title: Computed tomography-based validation of abdominal adiposity measurements from ultrasonography, dual-energy X-ray absorptiometry and anthropometry.
abstract: Large-scale aetiological studies of obesity and its pathological consequences require accurate measurements of adipose mass, distribution and subtype. Here, we compared the validity of three abdominal obesity assessment methods (dual-energy X-ray absorptiometry (DXA), ultrasound and anthropometry) against the gold-standard method of computed tomography (CT) in twenty-nine non-diseased middle-aged men (BMI 26.5 (sd 3.1) kg/m(2)) and women (BMI 25.5 (sd 3.2) kg/m(2)). Assessments of adipose mass (kg) and distribution (total subcutaneous (TSAT), superficial subcutaneous (SSAT), deep subcutaneous (DSAT) and visceral (VAT)) were obtained. Spearman's correlations were performed adjusted for age and sex. VAT area that was assessed using ultrasound (r 0.79; P < 0.0001) and waist circumference (r 0.85; P < 0.0001) correlated highly with VAT from CT, as did BMI (r 0.67; P < 0.0001) and DXA (r 0.70; P < 0.0001). DXA (r 0.72; P = 0.0004), BMI (r 0.71; P = 0.0003), waist circumference (r 0.86; P < 0.0001) and ultrasound (r 0.52; P = 0.015) were less strongly correlated with CT TSAT. None of the comparison measures of DSAT was strongly correlated with CT DSAT (all r approximately 0.50; P < 0.02). BMI (r 0.76; P < 0.0001), waist circumference (r 0.65; P = 0.002) and DXA (r 0.75; P < 0.0001) were all fairly strongly correlated with the CT measure of SSAT, whereas ultrasound yielded a weaker yet statistically significant correlation (r 0.48; P = 0.03). Compared with CT, visceral and subcutaneous adiposity can be assessed with reasonable validity using waist circumference and BMI, respectively. Ultrasound or DXA does not generally provide substantially better measures of these traits. Highly valid assessments of DSAT do not appear to be possible with surrogate measures. These findings may help guide the selection of measures for epidemiological studies of obesity.
authors.affiliation: Genetic Epidemiology and Clinical Research Group, Department of Public Health and Clinical Medicine, Division of Medicine, Umeå University Hospital, Umeå 90 187, Sweden.
authors.forename: Anna M I
authors.initials: AM
authors.lastname: Gradmark
authors.forename: Anders
authors.initials: A
authors.lastname: Rydh
authors.forename: Frida
authors.initials: F
authors.lastname: Renström
authors.forename: Emanuella
authors.initials: E
authors.lastname: De Lucia-Rolfe
authors.forename: Alison
authors.initials: A
authors.lastname: Sleigh
authors.forename: Peter
authors.initials: P
authors.lastname: Nordström
authors.forename: Soren
authors.initials: S
authors.lastname: Brage
authors.forename: Paul W
authors.initials: PW
authors.lastname: Franks
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods; D050154:Adiposity; D000328:Adult; D000886:Anthropometry; D015992:Body Mass Index; D003952:Diagnostic Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D050152:Intra-Abdominal Fat / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D056128:Obesity, Abdominal / Q000000981:diagnostic imaging*; D018709:Statistics, Nonparametric; D050151:Subcutaneous Fat / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed / Q000379:methods; D014463:Ultrasonography; D055105:Waist Circumference