity is associated with insulin resistance and high serum leptin level, which denote serum leptin resistance. Both are correlated with BMI, weight% to ideal weight for height,% total body fat by DEXA and% arm fat by DEXA