The global childhood obesity epidemic and the association between socio-economic status and childhood obesity

Figures & data

Table 1. Prevalence (%) of overweight and obesity in school-age children based on available data and IOTF criteria, and estimated for 2006 and 2010.

	Most recent surveys		Projected 2006^a		Projected 2010^a
WHO region (dates of most recent surveys)	Overweight and obesity	Obesity	Overweight and obesity	Obesity	Overweight and obesity	Obesity
Africa (1987–2003)	1.6	0.2	*	*	*	*
Americas (1988–2002)	27.7	9.6	40.0	13.2	46.4	15.2
Eastern Mediterranean (1992–2001)	23.5	5.9	35.3	9.4	41.7	11.5
Europe (1992–2003)	25.5	5.4	31.8	7.9	38.2	10.0
South-east Asia (1997–2002)	10.6	1.5	16.6	3.3	22.9	5.3
West Pacific (1993–2000)	12.0	2.3	20.8	5.0	27.2	7.0

Data source: Wang and Lobstein (2006).

*There were insufficient data on school age children in the WHO African region to make estimates of projected prevalence rates.

^aBased on population weighted annualised increases in prevalence.

Table 2. Combined childhood overweight and obesity prevalence (%) based on data collected since around the year 2000 for selected countries by WHO region.^a

	Year of survey	Age (years)	Boys	Girls	BMI reference
WHO Africa region
Algeria	2006	6–10	7.4	7.4	IOTF
Seychelles	2004–2005	9–15	16.5	21.0	IOTF
South Africa	2001–2004	6–13	13.6	17.7	IOTF
WHO Americas region
Brazil	2002	7–10	23.1	21.1	IOTF
Canada	2004	2–19	28.9	26.6	2000 CDC
Chile	2002	6	28.6	27.1	IOTF
Mexico	2006	2–19	28.4	27.3	2000 CDC
USA^b	2009–2010	2–19	33.0	30.4	2000 CDC
WHO eastern Mediterranean region
Egypt	2005	10–17	23.4	29.6	85th percentile
Iran	2003–2004	6–18	14.4	14.0	IOTF
Kuwait	1999–2000	10–14	44.7	44.9	NCHS
Saudi Arabia	2002	1–18	16.7	19.4	IOTF
United Arab Emirates (UAE)	1998–1999	5–17	32.4	32.4	IOTF
WHO European region
England	2007	5–17	22.7	26.6	IOTF
France	2006/7	3–17	13.1	14.9	IOTF
Germany	2008	4–16	22.6	17.7	IOTF
Netherlands	2003	5–16	14.7	17.9	IOTF
Switzerland	2007	6–13	16.7	13.1	IOTF
WHO south-east Asia region
India^c	2007–8	2–17	20.6	18.3	IOTF
India^d	2005–6	< 5	1.7	1.4	2006 WHO growth standard
Malaysia	2002	7–10	9.7 (obesity)	7.1 (obesity)	WHO
Sri Lanka	2003	10–15	1.7	2.7	IOTF
Vietnam	2004	11–16	11.7 (boys and girls)		IOTF
WHO western Pacific region
Australia	2007	2–16	22.0	24.0	IOTF
China^e	2005	7–18	14.9	8.9	Ji & Working Group on Obesity in China, 2005
Japan	1996–2000	6–14	16.2	14.3	IOTF
New Zealand	2007	5–14	28.2	28.8	IOTF
South Korea^f	2005	10–19	21.7	17.1	Moon et al., 2008

^aSome prevalence data was limited by data availability; many rates presented here may not be nationally representative. Only data collected since 2000 were used and we report statistics for those countries with large population sizes within each region as examples. We also added some additional data (main data source: IASO, 2012).

^bWe updated the rates based on more recent results (Ogden et al., 2012).

^cThe rates were higher than other reported prevalence (Wang et al., 2009); and this might be due to sample differences.

^dWe added the rates based on results from a large nationwide sample (International Institute for Population Sciences and Macro International, 2007).

^eWe added the rates based on results from a large nationwide sample (Ji and Cheng, 2009).

^fWe updated the rates based on more recent results of a nationwide survey (Song et al., 2010).

Table 3. Time trends in the combined prevalence (%) of overweight and obesity in preschool-age children aged 0–5 years for the years from 1990 to 2010 and projections for 2015 and 2020, by United Nations (UN) region.^a

UN region and sub-region	1990	1995	2000	2005	2010	2015	2020
Global	4.2	4.6	5.1	5.8	6.7	7.8	9.1
Developing countries	3.7	4.0	4.5	5.2	6.1	7.2	8.6
Developed countries^b	7.9	8.8	9.7	10.6	11.7	12.9	14.1
Africa	4.0	4.7	5.7	6.9	8.5	10.4	12.7
East	3.9	4.4	5.1	5.8	6.7	7.6	8.7
Middle	2.5	3.4	4.7	6.4	8.7	11.7	15.5
North	6.1	8.0	10.3	13.3	17.0	21.4	26.6
Southern	10.2	9.5	8.8	8.2	7.6	7.0	6.5
West	2.2	2.9	3.8	4.9	6.4	8.3	10.6
Asia^c	3.2	3.4	3.7	4.2	4.9	5.7	6.8
East	4.8	4.9	5.0	5.1	5.2	5.3	5.4
South central	2.3	2.6	2.9	3.2	3.5	3.9	4.3
South-east	2.1	2.6	3.1	3.8	4.6	5.6	6.7
West	3.0	4.5	6.8	10.1	14.7	21.0	29.1
Latin America and Caribbean	6.8	6.8	6.8	6.9	6.9	7.0	7.2
Caribbean	4.6	5.1	5.6	6.2	6.9	7.6	8.3
Central America	4.8	5.3	5.9	6.5	7.2	8.0	8.8
South America	8.0	7.7	7.4	7.1	6.8	6.5	6.3
Oceania^d	2.9	3.1	3.2	3.3	3.5	3.6	3.8

Data source: de Onis et al. (2010).

^aAll surveys included both boys and girls. Cross-sectional data on the prevalence of overweight and obesity were obtained from national nutrition surveys. A total of 450 nationally representative surveys were available from 144 countries. Of the 450 surveys, 413 were conducted in developing countries and 37 in developed countries. About 38% of the surveys (171 surveys) were conducted between 1991 and 1999, 16% (70 surveys) were conducted before 1991, and 46% (209 surveys) after 1999. Linear mixed-effects models were fit to estimate prevalence rates and numbers of affected children by region from 1990 to 2020. Overweight and obese statuses were defined based on > 2 standard deviations (SDs) from the weight-for-height median.

^bIncluding Europe, North America, Australia, New Zealand, and Japan.

^cExcluding Japan.

^dExcluding Australia and New Zealand.

Figure 1. (A) Worldwide prevalence of obesity in children and adolescents. (B) Worldwide combined prevalence of overweight and obesity in children and adolescents. The prevalence estimates were calculated as the arithmetic mean of the age-specific estimates. Adapted from Epidemiology of Obesity in Children and Adolescents (Pigeot et al., 2011, p. 228, Figure 13.2) with kind permission of Springer Science & Business Media.

Figure 2. Trends in the prevalence (%) of obesity (BMI ≥ 95th percentile) in US children and adolescents by age: 1971–1974 to 2009–2010. Based on national data collected in NHANES (Wang and Beydoun, 2007; Ogden et al., 2012).

Figure 3. Yearly average change in BMI (kg/m²), waist circumference (WC) (cm) and triceps skinfold thickness (TST) (mm) by their percentile distributions in US adolescents: 1988–1994 to 1999–2004. OLS estimate of average yearly shift within percentile groups based on NHANES III (1988–1994) and 1999–2004 data. Adapted from Beydoun & Wang (2010).

Figure 4. Trends in the prevalence (%) of overweight and obesity in Chinese school-age children, by gender: 1985–2005. Based on Chinese BMI cut-off points and data reported by Ji & Cheng (2008).

Figure 5. Association between family affluence and obesity in adolescent boys aged 11, 13 and 15 years from five countries: Example of overweight inequality regression lines. Data were collected from the Health Behavior in School-Aged Children study. Family affluence was measured as a function of family possessions (e.g. car ownership, number of computers, child had own bedroom) and number of family travels over the past year. Adapted by permission of Macmillan Publishers Ltd, International Journal of Obesity (Due et al., 2009, p. 1088, Figure 1).

Figure 6. Time trends in disparities of overweight prevalence by socio-economic status (SES) in US children and adolescents: 1971–1975 to 1999–2002. Obesity was defined as a BMI ≥ 95th percentile. The sample size in each National Health and Nutrition Examination Survey (NHANES) was: NHANES I (n = 6555), NHANES II (n = 6741), NHANES III (n = 9731), and NHANES 1999–2002 (n = 7390). Adapted by permission of the American Society for Nutrition from the American Journal of Clinical Nutrition (Youfa Wang & Qi Zhang, 2006, p. 709, Figure 1). *Significant between-group differences, P < 0.05 (chi-square tests).

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