Application of Body Mass Index to Schoolchildren of Mexico City

Abstract

Background: The validity of body mass index (BMI)-for-age for obesity diagnosis in Latin-American children may be limited due to observed cases of overweight without obesity (i.e. body fat excess), possibly due to certain physical characteristics. In the current study, we investigated whether the usefulness of BMI-for-age in the diagnosis of obesity among Mexican schoolchildren is modified by height, trunk length, muscle mass, body frame, or waist circumference. Methods: Our study cohort comprised 1,015 schoolchildren (aged 6–11 years) from Mexico City. Obesity diagnostics were derived from three classifications of BMI-for-age: percentiles of BMI according to the references of the Centers of Disease Control (CDC), the National Center for Health Statistics and the International Obesity Task Force. The area under the curve (AUC, through receiver-operating characteristic curves) and optimal cutoff points (by Youden index) of each classification were calculated. Body fat percentage, triceps skinfold thickness and blood pressure were used as standards. AUC and optimal cutoff point analysis were stratified according to height-for-age, sitting height, elbow breadth, arm muscle area (AMA) and waist circumference. Results: For the general population, the CDC reference had the highest values of AUC (0.94 for triceps skinfold thickness and 0.96 for body fat percentage), and the optimal cutoff point was the 85th percentile. Among schoolchildren with large body frames (measured through elbow breadth) or with high muscle mass (assessed by AMA), the optimal cutoff point was the 95th percentile of the CDC reference. Conclusions: Our results suggest that the percentile cutoff to define obesity in children with high muscle mass or a large body frame should be the 95th percentile, while the 85th percentile can still be used for the other children.

Body frame size in school children is related to the amount of adipose tissue in different depots but not to adipose distribution

“…Correlations between body frame size and AT depot‐specific measures support the hypothesis of Henneberg and Ulijaszek () that larger trunk frames reflect larger gastrointestinal systems that supply the body with greater amounts of nutrients, thus producing positive energy balance and resulting in greater storage of subcutaneous fat. There is evidence that the optimal percentile cutoff to define obesity in children differs between those with high muscle mass or a large body frame (Ortiz‐Hernández et al, ).…”

“…Henneberg and Ulijaszek () suggested that larger body frames are associated with greater adipose storage, and Ortiz‐Hernandez recommended that the optimal percentile cutoff to define obesity in children differs among different body frame dimensions (Ortiz‐Hernández, López Olmedo, Genis Gómez, Melchor López, & Valdés Flores, ). The main aim of this study was to test the hypothesis that body frame size is related to the amount of fat in different adipose tissue depots and to fat distribution in schoolchildren.…”

Growth status among low‐income Mexican and Mexican‐American elementary school children

“…In comparison to non-Hispanic whites and non-Hispanic blacks, Mexican-American children tend to be shorter and have higher skinfold measures (Martorell et al, 1987;Ortiz-Hernandez et al, 2008). Children who have experienced growth stunting and have disproportionate trunk and leg length as a result may have a higher BMI percentile because of a shorter total height (Bogin and Rios, 2003).…”