Mediators of the association between childhood BMI and educational attainment: analysis of a UK prospective cohort study

BackgroundHigher BMI in childhood is associated with lower academic achievement. ObjectiveTo explore potential pathways linking childhood BMI with educational attainment. MethodsIn the Avon Longitudinal Study of Parents and Children prospective cohort study (N=6234), we used structural equation models to assess the association between BMI z-scores at 11.7 years and educational attainment at 16 (General Certificate of Secondary Education (GCSE) results). Depressive symptoms, externalising symptoms, bullying, pressure to lose weight, and school enjoyment were considered as potential mediators. ResultsHigher BMI z-scores were associated with lower GCSE scores (total effect: females {beta} = -3.20 95% CI -5.15, -1.26; males {beta} = -2.98 95% CI -5.12, -0.84). Depressive symptoms and externalising symptoms partially mediated this association in females (indirect effect: {beta} = -0.35 95% CI -0.63, -0.06, proportion mediated = 11%; {beta} = -0.84 95% CI -1.77, 0.10, proportion mediated = 26%, respectively). In males, there was some evidence that the association was partially mediated by bullying (indirect effect {beta} = -0.35 95% CI -0.74, 0.03, proportion mediated = 12%). ConclusionsThe association between childhood BMI and educational attainment may be partially mediated by depressive symptoms and externalising symptoms in females, and by bullying in males.