Recent dynamics suggest selected countries catching up to US obesity

Abstract

Background: The United States has been the country with the highest body mass indexes (BMIs; in kg/m(2)) at higher centiles, but research that compares the United States with other nations is lacking.

Objective: To present a picture of global obesity and examine the shifts in BMI in children, I examined BMI data for men and women at the upper ends of the BMI distributions in Australia, China, the United Kingdom, and the United States.

Design: As representative data, I used directly measured weight and height for children aged 6-18 y and for men and women aged > or =19 y. Quantile regression analysis with BMI was used to determine the outcome, and the coefficients of age, age squared, and age cubed represented the explanatory variables plotted to determine mean BMI at the 95th centile for each age group. Overweight and obesity measures across all selected countries, with the use of nationally representative surveys and the 95th centile mean BMI, were determined.

Results: Among women, much larger increases were found in mean BMI at the 95th percentile in Australia (+5.7 BMI units) and the United Kingdom (+3.7 BMI units) than in the United States (+2.7 BMI units) in one-half the time. In contrast, among children, younger Chinese children experienced the largest increase. For example, the mean BMI at the 95th centile for 6-y-old Chinese children is 24.8 (a 5.0 increase), which is 2.6 BMI units more than the BMI at the 95th centile for children in the United States.

Conclusions: Among children, BMIs for US children at the 95th centile are below those in China, whereas among women, Australian and UK women are rapidly approaching BMIs found in US women.

FIGURE 1

A, B: Shift in the BMI (in kg/m²) distribution in the United States, 1971–2006 (percentage of the population at each BMI point). Source: NHANES (National Health and Nutrition Examination Survey; 1971–1975, 1988–1994, and 2003–2006) data weighted to be nationally representative.

FIGURE 2

Trends in the BMI level (in kg/m²) at the 95th centile in the United States.

FIGURE 3

Shift in BMI levels (in kg/m²) at the 95th centile for women aged 30 y. Results are on the basis of quantile regression using age and age squared (when significant).

FIGURE 4

Shift in BMI levels (in kg/m²) at the 95th centile for children aged 6 y. Results are on the basis of quantile regression using age and age squared (when significant).