Establishing a standard definition for child overweight and obesity worldwide: international survey

Abstract

Objective: To develop an internationally acceptable definition of child overweight and obesity, specifying the measurement, the reference population, and the age and sex specific cut off points.

Design: International survey of six large nationally representative cross sectional growth studies.

Setting: Brazil, Great Britain, Hong Kong, the Netherlands, Singapore, and the United States.

Subjects: 97 876 males and 94 851 females from birth to 25 years of age.

Main outcome measure: Body mass index (weight/height(2)).

Results: For each of the surveys, centile curves were drawn that at age 18 years passed through the widely used cut off points of 25 and 30 kg/m(2) for adult overweight and obesity. The resulting curves were averaged to provide age and sex specific cut off points from 2-18 years.

Conclusions: The proposed cut off points, which are less arbitrary and more internationally based than current alternatives, should help to provide internationally comparable prevalence rates of overweight and obesity in children.

PIP: This study aimed to develop an internationally acceptable definition of child overweight and obesity, specifying the measurement, reference population, and age and sex specific cut off points. Data on body mass index (weight/height) were obtained from 6 large nationally representative cross sectional surveys on growth from Brazil, Great Britain, Hong Kong, the Netherlands, Singapore, and the US. The study included 97,876 males and 94,851 females from birth to 25 years of age. For each of the surveys, centile curves were drawn that at age 18 years passed through the widely used cut-off points of 25 and 30 kg/sq. m for adult weight and obesity. The resulting curves were averaged to provide age- and sex-specific cut-off points from 2 to 18 years. The proposed cut off points, which are less arbitrary and more internationally based than current alternatives, should help to provide internationally comparable prevalence rates of overweight and obesity in children.

Figure 1

Centiles for body mass index for British males and females. Centile curves are spaced two thirds of z score apart. Also shown are body mass index values of 25 and 30 kg/m² at age 18, with extra centile curves drawn through them

Figure 2

Median body mass index by age and sex in six nationally representative datasets

Figure 3

Centiles for overweight by sex for each dataset, passing through body mass index of 25 kg/m² at age 18

Figure 4

Centiles for obesity by sex for each dataset, passing through body mass index of 30 kg/m² at age 18

Figure 5

Plots of coefficient of variation of body mass index by age and sex for each dataset

Figure 6

International cut off points for body mass index by sex for overweight and obesity, passing through body mass index 25 and 30 kg/m² at age 18 (data from Brazil, Britain, Hong Kong, Netherlands, Singapore, and United States)

Figure 7

Centiles for overweight by sex for 11 datasets