Clinical Review

# Obesity in children. Part 1: Epidemiology, measurement, risk factors, and screening

BMJ 2008; 337 (Published 15 October 2008) Cite this as: BMJ 2008;337:a1824
1. Ruth R Kipping, research fellow1,
2. Russell Jago, senior lecturer2,
3. Debbie A Lawlor, professor of epidemiology13
1. 1Department of Social Medicine, University of Bristol, Bristol BS8 2PS
2. 2Department of Exercise, Nutrition and Health Sciences, University of Bristol, Bristol BS8 1TP
3. 3MRC Centre for Causal Analysis in Translational Epidemiology, University of Bristol, Bristol BS8 2BN
1. Correspondence to: R Kipping ruth.kipping{at}bristol.ac.uk

#### Summary points

• Population changes in physical activity and diet are probably the main drivers of the obesity epidemic

• A complex interplay of genetics; epigenetics; and intrauterine, infancy, childhood, and family non-genetic factors may also be involved

• Obesity in children and adolescents is associated with metabolic and cardiovascular abnormalities and other adverse health outcomes

• Modifiable risk factors for childhood obesity are maternal gestational diabetes; high levels of television viewing; low levels of physical activity; parents’ inactivity; and high consumption of dietary fat, carbohydrate, and sweetened drinks

• Obesity is commonly measured in children by plotting body mass index on a standard growth chart to adjust for sex and age using a defined cut-off point

• Population screening for childhood obesity is not recommended

Obesity was first included in the international classification of diseases in 1948. Since then, an epidemic has developed internationally, affecting all age groups. This article describes the prevalence of obesity in children, its underlying risk factors, its consequences, and how it can be measured; it also discusses whether children should be screened for obesity. In a second article to be published next week we will discuss the prevention and management of obesity in children.1 The terms used are defined in box 1 (where authors of cited papers use terms differently we use the authors’ own words).

#### Sources and selection criteria

This review draws on the Foresight report, guidance from the National Institute of Health and Clinical Excellence, and a Cochrane review of preventing obesity.

In April 2008 we searched the Cochrane Library database of reviews and the Centre for Reviews and Dissemination databases using the search term “obesity”. We also conducted a Medline search ((Child$or paediatric or pediatric or adolescent) and (Obes$ or overweight)) limited to 1 January 2005 to 6 May 2008 and “review articles”; this identified 1105 articles. We read the abstracts …

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