Obesity impairs academic attainment in adolescence: findings from ALSPAC, a UK cohort.

J N Booth,J M E Boyle,C Joinson,J J Reilly,P D Tomporowski,A R Ness,S D Leary

doi:10.1038/ijo.2014.40

Abstract

Objective:While being overweight or obese in adolescence may have detrimental effects on academic attainment, the evidence base is limited by reliance on cross-sectional studies with small sample sizes, failure to take account of confounders and lack of consideration of potential mediators. The present study aimed to address these limitations and examine longitudinal associations between obesity in adolescence and academic attainment.Design:Associations between weight status at 11 years old and academic attainment assessed by national tests at 11, 13 and 16 years were examined in the Avon Longitudinal Study of Parents and Children. Healthy weight was defined as body mass index (BMI) Z-score <1.04; overweight as BMI Z-score 1.04–1.63; obesity as BMI Z-score ⩾1.64.Participants:Data from 5966 participants with objectively measured weight status were examined: 71.4% were healthy weight (1935 males; 2325 females), 13.3% overweight (372 males; 420 females) and 15.3% obese (448 males; 466 females).Results:Girls obese at 11 years had lower academic attainment at 11, 13 and 16 years compared with those of a healthy weight, even after controlling for a wide range of confounders. Associations between obesity and academic attainment were less clear in boys. The potential mediating effects of depressive symptoms, intelligence quotient (IQ) and age of menarche in girls were explored, but when confounders were included, there was no strong evidence for mediation.Conclusions:For girls, obesity in adolescence has a detrimental impact on academic attainment 5 years later. Mental health, IQ and age of menarche did not mediate this relationship, suggesting that further work is required to understand the underlying mechanisms. Parents, education and public health policy makers should consider the wide reaching detrimental impact of obesity on educational outcomes in this age group.

Highlights

Systematic reviews on the impact of child and adolescent obesity have reported a wide variety of adverse consequences, in both the short and long term.[1,2] Some evidence for a long-term adverse impact of childhood obesity on adult educational attainment and adult income was reported in the earliest of the systematic reviews on the consequences of childhood obesity; only two older studies were identified, one from the United States and the other from the United Kingdom.[1]
Confounding variables from the fully adjusted model were included in the analyses; the results show the extent to which depressive symptoms and intelligence quotient (IQ) mediate the relationship between weight status and academic attainment at 16 years old, while taking into account the full range of confounding variables
The estimates and associated confidence intervals for the indirect effects demonstrate that neither depressive symptoms nor IQ mediated the relationship between weight status at 11 years and academic attainment at 16 years old for males or females

Summary

Introduction

Systematic reviews on the impact of child and adolescent obesity have reported a wide variety of adverse consequences, in both the short and long term.[1,2] Some evidence for a long-term adverse impact of childhood obesity on adult educational attainment and adult income was reported in the earliest of the systematic reviews on the consequences of childhood obesity; only two older studies were identified, one from the United States and the other from the United Kingdom.[1]. While 29 eligible studies were included in this systematic review,[3] almost all were based on samples from the United States and so not internationally representative. The review by Caird et al.[3] noted that few studies had addressed the potential mediators of any relationships between child or adolescent obesity and academic attainment. Since the publication of the review by Caird et al.,[3] few robust studies which address the weaknesses identified in the evidence base have been published.

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Conclusion