Absence of differences related to sexin the values of the least significant changes for body composition by DXA in adult subjects

Abstract

Lack of gender-related differences in least significant changes for DXA body composition analysis in adult subjects
For longitudinal assessment of body composition by DXA, least significant changes (LSCs) should be calculated. It is unclear if there are gender differences for adult LSCs. With informed consent, 2 consecutive total-body DXA scans, with repositioning between them, were performed on 40 males and 40 females (age range 22 to 85 years) with a GE Lunar Prodigy Advance scanner, following the guidelines of the International Society for Clinical Densitometry (ISCD). All scans were obtained by the same skilled technologist. The LSCs were calculated according to the method proposed by the ISCD. Results were analyzed with GraphPad for Windows 6.0, with significance set at p < 0.05. There were no gender differences for age (p = 0.846) or body mass index (p = 0.802). Height, body mass, lean mass, and bone mineral content (BMC) were higher in males (all p < 0.0001), whereas fat mass was higher in females (p = 0.0036). There was no significant difference between genders for the coefficients of variation of fat mass (p = 0.0698), lean mass (p = 0.1483), or BMC (p = 0.5254). The LSCs (for a 95% CI) for fat mass were 1.780 kg (men), 1.671 kg (women), and 1.727 kg (both genders); for lean mass, 1.658 kg (men), 1.644 kg (women) and 1,651 (both genders); and for BMC, 112.2 g (men), 109.4 (women), and 110.8 g (both genders). These results suggest that LSCs for body composition of adult subjects can be calculated from either a sample of each gender or one that includes subjects of both genders.