title: Reliability and intermethod agreement for body fat assessment among two field and two laboratory methods in adolescents.
abstract: To increase knowledge about reliability and intermethods agreement for body fat (BF) is of interest for assessment, interpretation, and comparison purposes. It was aimed to examine intra- and inter-rater reliability, interday variability, and degree of agreement for BF using air-displacement plethysmography (Bod-Pod), dual-energy X-ray absorptiometry (DXA), bioelectrical impedance analysis (BIA), and skinfold measurements in European adolescents. Fifty-four adolescents (25 females) from Zaragoza and 30 (14 females) from Stockholm, aged 13-17 years participated in this study. Two trained raters in each center assessed BF with Bod-Pod, DXA, BIA, and anthropometry (DXA only in Zaragoza). Intermethod agreement and reliability were studied using a 4-way ANOVA for the same rater on the first day and two additional measurements on a second day, one each rater. Technical error of measurement (TEM) and percentage coefficient of reliability (%R) were also reported. No significant intrarater, inter-rater, or interday effect was observed for %BF for any method in either of the cities. In Zaragoza, %BF was significantly different when measured by Bod-Pod and BIA in comparison with anthropometry and DXA (all P < 0.001). The same result was observed in Stockholm (P < 0.001), except that DXA was not measured. Bod-Pod, DXA, BIA, and anthropometry are reliable for %BF repeated assessment within the same day by the same or different raters or in consecutive days by the same rater. Bod-Pod showed close agreement with BIA as did DXA with anthropometry; however, Bod-Pod and BIA presented higher values of %BF than anthropometry and DXA.
authors.affiliation: GENUD (Growth, Exercise, NUtrition and Development) Research Group, Universidad de Zaragoza, Zaragoza, Spain.
authors.forename: Germán
authors.initials: G
authors.lastname: Vicente-Rodríguez
authors.forename: Juan P
authors.initials: JP
authors.lastname: Rey-López
authors.forename: Maria I
authors.initials: MI
authors.lastname: Mesana
authors.forename: Eric
authors.initials: E
authors.lastname: Poortvliet
authors.forename: Francisco B
authors.initials: FB
authors.lastname: Ortega
authors.forename: Angela
authors.initials: A
authors.lastname: Polito
authors.forename: Eniko
authors.initials: E
authors.lastname: Nagy
authors.forename: Kurt
authors.initials: K
authors.lastname: Widhalm
authors.forename: Michael
authors.initials: M
authors.lastname: Sjöström
authors.forename: Luis A
authors.initials: LA
authors.lastname: Moreno
mesh_terms: D015502:Absorptiometry, Photon; D000273:Adipose Tissue; D000293:Adolescent; D000704:Analysis of Variance; D001823:Body Composition; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D017097:Electric Impedance; D005260:Female; D006801:Humans; D008297:Male; D010991:Plethysmography; D015203:Reproducibility of Results; D012885:Skinfold Thickness; D013548:Sweden / Q000453:epidemiology; D044465:White People