Validity and reliability of dual-energy X-ray absorptiometry for the assessment of abdominal adiposity

Abstract

A number of methods exist for the estimation of abdominal obesity, ranging from waist-to-hip ratio to computed tomography (CT). Although dual-energy X-ray absorptiometry (DXA) was originally used to measure bone density and total body composition, recent improvements in software allow it to determine abdominal fat mass. Sixty-five men and women aged 18-72 yr participated in a series of studies to examine the validity and reliability of the DXA to accurately measure abdominal fat. Total body fat and abdominal regional fat were measured by DXA using a Lunar DPX-IQ. Multislice CT scans were performed between L1 and L4 vertebral bodies (region of interest) using a Picker PQ5000 CT scanner, and volumetric analyses were carried out on a Voxel Q workstation. Both abdominal total tissue mass (P = 0.02) and abdominal fat mass (P < 0.0001) in the L1-L4 region of interest were significantly lower as measured by DXA compared with multislice CT. However, Bland-Altman analysis demonstrated good concordance between DXA and CT for abdominal total tissue mass (i.e., limits of agreement = -1.56-2.54 kg) and fat mass (i.e., limits of agreement = -0.40-1.94 kg). DXA also showed excellent reliability among three different operators to determine total, fat, and lean body mass in the L1-L4 region of interest (intraclass correlations, R = 0.94, 0.97, and 0.89, respectively). In conclusion, the DXA L1-L4 region of interest compared with CT proved to be both reliable and accurate method to determine abdominal obesity.

Centrally located body fat is related to appetitive hormones in healthy postmenopausal women.

“…To assess central adiposity, one evaluator sectioned each wholebody DXA scan into waist, hip, and thigh regions based on bone landmarks ( Fig. 2) (19,24) and these regions were analyzed using special software (Discovery, version 12.3:7 Hologic Inc., Waltham, MA, USA). The waist region included the first lumbar through the fourth lumbar vertebrae.…”

“…Computed tomography is considered the gold standard in assessing centrally located fat, whereas dual-energy X ray absorptiometry (DXA) provides an accurate and reliable estimate of overall and regional body composition (19) with minimal radiation exposure. However, unlike computed tomography, DXA cannot differentiate between s.c. and visceral adipose tissue because measurements are only two dimensional.…”

“…However, unlike computed tomography, DXA cannot differentiate between s.c. and visceral adipose tissue because measurements are only two dimensional. Nevertheless, soft tissue analyses of DXA scans may be used to estimate visceral adipose tissue (20), as well as regional lean mass (21), by dividing the whole-body scan into subregions of interest (19).…”

Superiority of skinfold measurements and waist over waist-to-hip ratio for determination of body fat distribution in a population-based cohort of Caucasian Dutch adults

“…CFM/ PFM ratio, is a topic of great interest, especially population-based cohort studies, in which large numbers of subjects are measured, simple anthropometric measurements are needed to determine fat distribution. Dual-energy X-ray absorptiometry (DXA) is a well-accepted method and has a good concordance with computed tomography (CT) for the assessment of body fat (11). However, CT and DXA are costly and time consuming.…”

Association of ALOX15 gene polymorphisms with obesity-related phenotypes in Chinese nuclear families with male offspring

“…BMI has been widely used as a surrogate phenotype; however, it alone may not be sufficiently accurate to be used to indicate the proportion of fat in the body or the relative contributions of body muscle and fat [38] . DXA is a reliable and convenient method of assessing obesity and is considered the golden standard for anthropometric measures [39] . Although CT and MRI scans can also provide these measurements, those methods are limited by costs, radiation exposure and other factors [40] .…”