Objective: To examine the link between childhood overweight status and elementary school outcomes.
Design: Prospective study design: multivariate regression models examining the association between changes in overweight status and school outcomes between kindergarten entry and end of third grade, after controlling for various child, family and school characteristics.
Subjects: Nationally representative sample of US children who entered kindergarten in 1998, with longitudinal data on body mass index (BMI) and school outcomes at kindergarten entry and end of third grade.
Measurements: Wide range of elementary school outcomes collected in each wave including academic achievement (math and reading standardized test scores); teacher reported internalizing and externalizing behavior problems (BP), social skills (self-control, interpersonal skills) and approaches to learning; school absences; and grade repetition. Measurements of height and weight in each wave were used to compute BMI and indicators of overweight status based on CDC growth charts. A rich set of control variables capturing child, family, and school characteristics.
Results: Moving from not-overweight to overweight between kindergarten entry and end of third grade was significantly associated (P<0.05) with reductions in test scores, and teacher ratings of social-behavioral outcomes and approaches to learning among girls. However, this link was mostly absent among boys, with two exceptions - boys who became overweight had significantly fewer externalizing BPs (P<0.05), but more absences from school compared to boys who remained normal weight. Being always-overweight was associated with more internalizing BP among girls but fewer externalizing BPs among boys.
Conclusion: Change in overweight status during the first 4 years in school is a significant risk factor for adverse school outcomes among girls but not boys. Girls who become overweight during the early school years and those who start school being overweight and remain that way may need to be monitored carefully.