Obese kids as bright as thinner peers

13 July 2012

Obesity is not to blame for poor educational performance, according to early findings from research funded by the Economic and Social Research Council (ESRC). In a study that combines statistical methods with genetic information, researchers dispel the false idea that being overweight has damaging educational consequences.

Previous studies have shown that children who are heavier are less likely to do well at school. However, Dr Stephanie von Hinke Kessler Scholder from the University of York argues it’s vital to understand what drives this association. "We sought to test whether obesity 'directly' hinders performance due to bullying or health problems, or whether kids who are obese do less well because of other factors that are associated with both obesity and lower exam results, such as coming from a disadvantaged family," Dr Scholder explains.

Researchers examined data on almost 4,000 members of the Children of the 90s' Birth Cohort Study.  These data include the children's DNA. It is well known that genes are randomly allocated within a population, irrespective of factors such as socio-economic position. The researchers combined the latest developments from genetic epidemiology with statistical methodologies in economic and econometric research. Using two carefully chosen 'genetic markers', the research team was able to identify children with a slightly higher genetic pre-disposition to obesity.

"Based on a simple correlation between children's obesity as measured by their fat mass and their exam results, we found that heavier children did do slightly worse in school," Dr Scholder points out. "But, when we used children's genetic markers to account for potentially other factors, we found no evidence that obesity causally affects exam results. So, we conclude that obesity is not a major factor affecting children’s educational outcomes."

These findings suggest that the previously found negative relationship between weight and educational performance is driven by factors that affect both weight and educational attainment. Future research should focus on other determinants of poor educational outcomes, such as social class or a family's socio-economic circumstances, Dr Scholder points out.

The finding that obesity is not a cause of poorer educational performance is, the researchers suggest, a positive thing. "Clearly there are reasons why there are differences in educational outcomes, but our research shows that obesity is not one of them," Dr Scholder argues. 

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Notes for editors

  1. This release is based on the project 'The economics of childhood obesity' funded by the Economic and Social Research Councils and led by Dr Stephanie von Hinke Kessler Scholder, now of the Department of Economics and Related Studies, University of York, however this research was undertaken at Imperial College London.  The paper on which this release is based 'Genetic markers as instrumental variables: an application to child fat mass and academic achievement' can be viewed at: http://www.bristol.ac.uk/cmpo/publications/papers/2010/wp229.pdf
  2. Data is drawn from a sample of 3,729 children, participants in the Avon Longitudinal Study of Parents and Children (ALSPAC). Academic achievement is based on Key Stage 3 (KS3) scores. Children's body fat (adjusted for age in months, height and height squared) was measured by a dual-energy X-ray absorptiometry scan (DXA) at age 11. 
  3. The Economic and Social Research Council (ESRC) is the UK's largest organisation for funding research on economic and social issues. It supports independent, high quality research which has an impact on business, the public sector and the third sector. The ESRC’s total budget for 2012/13 is £205 million. At any one time the ESRC supports over 4,000 researchers and postgraduate students in academic institutions and independent research institutes. More at www.esrc.ac.uk