title: Accuracy of anthropometric measurements in estimating fat mass in individuals with 21-hydroxylase deficiency.
abstract: OBJECTIVE
  The use of anthropometric measurements to estimate the percentage of body fat (%BF) is easy and inexpensive. However, the accuracy of these methods in patients with 21-hydroxylase deficiency (21OHD) has not been explored. The objective of this study was to evaluate the accuracy of skinfold-based models, body mass index (BMI), and waist circumference (WC) in estimations of %BF using dual-energy X-ray absorptiometry (DXA) as the reference method in individuals with 21OHD.
  
  
  METHODS
  Fifty-four 21OHD patients (32 women and 22 men), aged 7 to 20 y, were recruited for the study. DXA was used to determine %BF; four predictive skinfold equations, BMI, and WC were assessed for accuracy in determining %BF.
  
  
  RESULTS
  All predictive skinfold equations were highly associated (R, range: 0.82-0.89) with DXA %BF values. In women, BMI and WC showed moderate correlations (R = 0.69 for both BMI and WC) with DXA values. In contrast, among men there was a low explanatory power for BMI (13%) and WC (4%) and high errors (BMI, 6.9%; WC, 7.4%). All predictive equations significantly underestimated %BF (range of differences, -4.1 to -8.9) compared with DXA (women, 31.3 ± 6.1; men, 24.4 ± 7.3), and large limits of agreement were observed (range, -15.3 to 1.7 and -15.5 to 4.2 for women and men, respectively).
  
  
  CONCLUSIONS
  In children and adolescents with 21OHD, %BF as estimated by skinfold measurements was associated more strongly with DXA-assessed %BF than both BMI and WC. However, still, the skinfold-based assessment underestimated DXA %BF and showed moderate agreement.
authors.affiliation: Growth and Body Composition Laboratory, Center for Investigation in Pediatrics-CIPED, Faculty of Medical Sciences-FCM, State University of Campinas-UNICAMP, Campinas, São Paulo, Brazil. ezequiel@fcm.unicamp.br
authors.forename: Ezequiel Moreira
authors.initials: EM
authors.lastname: Gonçalves
authors.forename: Analiza M
authors.initials: AM
authors.lastname: Silva
authors.forename: Diana A
authors.initials: DA
authors.lastname: Santos
authors.forename: Sofia Helena Valente
authors.initials: SH
authors.lastname: Lemos-Marini
authors.forename: Allan
authors.initials: A
authors.lastname: de Oliveira Santos
authors.forename: Carolina Taddeo
authors.initials: CT
authors.lastname: Mendes-Dos-Santos
authors.forename: Maricilda Palandi
authors.initials: MP
authors.lastname: De-Mello
authors.forename: Gil
authors.initials: G
authors.lastname: Guerra-Júnior
mesh_terms: D015502:Absorptiometry, Photon; D000273:Adipose Tissue; D000293:Adolescent; D000312:Adrenal Hyperplasia, Congenital; D000328:Adult; D000886:Anthropometry / Q000379:methods*; D001823:Body Composition; D015992:Body Mass Index; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D055641:Mathematical Concepts; D015203:Reproducibility of Results; D012737:Sex Factors; D012885:Skinfold Thickness; D013255:Steroid 21-Hydroxylase / Q000378:metabolism*; D055105:Waist Circumference; D055815:Young Adult
chemical_list: D013255:Steroid 21-Hydroxylase