title: Estimation of body fat in adults using a portable A-mode ultrasound.
abstract: OBJECTIVE
  This study aimed to develop and validate equations to estimate body fat based on anthropometric measurements of subcutaneous fat thickness (SFT) and muscle thickness (MT) measured by A-mode ultrasound (BodyMetrix) in Brazilian adults.
  
  
  METHODS
  Individuals (n = 206) underwent air-displacement plethysmography for body composition assessment. Arm, thigh, and calf circumferences were also obtained. SFT from triceps, biceps, subscapular, abdominal, thigh, and calf regions and MT from triceps, biceps, thigh, and calf regions were measured by BodyMetrix. Prediction equations were developed by stepwise multiple linear regression using the circumferences, weight, height, SFT, and MT. Lin's concordance correlation coefficient, mean difference, and 95% limits of agreement (95% LOA) were assessed in apparent and internal validity.
  
  
  RESULTS
  The prediction equation for whole-body fat for men included thigh circumference, triceps and thigh SFT, biceps MT, weight, and height. The equation for women included age, calf circumference, abdominal and calf SFT, weight, and height. The prediction equation overestimated men's whole-body fat by 0.5 percentual points, in average, and the lower and upper 95% LOA were -6.8% and 7.7%, respectively. For women, the prediction equation overestimated whole-body fat by 0.1 percentual points, in average. Lower and upper 95% LOA were -6.5% and 6.7%, respectively. Optimism-adjusted results using 500 repetitions with same size samples have shown similar results. Body fat extremes did not influence the whole-body fat estimation.
  
  
  CONCLUSIONS
  BodyMetrix A-mode ultrasound, in association with selected conventional anthropometric measurements, proved to be a reliable tool for the estimation of body fat percentage.
authors.affiliation: Post Graduate Program in Epidemiology, Federal University of Pelotas, Pelotas, Brazil; Nutrition College, Federal University of Pelotas, Pelotas, Brazil.
authors.forename: Renata M
authors.initials: RM
authors.lastname: Bielemann
authors.affiliation: Post Graduate Program in Health and Behavior, Catholic University of Pelotas, Pelotas, Brazil. Electronic address: cristinagbs@hotmail.com.
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Gonzalez
authors.affiliation: Post Graduate Program in Epidemiology, Federal University of Pelotas, Pelotas, Brazil.
authors.forename: Thiago Gonzalez
authors.initials: TG
authors.lastname: Barbosa-Silva
authors.affiliation: Nutrition College, Federal University of Pelotas, Pelotas, Brazil.
authors.forename: Silvana Paiva
authors.initials: SP
authors.lastname: Orlandi
authors.affiliation: Post Graduate Program in Epidemiology, Federal University of Pelotas, Pelotas, Brazil.
authors.forename: Mariana Otero
authors.initials: MO
authors.lastname: Xavier
authors.affiliation: Post Graduate Program in Health and Behavior, Catholic University of Pelotas, Pelotas, Brazil.
authors.forename: Rafaela Bülow
authors.initials: RB
authors.lastname: Bergmann
authors.affiliation: Post Graduate Program in Epidemiology, Federal University of Pelotas, Pelotas, Brazil.
authors.forename: Maria Cecília Formoso
authors.initials: MC
authors.lastname: Assunção
mesh_terms: D050154:Adiposity; D000328:Adult; D015992:Body Mass Index; D001835:Body Weight; D001938:Brazil; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging; D010991:Plethysmography; D015203:Reproducibility of Results; D050151:Subcutaneous Fat / Q000000981:diagnostic imaging*; D014463:Ultrasonography; D055815:Young Adult
keywords: Adults; Body composition; Body fat; Ultrasound