School-based obesity-prevention policies and practices and weight-control behaviors among adolescents / Nicole Larson, Cynthia S. Davey, Caitlin E. Caspi, Martha Y. Kubik, Marilyn S. Nanney

Background: The promotion of healthy eating and physical activity within school settings is an important component of population-based strategies to prevent obesity; however, adolescents may be vulnerable to weight-related messages, as rapid development during this life stage often leads to preoccupation with body size and shape. Objective: This study examines secular trends in secondary school curricula topics relevant to the prevention of unhealthy weight-control behaviors; describes cross-sectional associations between weight-related curricula content and students’ use of weight-control behaviors; and assesses whether implementation of school-based obesity-prevention policies/practices is longitudinally related to students’ weight-control behaviors. Design: The Minnesota School Health Profiles and Minnesota Student Survey (grades 9 and 12) data were used along with National Center for Education Statistics data to examine secular trends, cross-sectional associations (n=141 schools), and longitudinal associations (n=42 schools). Main outcome measures: Students self-reported their height and weight along with past-year use of healthy (eg, exercise), unhealthy (eg, fasting), and extreme (eg, use laxatives) weight-control behaviors. Statistical analyses performed: Descriptive statistics, generalized estimating equations, and generalized linear regression models accounting for school-level demographics. Results: There was no observable pattern during the years 2008 to 2014 in the mean number of curricula topics addressing unhealthy weight-control behaviors, despite an increase in the prevalence of curricula addressing acceptance of body-size differences. Including three vs fewer weight-control topics and specifically including the topic of eating disorders in the curricula was related to a lower school-level percent of students using any extreme weight-control behaviors. In contrast, an overall measure of implementing school-based obesity-prevention policies/practices (eg, prohibited advertising) was unrelated to use of unhealthy or extreme behaviors. Conclusions: Results suggest obesity-prevention policies/practices do not have unintended consequences for student weight-control behaviors and support the importance of school-based health education as part of efforts to prevent unhealthy behaviors.

Nutrition.