Abstract
IMPACT (Ideas Moving Parents and Adolescents to Change Together) is a 3-group randomized, multi-level trial comparing the efficacy of two distinct behavioral interventions and a control condition on body mass index (BMI) in middle school urban youth who are overweight/obese. Interventions include: (1) SystemCHANGE (SC), a promising new behavior change approach that focuses on system redesign of the family environment and daily routines; (2) HealthyCHANGE (HC), a cognitive-behavioral and Motivational Interviewing (MI)-consistent approach to behavior change that focuses on increasing intrinsic motivation, self-monitoring, goal setting, and problem solving; and (3) diet and physical education counseling (attention control). In addition, about half of the participants are enrolled in a K-8 public school that offers an innovative community-sponsored fitness program, augmented by study-supported navigators. In addition to the primary interventions effects, the study assesses the moderating effect of the school environment on BMI, blood pressure, cardiovascular risk factors, and quality of life. The sample consists of 360 children entering 6th grade from a large urban school district in the Midwest, identified through an existing BMI screening program. The intervention period is 36 months, and measures are obtained at baseline, 12, 24, and 36 months. Using intent-to-treat analyses across the 36-month intervention window, we hypothesize that both SC and HC will have a greater impact on BMI and other health outcomes compared to health education alone, and that the enriched school environment will enhance these effects. This manuscript describes IMPACT's study design and methods.