Insulin resistance status: predicting weight response in overweight children.

OBJECTIVE To assess the relationship between insulin resistance and body mass index (BMI) z score associated with dietary modification that focuses on limiting sweetened beverage consumption in overweight children. DESIGN A retrospective cohort study conducted between July 1, 2004, and April 28, 2006. SETTING Community-based primary care practices treating children. PATIENTS Forty-five children (aged < or =18 years) at or above the 95th percentile of BMI for age and sex. Intervention Children and parents were instructed by a dietitian regarding caloric reduction and modification of sweetened beverage intake. MAIN OUTCOME MEASURES Insulin resistance at baseline was calculated from fasting insulin and glucose levels (ie, homeostatic model assessment [HOMA]) and change in BMI z score from baseline to 12-week follow-up. RESULTS Change in BMI z score in response to a decrease in sweetened beverages correlated (Pearson product moment correlation coefficient = 0.42; P < .01) with baseline insulin resistance. Those with a decrease in or an unchanged BMI z score had significantly greater insulin resistance than those whose BMI z score increased (mean [SD] HOMA, 6.2 [4.2] vs 2.6 [2.0], P < .01). Linear regression confirmed that HOMA was a significant predictor of change in BMI z score when controlling for age, race, and sex. CONCLUSIONS Among overweight children in primary care practices, a significant relationship was found between insulin resistance and the change in BMI z score associated with a dietitian-mediated intervention that includes a focus on decreasing sweetened beverage consumption. Estimating insulin resistance may inform dietary recommendations for overweight children.