Childhood obesity

Abstract

Childhood obesity has important consequences for health and wellbeing both during childhood and also in later adult life. The rising prevalence of childhood obesity poses a major public health challenge in both developed and developing countries by increasing the burden of chronic non-communicable diseases. Despite the urgent need for effective preventative strategies, there remains disagreement over its definition due to a lack of evidence on the optimal cut-offs linking childhood BMI to disease risks, and limited evidence on the most effective components of interventions to prevent childhood obesity. This article reviews the trends in childhood obesity, its genetic, nutritional and other risk factors, and preventative and treatment strategies. Particular emphasis is given to early-onset obesity in pre-school children, which, as a precursor to later childhood and adult obesity, provides insights into the developmental and genetic origins of obesity and also offers the potential for early preventative approaches with long-lasting benefits.

Figure 1

Prevalence of obesity (BMI > 95^th centile) among children and adolescents aged 2-19 in the United States between 1971-74 to 2009-10 shows a recent plateau from 2003-04 onwards. Source: Based on data from the National Health and Nutrition Examination Survey (NHANES) published in Ogden et al., Health E-Stat 2010 and Ogden et al., Journal of the American Medical Association 2012 .

Figure 2

Recent plateau in the prevalences of obesity (BMI > 95^th centile) and ‘overweight or obesity’ (BMI > 85^th centile) among children aged 2-15 in England, 1995-2007 Source: Based on data published by the Association of Public Health Observatories

Figure 3

Trends between 1990-2010 and predicted ongoing rise 2010-2020 in the prevalence of BMI > +2 SD (equivalent to the 98^th centile) in preschool children in developed and developing countries. Source: Based on data published in de Onis et al., Public Health Nutrition 2010 ^,

Figure 4

Schematic summary of the complications of childhood obesity. Comorbidities of childhood obesity are depicted in the outer ring with their intermediate processes in the inner ring. Childhood obesity also increases the risk of adult obesity, which in turn also increases the likelihood of those comorbidities.

Figure 5

Odds ratio for childhood obesity by infant weight gain between 0-1 year, adjusted for sex, age and birth weight. Source: Figure reproduced from Druet et al, Paediatric and Perinatal Epidemiology, 2012

Figure 6

Comparison of the effect sizes on BMI Z-score in adults versus in children of various obesity-related genetic variants. The 12 single nucleotide polymorphism (SNP) risk allele score represents the effect of each additional obesity risk allele averaged across all 12 variants (error bars represent 95% CI). Source: Based on data published in den Hoed et al., Diabetes 2010