Associations between the home and school environments and child body mass index.

This paper examined associations between various aspects of home and school environments and child body mass index (BMI) in the Early Childhood Longitudinal Study - Kindergarten cohort, a panel dataset of US children collected from 1998 to 2004. Using three-level growth curve modeling with a sample of approximately 11,400 children, it assessed whether these aspects were related to initial BMI and to the rate of growth of BMI over the period from kindergarten to fifth grade, independent of a large number of controls. A number of home and school factors were associated with initial BMI and the growth of BMI. Greater hours of sleep by children, more lunches eaten at school, and the adequacy of their school cafeterias and the adequacy of their school gymnasiums were all significantly associated with lower initial levels of BMI. More breakfasts typically eaten per week with their families and greater minutes of recess (free time for activity at school) were each associated with decreases in the rate of BMI growth over time, while more television watched, greater average hours of weekly maternal employment, more school lunches and school breakfasts eaten, and the adequacy of children's gymnasiums were associated with faster rates of BMI growth over the study period. The study adds to the existing literature on environmental influences on child BMI by illustrating the utility and necessity of examining multiple influences within a single analytic framework. Further research and policy efforts should continue to acknowledge the multi-etiological manner by which the environment can affect rates of child obesity.