title: Obesity impairs academic attainment in adolescence: findings from ALSPAC, a UK cohort.
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.
  
  
  METHODS
  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.
  
  
  METHODS
  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.
authors.affiliation: School of Psychology, University of Dundee, Dundee, UK.
authors.forename: J N
authors.initials: JN
authors.lastname: Booth
authors.affiliation: University of Georgia, Athens, GA, USA.
authors.forename: P D
authors.initials: PD
authors.lastname: Tomporowski
authors.affiliation: University of Strathclyde, Glasgow, UK.
authors.forename: J M E
authors.initials: JM
authors.lastname: Boyle
authors.affiliation: University of Bristol, Bristol, UK.
authors.forename: A R
authors.initials: AR
authors.lastname: Ness
authors.affiliation: University of Bristol, Bristol, UK.
authors.forename: C
authors.initials: C
authors.lastname: Joinson
authors.affiliation: University of Bristol, Bristol, UK.
authors.forename: S D
authors.initials: SD
authors.lastname: Leary
authors.affiliation: University of Strathclyde, Glasgow, UK.
authors.forename: J J
authors.initials: JJ
authors.lastname: Reilly
mesh_terms: D000124:Achievement; D000293:Adolescent; D015992:Body Mass Index; D002648:Child; D015331:Cohort Studies; D004522:Educational Status; D005260:Female; D006801:Humans; D007360:Intelligence; D008137:Longitudinal Studies; D008297:Male; D063766:Pediatric Obesity / Q000150:complications / Q000503:physiopathology* / Q000523:psychology; D011627:Puberty; D017678:Sex Distribution; D013997:Time Factors; D006113:United Kingdom / Q000453:epidemiology