Changes in serum interleukin-6 concentrations in obese children and adolescents during a weight reduction program

OBJECTIVE: To investigate the effect of short term energy restriction combined with physical activity on serum concentrations of Interleukin-6 (IL-6) in obese children and adolescents. DESIGN: Longitudinal intervention study of 3.8-5 MJ daily with exercise. SUBJECTS: Forty-nine white obese children and adolescents (31 girls, age 11.9 1.8 y; 18 boys, age 11.6 +/- 1.7 y). MEASUREMENTS: Indexes of obesity IL-6, leptin, estradiol, systolic and diastolic blood pressure; heart rate at baseline and after 3 weeks. RESULTS: All determined parameters decreased significiantly during the 3 week program (IL-6: 3.9 +/- 4.7 vs 2.0 +/- 2.2 pg/ml; P < 0.05). Body mass index (BMI) fat mass, percentage fat mass (indexes of obesity), and leptin were not related to IL-6 before the program. In contrast, IL-6 concentrations correlated significantly with indexes of obesity and leptin after weight loss. IL-6 concentrations did not correlate with estradiol, systolic and diastolic blood pressure, and heart rate. Changes in IL-6 concentrations correlated significantly with changes in BMI (r = 0.25, P < 0.05). CONCLUSION: An improved body composition induced by restriction of energy intake and increase in physical activity is associated with more favorable serum concentrations of IL-6 in obese children and adolescents.