The Impact of State Policies for School-Based BMI/Fitness Assessments on Children’s BMI Outcomes and Related Behaviors: An Analysis of Differences by Urbanicity

Childhood obesity continues to be a public health crisis because of its alarming prevalence, especially in rural areas, and its potential for costly long-term health consequences. Schools have been considered natural loci for policies to combat childhood obesity because children spend most of their active hours and consume a substantial share of their calories, at school. Recent policy efforts have involved measuring children’s BMI and/or fitness at schools in order to provide that individual-level information to parents and/or to provide aggregate data to inform districts’ and states’ efforts. Existing empirical evidence on the effects of these policies is mixed, at best. This may be related, in part, to their inability to address residential selection, policy endogeneity, and potential heterogeneity in effects across urbanicity. For example, families may self-select into states with such policies based on their health preferences or states with high obesity rates may be more likely to enact these policies. Moreover, policies might have heterogenous impacts across urban versus rural areas. For example, some research suggests that rural communities have fewer amenities to support healthy lifestyles (e.g. recreational facilities) relative to urban communities, while other research finds that urban schools are more likely to lack the facilities to support physical activity. Our study addresses these limitations by taking advantage of the compulsory assignment of military families across geographic locations to examine whether state BMI/fitness assessment policies influence BMI outcomes and related behaviors among children who attend public schools in rural and urban areas, separately.

Our results suggest that state BMI/fitness assessment policies are protective of unhealthy weight among military children attending rural schools. The state policy was associated with lower odds of overweight and near-overweight (defined as 75th percentile), although not with lower BMI. By contrast, these associations were small and statistically insignificant among children in urban schools. The state policy was also associated with improvements in obesogenic behaviors, particularly among children attending rural schools. Children in rural schools with the state policy demonstrated greater levels of physical activity per week, potentially within the school environment, relative to rural schools without the policy. There was no evidence of these associations among children in urban schools. With respect to food and beverage intake, the state policy was associated with healthier intake among all children, but especially among those attending rural schools. Sensitivity analyses and validity checks provide further support. Our results were robust to stratification of the sample based on the urbanicity of the Army installation’s county versus urbanicity of the school. Further, unadjusted models with only the state policies included as regressors also provided similar findings, as expected given the exogenous assignment induced by the natural experiment. We also explored whether selection played a role by examining parent outcomes, home food environments and neighborhood environments. The results do not appear to be driven by selection of healthier families to particular schools.