The academic penalty for gaining weight: a longitudinal, change-in-change analysis of BMI and perceived academic ability in middle school students

• Published in: International Journal of Obesity 2015-09, Vol.39 (9), p.1408-1413
• Main Authors: Kenney, E L, Gortmaker, S L, Davison, K K, Bryn Austin, S
• Format: Article
• Language: English
• Subjects: 692/499; 692/698; 692/699/1702/393; 692/700/139/2818; 692/700/1720/3187; Academic ability; Academic achievement; Analysis; Behavioral sciences; Bias; Body Mass Index; Body size; Body weight; Child; Child Development; Child, Preschool; Childhood obesity; Children; Children & youth; Confidence intervals; Correlation analysis; Educational Status; Epidemiology; Faculty; Female; Girls; Health aspects; Health Promotion and Disease Prevention; Humans; Intelligence; Internal Medicine; Kindergarten; Language; Longitudinal Studies; Male; Medicine; Medicine & Public Health; Metabolic Diseases; Middle and junior high school students; Middle school students; Middle schools; Obesity; original-article; Overweight; Overweight - epidemiology; Overweight - psychology; Perceptions; Predictive Value of Tests; Prognosis; Public Health; Ratings; Ratings & rankings; Reading; Regression analysis; Regression models; Schools; Social Perception; Standard scores; Standardized tests; Statistical analysis; Students - statistics & numerical data; Teachers; Teenagers; United States - epidemiology; Weight Gain
• ISSN: 0307-0565; 1476-5497
• DOI: 10.1038/ijo.2015.88

Background/Objectives: Worse educational outcomes for obese children regardless of academic ability may begin early in the life course. This study tested whether an increase in children’s relative weight predicted lower teacher- and child-perceived academic ability even after adjusting for standardized test scores. Subjects/Methods: Three thousand three hundred and sixty-two children participating in the Early Childhood Longitudinal Study–Kindergarten Cohort were studied longitudinally from fifth to eighth grade. Heights, weights, standardized test scores in maths and reading, and teacher and self-ratings of ability in maths and reading were measured at each wave. Longitudinal, within-child linear regression models estimated the impact of a change in body mass index (BMI) z -score on change in normalized teacher and student ratings of ability in reading and maths, adjusting for test score. Results: A change in BMI z -score from fifth to eighth grade was not independently associated with a change in standardized test scores. However, adjusting for standardized test scores, an increasing BMI z -score was associated with significant reductions in teacher’s perceptions of girls’ ability in reading (−0.12, 95% confidence interval (CI): −0.23, −0.03, P =0.03) and boys’ ability in math (−0.30, 95% CI: −0.43, −0.17, P