Key Words: Obesity, overweight, school achievement, cognitive, child, adolescent
Do lifestyle interventions improve school achievement, cognitive function and/or future success in overweight or obese children and adolescents?
Excess body fat is associated with a wide range of adverse physical and mental health conditions. Childhood obesity is increasing worldwide, with implications for current and future health and social wellbeing. There is some evidence that overweight status is associated with poorer cognitive scores, lower educational attainment, and later life unemployment. Currently, lifestyle changes are recommended to prevent and manage obesity; however, the effect of such interventions on school attainment is unknown.
This summary is based on a Cochrane systematic review with meta-analyses on six randomised controlled trials (published in 14 papers). Included studies collected data from 674 overweight and obese 3-18 year olds (defined by age and gender-specific Body Mass Index measures or waist circumference). Lifestyle interventions were included if they increased physical activity, psychological support, reduced calorie intake and sedentary behaviour. The primary review outcome was school attainment recorded by trained staff, measured by (i) global performance; (ii) performance on a specific test; or (iii) special educational class need or use. Secondary outcomes related to measures of cognitive function.
Summary of Key Evidence:
- Four studies assessed school achievement outcomes. One study (moderate quality) which combined lifestyle education with a dietary intervention achieved statistically significantly improved global school achievement scores (Mean Difference (MD) 1.78, 95% confidence interval (CI) 0.8-2.76; n=321). However, when this study was combined in meta-analysis with a study of higher risk of bias no combined effect was determined. Significant ‘mathematics achievement’ improvement was noted in one physical activity trial (MD= 3, 95%CI 0.78 to 5.22; n=96, high quality evidence); however, when this study was included in a meta-analysis with lesser quality evidence, no statistical improvement was determined. No trial effect was found for reading, vocabulary and language improvement; and no study investigated special educational class need/use or writing attainment.
- Three studies investigated lifestyle effects on five different measures of cognitive performance. Statistically significant cognitive improvements were noted on executive function (MD=3.4, 95%CI 0.62 to 6.22; n=170 in a meta-analysis combining two trials) and working memory (MD=3, 95%CI 0.51 to 5.49; n=116, one study). No evidence was found for improvement in attention, inhibitory control and simultaneous processing skills.
Best Practice Recommendations:
Currently there is a lack of evidence about the effect of paediatric obesity or overweight lifestyle interventions on school achievement and cognitive skills. Researchers should consider measuring school attainment-type outcomes in future child or adolescent lifestyle intervention trials.
Janice Christie, PhD, MA, RN, RSCPHN
Senior lecturer/programme manager
School of Health Science
City University London
A member of the Cochrane Nursing Care Field (CNCF)
Martin A, Saunders DH, Shenkin SD, Sproule J. (2014). Lifestyle intervention for improving school achievement in overweight or obese children and adolescents. Cochrane Database of Systematic Reviews, 3(CD009728). DOI:10.1002/14651858.CD009728.pub2.
Available at: http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD009728.pub2/pdf