Percentile distribution of the waist circumference among Mexican pre-adolescents of a primary school in Mexico City.

AIM: The aim of this study is to describe the percentile distribution of the waist circumference in Mexican pre-pubertal children living in an urban, middle-income area. METHODS: Children, aged 6-10, from a primary school, located in a middle-income area in Mexico City were included (n=833). Anthropometric measurements were made in the case of all children by using standardized procedures. RESULTS: The prevalence of obesity and overweight was greater among boys (p<0.001). Of them, 30 were obese (7.2%) and 47 were overweight (11.4%). Girls had a prevalence of obesity of 2.8% and of overweight of 8.8%. Boys had greater waist circumference than girls (p<0.001). This observation was independent from differences in age or body mass index (BMI). The distribution of the waist circumference was shifted towards higher values among boys. The values corresponding to the 85th percentile ranged, in boys aged 6-10, between 62.9 and 85.9 cm. By contrast, for girls, those values were 66.8 and 72.08 cm, respectively. A receiver-operator curve was constructed in order to identify the waist circumference most likely to be associated with a BMI of > 85th percentile. We found that age- and sex-specific cut-off points are required for the detection of central adiposity in children aged 6-10. CONCLUSIONS: The percentile distribution of the waist circumference in Mexican pre-pubertal children living in urban, middle-income areas is described in this study. Moreover, included are the cut-off points most likely to be associated with increased adiposity. This information can be used for defining abdominal obesity in paediatric populations.