Body composition analysis by DXA (dual X-ray absorptiometry) in Brazilian men: normative data.

Abstract

Considering ethnic and anthropometric differences, it is important to obtain specific normative data on body composition (BC) for each population. The objectives of this study were to obtain the normative curve for the BC of Brazilian men and to compare them to the North American male population. A total of 403 healthy Brazilian men 20years and older were included in the study. Data on concomitant diseases and physical activity were investigated using a structured questionnaire. Conditions that could affect lean and fat mass were excluded. BC was assessed via whole-body dual-energy X-ray absorptiometry (DXA) using a GE-Lunar device. Significance level was set as p<0.05. Mean age and body mass index (BMI) were 46.0±17.9years and 26.2±3.14kg/m2, respectively. Mean skeletal mass index (SMI), appendicular lean mass by BMI (ALMBMI), and fat mass index (FMI) were 8.38±0.85, 0.949±0.138, and 6.87±2.43kg/m2, respectively. There were negative associations among SMI (p<0.001), ALMBMI (p<0.001), and FMI (p=0.002) with age. Comparison with the National Health and Nutrition Examination Survey (NHANES) III data, originally performed with a Hologic device, showed that Brazilian men had lower FMI and BF. This difference was minimized after converting the NHANES results to the GE-Lunar database. Brazilian men had lower SMI than American men measured in NHANES III. FMI was less influenced by ethnicity than by BMI, and it could be used as a standard measure for assessing fat excess or adiposity. Our data suggest that conversion to each specific manufacturer's database should be performed to minimize differences in body composition between populations.