Relationship of total body fatness and five anthropometric indices in Chinese aged 20–40 years: different effects of age and gender

Abstract

We aim to evaluate the ethnic-specific relationship of total fat mass and anthropometric indices in Chinese. Cross-section study. This study was performed at the College of Life Sciences, Hunan Normal University, P.R. China. To increase our understanding of the relationship of total fat mass and anthropometric indices in Chinese, 793 females and 1091 males aged 20-40 years were randomly recruited from Changsha city of P. R. China. Hip circumference (HC) and waist circumference (WC) were measured using standardized equipments, and other three anthropometric indices of body mass index (BMI), waist-to-hip ratio (WHR), and conicity index (CI) were calculated using weight, height, HC and WC. Total body fatness (TBF) in kg was measured using a Hologic QDR 4500 W dual-energy X-ray absorptiometry (DEXA) scanner. There was an increasing trend of TBF, %TBF (percent total body fatness) and the five anthropometric indices in successively older age groups. Compared with females, males generally had high average BMI, WC, HC, WHR and CI, but had low average TBF and %TBF. Except for some correlations in 25-29 years age groups, TBF and %TBF were significantly correlated with five anthropometric indices with the Pearson's correlation coefficients ranging from 0.07 to 0.87. Principal component analysis (PCA) was performed to form four principal components (PCs) that interpreted over 99% of the total variation of the five related anthropometric indices in all age groups, with over 53% of the total variation accounted for by the PC1. Multiple regression analyses showed that four PCs combined explained a greater variance (R (2)=55.2-80.8%) in TBF than did BMI alone (R (2)=40-74.9%). Our results suggest that there is an increasing trend of total fat mass and five anthropometric indices with aging; that age and sex have the important effects on influencing the correlations of TBF and the studied anthropometric indices; and that the accuracy of predicting the TBF using five anthropometric indices is higher than using BMI alone.