A 360-degree overview of body composition in healthy people: Relationships among anthropometry, ultrasonography, and dual-energy x-ray absorptiometry

Objective: The aim of this study was to test the relationship between anthropometry, ultrasonography, and dual-energy x-ray absorptiometry (DXA) for the assessment of body composition in clinical practice. Methods: The study was carried out in Italian blood donor volunteers belonging to five different age groups (18-70 y old; 25 men and 25 women per group; N = 250 participants; n = 125 men, n = 125 women). A complete history was collected and routine blood analyses were performed to confirm healthy status. All participants were submitted to whole-body DXA (tricompartmental analysis, regional, and total body), ultrasonography (abdominal adiposity evaluation), and anthropometric measurements. DXA was used as gold standard and its biomarkers were taken as reference for fat-lean mass balance, central-peripheral fat distribution, central or visceral fat, and subcutaneous fat. Results: Anthropometric and ultrasound parameters were closely associated with most of DXA parameters. Composite markers representative of central and abdominal visceral fat compartments were significantly correlated with waist circumference, waist-to-hip ratio, and intra-abdominal fat thickness by ultrasound, in both men and women (P <0.025). As expected, subcutaneous depots were significantly correlated with maximum subcutaneous fat thickness measured by ultrasonography (P <0.025). Conclusions: Both anthropometry and ultrasonography provide a reliable estimate of visceral adipose tissue in a non-obese population compared with DXA, whereas anthropometry prediction of subcutaneous adiposity is weak. Physicians should be aware of the limits of these techniques for the assessment of body composition.