The effects of the Child and Adolescent Trial for Cardiovascular Health upon psychosocial determinants of diet and physical activity behavior

Background: The Child and adolescent Trial for Cardiovascular Health is a multisite study of a school-based intervention to reduce or prevent the development of risk factors for cardiovascular disease. The purpose of this paper is to present the evaluation results of the 3-year intervention, focusing upon the psychosocial variables conceptualized as determinants of dietary and physical activity behaviors. Methods: A total of 96 schools across four study sites (California, Louisiana, Minnesota, and Texas) were randomized to two treatment conditions: intervention and control. Pre- and postmeasurements on the health behavior questionnaire were collected from over 6,000 students. The data analyses utilized a nested design approach in which schools served as the primary unit of analysis. Repeated-measures multivariate analyses were applied to investigate effect sizes for each determinant and to explore theoretical relationships among the determinants over time. Results: The findings indicated sustained significant effects in improved knowledge, intentions, self-efficacy, usual behavior, and perceived social reinforcement for healthy food choices (P < 0.0001 for these five variables) after 3 years. Intermittent effects were observed for perceived support and self-efficacy for physical activity. No gender by determinant interaction effects were observed, and girls reported significantly greater perceived reinforcement for healthy eating than did boys. Conclusion: The CATCH program was effective in changing the psychosocial variables likely to influence a reduction in behavior for cardiovascular disease. The study is significant in that it demonstrates the viability and effectiveness of a sustained multifaceted intervention in a preadolescent population. The results point to a need for greater understanding of adolescent developmental issues and the role of community environment (particularly social support) in creating effective curricula.