Objectives: The objective of this study was to evaluate a 12-session home/community-based health promotion/obesity prevention program (Challenge!) on changes in BMI status, body composition, physical activity, and diet.
Methods: A total of 235 black adolescents (aged 11-16 years; 38% overweight/obese) were recruited from low-income urban communities. Baseline measures included weight, height, body composition, physical activity (PA), and diet. PA was measured by 7-day play-equivalent physical activity (> or =1800 activity counts per minute). Participants were randomly assigned to health promotion/obesity prevention that is anchored in social cognitive theory and motivational interviewing and was delivered by college-aged black mentors or to control. Postintervention (11 months) and delayed follow-up (24 months) evaluations were conducted. Longitudinal analyses used multilevel models with random intercepts and generalized estimating equations, controlling for baseline age/gender. Stratified analyses examined baseline BMI category.
Results: Retention was 76% over 2 years; overweight/obese status declined 5% among intervention adolescents and increased 11% among control adolescents. Among overweight/obese youth, the intervention reduced total percentage of body fat and fat mass and increased fat-free mass at delayed follow-up and increased play-equivalent physical activity at postintervention but not at delayed follow-up. Intervention adolescents declined significantly more in snack/dessert consumption than control adolescents at both follow-up evaluations.
Conclusions: At postintervention, there were intervention effects on diet and PA but not BMI category or body composition. At delayed follow-up, dietary changes were sustained and the intervention prevented an increase in BMI category. Body composition was improved for overweight/obese youth. Changes in body composition follow changes in diet and PA and may not be detected immediately after intervention.
Trial registration: ClinicalTrials.gov NCT00746083.