Components of the metabolic syndrome are negative predictors of weight loss in obese children with lifestyle intervention.

BACKGROUND AND AIMS: Insulin resistance has been proposed to be associated with weight gain in obesity. Therefore, we analyzed the impact of insulin resistance and its associated cardiovascular risk factors (CRFs) summarized in the Metabolic Syndrome (MetS) on change of weight status in obese children.

METHODS: We analyzed 484 obese children who had participated in a lifestyle intervention and 533 obese children without lifestyle intervention. The changes of BMI-SDS in the time period of 1-year were related to baseline fasting insulin resistance index HOMA, blood pressure, waist circumference, waist-to-height ratio, lipids, uric acid, and HbA1c.

RESULTS: In contrast to obese children without lifestyle intervention, BMI-SDS decreased and the majority of CRFs improved significantly in obese children with lifestyle intervention. Age, BMI, waist circumference, waist-to-height ratio, blood pressure, uric acid, triglycerides, and HOMA were negatively significantly related to reduction of BMI-SDS in children with lifestyle intervention. In multiple linear regression analysis adjusted for gender, pubertal stage, and treatment center (R² = 0.26), waist circumference (r = -0.016 [confidence interval -0.019 up to -0.013], p < 0.001) was the strongest negative predictor of weight loss in children with lifestyle intervention. In children without lifestyle intervention, we did not find significant relationships between change of BMI-SDS and CRFs including insulin resistance in multiple regression analysis.

CONCLUSIONS: Insulin resistance and components of the MetS were associated negatively with weight loss in lifestyle intervention. Waist circumference at baseline was the strongest negative predictor of weight loss suggesting that obese children with abdominal fat distribution need more intensive interventions. This study is registered at clinicaltrials.gov (NCT00435734).