[Plasma levels of adiponectin and tumor necrosis factor-alpha in children with obesity].

OBJECTIVE: To examine plasma adiponectin (ADPN) and tumor necrosis factor-alpha (TNF-alpha) levels and their correlation in children with obesity in order to investigate the roles of both in the development of childhood obesity.

METHODS: One hundred and forty-seven children with obesity and 118 normal children who were randomly sampled from five primary schools from the Kaifu District in Changsha were enrolled. Physical shape indexes, including height, weight, waist circumference, hip circumference, and waist to hip ratio (WHR) were measured. Body mass index (BMI) was calculated. Blood pressure was measured. Percentage of body fat (%BF) was measured with dual energy X-ray absorptiometry. Plasmal levels of ADPN and TNF-alpha were detected using ABC-ELISA. Blood concentrations of triglycerides (TG), total cholesterol (TC), high density lipoprotein-cholesterol (HDL-C) and low density lipoprotein-cholesterol (LDL-C) were measured by automatic biochemistry analyzer. Fasting blood glucose level was measured by glucose oxidase method. Fasting blood insulin level was assayed by radioimmunity. Homeostasis model assessment for insulin resistance (HOMA-IR) was performed.

RESULTS: Plasma ADPN levels in obese children significantly decreased compared with those in normal children (8.12+/-2.54 mg/L vs 12.22+/-4.68 mg/L; p<0.05), and had a negative correlation with plasma TNF-alpha levels, BMI, WHR and HOMA-IR (p<0.01), and with %BF, fasting insulin, systolic blood pressure and TG (p<0.05). Plasma TNF-alpha levels in obese children significantly increased compared to normal children (171.38+/-34.33 ng/L vs 91.07+/-21.60 ng/L; p<0.01) and positively correlated with BMI, WHR, %BF, fasting insulin, HOMA-IR, TG and systolic blood pressure (p<0.01), and negatively with HDL (p<0.05). Multiple stepwise regression analysis showed that ADPN, BMI and TNF-alpha were main influential factors for %BF (R2=0.926, p<0.01). There was a significant interaction between ADPN and TNF-alpha (p<0.05).

CONCLUSIONS: Plasma ADPN levels decreased and plasma TNF-alpha levels increased in children with obesity and both were main influential factors for %BF in children. There was an interaction between ADPN and TNF-alpha, suggesting that they both participate in the development of childhood obesity.