Effects of 12- and 24-Week Multimodal Interventions on Physical Activity, Nutritional Behaviors, and Body Mass Index and Its Psychological Predictors in Severely Obese Adolescents at Risk for Diabetes

Abstract

Although 7% of US adolescents have impaired fasting glucose, a precursor of type 2 diabetes, research has suggested that few interventions for obese adolescents at risk for diabetes have been effective. Therefore, pediatricians seek effective behavioral treatments for referral for this age group. We wanted to determine the effects of two different durations of nutritional and exercise treatments on changes in nutrition, physical activity, body mass index (BMI), and psychological predictors of BMI change in overweight and obese adolescents at risk for type 2 diabetes. We obtained data from 64 pediatrician-referred patients with diabetes risk factors (mean age, 14.1 years; BMI, ≥99th percentile.) Study participants were assigned to nutrition and exercise treatments for 12 weeks (n = 35) or 24 weeks (n = 29). A specific weight-loss goal was given only for the 24-week group. Both treatments demonstrated significant within-group changes over 12 weeks in days per week of physical activity of at least 60 minutes, physical self-concept, general self, and overall mood. However, they failed to demonstrate significant 12-week increases in fruit and vegetable intake, decreases in sweetened-beverage consumption, or decreases in BMI. Between-group differences were found only in mood changes in favor of the 12-week treatment. In the 24-week treatment, BMI change from week 12 to week 24 was significantly better than corresponding normative data (d = 0.37). Physical self-concept, general self, and mood scores at week 12 explained a significant portion of the variance in BMI change (R2 = 0.13, p = 0.04). Nutrition education alone may be insufficient for nutrition behavior change. Behavioral treatment lasting longer than 12 weeks and having a specific weight-loss goal may be useful for BMI improvements, and attention to participants' self-concept and mood may be important treatment considerations.