Body composition and its relationship with physical activity and anthropometric factors in Chinese adults.

To evaluate the relationship of body composition with physical activity and other anthropometric factors, a group of 437 healthy Chinese men and women were recruited. Body composition was measured using the bioelectric impedance technique. Levels of physical activity (LPA) were classified as light, moderate and heavy. Anthropometric factors evaluated included body mass index (BMI), ponderal index (PI), waist-to-hip ratio (WHR), triceps skinfold thickness (TSF), mid-arm circumference, mid-forearm circumference, arm muscle circumference (AMC) and arm muscle area (AMA). Sex was found to be highly associated with body composition, with females having a higher percentage of body fat and males having a higher percentage of body lean mass. This gender difference was independent of age, physical activity or other anthropometric factors. An increased level of physical activity was associated with higher body lean mass and lower body fat. Sex, LPA, TSF, PI and WHR were all entered into the regression equations to estimate body composition. Sex and physical activity have an independent effect on body composition and the commonly used estimators for adiposity and fat distribution such as BMI, PI, TSF and WHR are closely correlated with body composition.