Plain language summary
Adolescent obesity is a major public health concern that affects health status not only during adolescence but also during adulthood. The aim of this study was to test whether the HealthCorps program would improve weight status represented by body mass index (BMI; kg/m2) z-score and obesity class. A secondary aim was to identify knowledge and health behaviour domains that would be increased with the program. The study design was a two parallel arm quasi-experimental pre-post comparison design. A total of 2279 students from 62 schools participated in the HealthCorps program. Results indicate that HealthCorps program participation resulted in BMI z-score improvement among overweight/obese female students. Participation also resulted in increased knowledge in most domains regardless of sex and improved a few behaviour domains. However, it did not improve weight status among male students. Authors conclude that the HealthCorps was effective for BMI z-score improvements among female students in addition to significant positive effects on knowledge and a few behaviors in both sexes.
Abstract
BACKGROUND Adolescent obesity is a major public health concern. Open to all high school students regardless of weight status, HealthCorps is a nationwide program offering a comprehensive high school-based participatory educational program to indirectly address obesity. We tested a hypothesis that the HealthCorps program would decrease BMI z-scores among overweight or obese students, and reduce obesity rates, and evaluated its effects on health knowledge and behaviors. METHODS HealthCorps aimed to improve student knowledge and behaviors regarding nutrition quality, physical activity, sleep, breakfast intake, and mental resilience. Participating students received through HealthCorps coordinators weekly or bi-weekly classroom lessons either for a semester or a year in addition to various during- and after-school health-promoting activities and mentorship. Self-reported height and weight were collected along with questionnaires assessing knowledge and behaviors during 2013-2014 academic year among 14 HealthCorps-participating New York City high schools. This quasi experimental two-arm pre-post trial included 611 HealthCorps and 221 comparison arm students for the analytic sample. Sex-specific analyses stratified by weight status were adjusted for age and Hispanic ethnicity with clustering effects of schools and students taken into account. RESULTS HealthCorps female overweight/obese and obese student had a significant decrease in BMI z-scores (post-pre delta BMI z-score = -0.16 (95%CI = (-0.26, -0.05), p = 0.004 for the former; and = -0.23 (-0.44, -0.03), p = 0.028, for the latter) whereas comparison female counterparts did not. The HealthCorps students, but not the comparison students, had a significant increase for all knowledge domains except for the breakfast realm, and reported a greater number of significant behavior changes including fruit and vegetable intake and physical activities. CONCLUSIONS The HealthCorps program was associated with reduced BMI z-score in overweight/obese and obese female adolescents, with enhanced health knowledge and behavior for both sexes. With its wide reach, this may be a promising program to help combat adolescent obesity in schools. TRIAL REGISTRATION This study is registered as a clinical trial at the ClinicalTrials.gov registry with trial number NCT02277496 on September 10, 2014 (Retrospectively registered).
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