title: Validity of new child-specific thoracic gas volume prediction equations for air-displacement plethysmography.
abstract: BACKGROUND
  To determine the validity of the recently developed child-specific thoracic gas volume (TGV) prediction equations for use in air-displacement plethysmography (ADP) in diverse pediatric populations.
  
  
  METHODS
  Three distinct populations were studied: European American and African American children living in Birmingham, Alabama and European children living in Lisbon, Portugal. Each child completed a standard ADP testing protocol, including a measured TGV according to the manufactures software criteria. Measured TGV was compared to the predicted TGV from current adult-based ADP proprietary equations and to the recently developed child-specific TGV equations of Fields et al. Similarly, percent body fat, derived using the TGV prediction equations, was compared to percent body fat derived using measured TGV.
  
  
  RESULTS
  Predicted TGV from adult-based equations was significantly different from measured TGV in girls from each of the three ethnic groups (P < 0.05), however child-specific TGV estimates did not significantly differ from measured TGV in any of the ethnic or gender groups. Percent body fat estimates using adult-derived and child-specific TGV estimates did not differ significantly from percent body fat measures using measured TGV in any of the groups.
  
  
  CONCLUSIONS
  The child-specific TGV equations developed by Fields et al. provided a modest improvement over the adult-based TGV equations in an ethnically diverse group of children.
authors.affiliation: Department of Nutrition Sciences, University of Alabama at Birmingham, AL, USA. higginsp@uab.edu
authors.forename: Paul B
authors.initials: PB
authors.lastname: Higgins
authors.forename: Analiza M
authors.initials: AM
authors.lastname: Silva
authors.forename: Luis B
authors.initials: LB
authors.lastname: Sardinha
authors.forename: Holly R
authors.initials: HR
authors.lastname: Hull
authors.forename: Michael I
authors.initials: MI
authors.lastname: Goran
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Gower
authors.forename: David A
authors.initials: DA
authors.lastname: Fields
mesh_terms: D001741:Black or African American; D000407:Alabama; D001823:Body Composition; D001827:Body Height / Q000208:ethnology; D015992:Body Mass Index; D001835:Body Weight / Q000208:ethnology; D002648:Child; D005260:Female; D005652:Functional Residual Capacity; D006801:Humans; D008176:Lung Volume Measurements / Q000379:methods*; D008297:Male; D010991:Plethysmography / Q000295:instrumentation / Q000379:methods*; D011174:Portugal; D015203:Reproducibility of Results; D044465:White People