MEASUREMENT OF BODY COMPSITION IN TALL INDIVIDUALS USING DUAL-ENERGY X-RAY ABSORPTIOMETRY 212

Most dual-energy X-ray absorptiometers (DXA) used to assess fat mass, soft fat-free tissue (FFST), bone mineral content (BMC) and density (BMD) cannot completely scan subjects taller than ≈ 183 cm. Due to this limitation, subjects from the general population and some athletic groups have been precluded from body composition studies using DXA. The purpose of this investigation was to determine whether whole body fat mass, FFST, BMC and BMD could be accurately estimated in individuals taller than 183 cm from two, incomplete DXA scans. Twenty subjects (10 men and 10 women) shorter than 183 cm (mean = 171.5 cm) were scanned three times by DXA (Hologic QDR 1000/W, v. 5.55). The first scan (scan1) covered the entire body, the second scan(scan2) excluded the lower legs and the third scan (scan3) excluded the head. Head, trunk and arm measures from scan2 were combined with leg measures from scan3 to predict scan1. The summed measures from scan2 and scan3 accurately estimated scan1(Table 1). We conclude that accurate estimates of whole body composition can be obtained using DXA in individuals taller than 183 cm by summing two incomplete scans.