Reference centiles for evaluating total body fat development and fat distribution by dual-energy x-ray absorptiometry among children and adolescents aged 3-18 years.

BACKGROUND & AIMS: The rise in the prevalence of childhood obesity has increased the demand for accurately evaluating body fatness in pediatric population. The aim of this study was to provide a series of sex- and age-specific body fat reference centiles for evaluating total body fat development and fat distribution in Chinese children and adolescents using dual-energy x-ray absorptiometry (DXA).

METHODS

A nationwide sample of Chinese children and adolescents aged 3-18 years (n = 12,790) was drawn from a cross-sectional survey of the China Child and Adolescent Cardiovascular Health study (2013-2019). Fat measurements, including total fat mass index (FMI), total body fat percentage (BF%), regional FMI, trunk to leg (T/L) fat ratio and android to gynoid (A/G) fat ratio, were derived from whole body DXA scans. Sex- and age-specific centiles were estimated using the lambda-mu-sigma method and then compared with values derived from the US National Health and Nutrition Examination Survey (1999-2004) and Korean National Health and Nutrition Examination Survey (2008-2011).

RESULTS

During early childhood, almost all body fat parameters decreased with age, except an increase in A/G ratio. After 7 years onward, drastic upward trends of total FMI and BF% were exhibited in boys till 10 years, followed by opposite downward trends during 11-14 years; while sustained increase of FMI was shown in girls across ages accompanied by relatively constant BF% levels. Meanwhile, steady increases were noticed for A/G ratio and T/L ratio, which were more pronounced in boys. In addition, the proposed body fat references were much lower than the US but similar to Koreans despite of subtle differences.

CONCLUSIONS

This is the first study to present a set of DXA-based body fat reference for Chinese children and adolescents aged 3-18 years. The new reference provides clinicians and researchers a useful tool for assessing body fat development and distribution patterns throughout early childhood and adolescence.