Body composition reference ranges in community‐dwelling adults using dual‐energy X‐ray absorptiometry: the Australian Body Composition (ABC) Study
Ben Kirk, Ebrahim Bani Hassan, Sharon L. Brennan‐Olsen, Sara Vogrin, Stefanie Bird, Jesse Zanker, Steven Phu, Jarrod D. Meerkin, Steven B. Heymsfield, Gustavo Duque
Abstract
Abstract Background Reference ranges for lean mass (LM) and fat mass (FM) are essential in identifying soft tissue disorders; however, no such reference ranges exist for the most commonly used Hologic dual‐energy X‐ray absorptiometry (DXA) machine in Australia. Methods Cross‐sectional study of community‐dwelling adults (aged 18–88 years) who underwent a Hologic DXA scan at one of three commercialized densitometry centres in Australia. Age‐specific and sex‐specific percentile curves were generated for LM [LM, appendicular lean mass (ALM), ALM adjusted for height squared (ALM/h 2 ), and ALM adjusted for body mass index (ALM/BMI)] and FM [FM, FM adjusted for height squared (FM/h 2 ), appendicular fat mass, and android and gynoid fat] parameters using the LMS statistical method. Cutpoints equivalent to T ‐scores of −1, −2, and −2.5 standard deviations below the young mean reference group (20–29 years) were also generated for LM parameters. Results A total of 15 479 community‐dwelling adults (54% men) with a median age of 33 years (interquartile range: 28, 42) were included. LM, ALM, and ALM/h 2 remained stable until age 50, after which these parameters started to decline in both sexes. Compared with age 50, median percentiles of LM, ALM, and ALM/h 2 declined by −5.9 kg, −3.7 kg, and −0.86 kg/m 2 in men and by −2.5 kg, −1.8 kg, and −0.10 kg/m 2 in women at age 70, respectively. Adjusting ALM for BMI (rather than height squared) resulted in different trends, with ALM/BMI decreasing from as early as age 20. Compared with age 20, median percentiles of ALM/BMI at age 40 declined by −0.10 kg/kg/m 2 in men and by −0.06 kg/kg/m 2 in women; and at age 70, ALM/BMI declined by −0.25 kg/kg/m 2 in men and by −0.20 kg/kg/m 2 in women. Cutpoints equivalent to T ‐scores of −1, −2, and −2.5 standard deviations for ALM/BMI were 1.01, 0.86, and 0.77 kg/kg/m 2 in men and 0.70, 0.59, and 0.53 kg/kg/m 2 in women, respectively. All FM parameters progressively increased from age 20 and continued up until age 70. Conclusions We developed reference ranges for LM and FM parameters from Hologic DXA machines in a large cohort of Australian adults, which will assist researchers and clinicians in identifying soft tissue disorders such as obesity, sarcopenia, and cachexia.