Body fat variation and redistribution across different stages of life measured by dual-energy x-ray absorptiometry

Background: The global obesity epidemic of all ages has increased the demand for accurate management of body fat in each stage of life. The primary aim of this study was to provide reference centiles of body fat indices for Chinese children and adults and compare those with ethnicities from USA using dual-energy x-ray absorptiometry (DXA). Methods: The samples were drawn from two nationwide cross-sectional surveys of China Body Composition Life-course Study (2013-2023) and the US National Health and Nutrition Examination Survey (2011-2018). Age- and sex-specific centile curves were generated for a set of fat measurements, including total fat mass (FM), fat mass index (FMI), body fat percentage (BF%), trunk-to-leg fat ratio (TLR), android-to-gynoid fat ratio (AGR) and visceral-to-subcutaneous fat ratio (VSR), using the general additive model for location scale and shape method. Results: The age-related variations from childhood to adulthood were generally similar among Chinese, Non-Hispanic Whites, Non-Hispanic Blacks and Mexican American population, with distinct levels across races and ethnicities. For whole-body fat (FM, FMI, and BF%), Mexican American population consistently presented the highest levels before 40 years old, followed by Non-Hispanic White, Non-Hispanic Black and Chinese individuals. For central fats indices, although the TLR and AGR levels in Chinese males were second to Mexican American counterparts in most stages of life, the VSR was much higher in Chinese than other races and ethnicities from eight years old. Conclusions: DXA-based centiles for body fat quantity and distribution in Chinese population aged 3-60 years old were presented, and their differences with other race and ethnicity were noted across periods from early childhood to middle adulthood. Our findings will promote age-, sex- and ethnic-specific assessment of life-course body fat and obesity-related risks in clinical practice.