Obese adolescent girls have lower academic attainment levels throughout their teenage years, according to a new study. The results of the research conducted by the Universities of Dundee, Strathclyde, Georgia and Bristol showed that girls who were obese, as measured by BMI (body mass index) at age 11 had lower academic attainment at 11, 13, and 16 years when compared to those with healthy weight.
Attainment in the core subjects of English, Maths and Science for obese girls was lower by an amount equivalent to a D instead of a C, which was the average in the sample.
There is a clear pattern which shows that girls who are in the obese range are performing more poorly than their counterparts in the healthy weight range throughout their teenage years, said Dr Josie Booth of the School of Psychology at the University of Dundee.
The research is the most comprehensive study yet carried out into the association between obesity and academic attainment in adolescence.
The results are published in the International Journal of Obesity.
The study took into account possible mediating factors but found that these did not affect the overall results.
The study examined data from almost 6000 children from the Avon Longitudinal Study of Parents and Children (ALSPAC), including academic attainment assessed by national tests at 11, 13 and 16 years and weight status.
71.4 per cent were healthy weight (1935 male, 2325 female), 13.3 per cent overweight (372 male, 420 female) and 15.3 per cent obese (448 male, 466 female).
Associations between obesity and academic attainment were less clear in boys.
Prof John Reilly, University of Strathclyde, the Principal Investigator of the study, said, "further work is needed to understand why obesity is negatively related to academic attainment, but it is clear that teenagers, parents, and policymakers in education and public health should be aware of the lifelong educational and economic impact of obesity."
The researchers took into account potentially distorting factors such as socio-economic deprivation, mental health, IQ and age of menarche (onset of the menstrual cycle) but found these did not change the relationship between obesity and academic attainment.