title: Body composition and respiratory function in healthy non-obese children.
abstract: BACKGROUND
  The purpose of the present paper was to evaluate the role that body composition plays in lung function, among healthy children and adolescents.
  
  
  METHODS
  Cross-sectional study was undertaken using sex- and age-stratified sampling among healthy children and adolescents aged 6-18 years. Spirometry was performed on every child who fulfilled inclusion criteria. Fat mass (FM) and fat-free mass (FFM) were calculated from triceps skinfold thickness and arm circumference. Multiple logistic regression was used to obtain adjusted prevalence odds ratios (OR) and 95% confidence intervals (95%CI) between low pulmonary function (PF) of schoolchildren and body composition expressed in FM and FFM. Calculations of OR imply that the outcome is dichotomous (low PF/normal PF), therefore those children who had parameters of pulmonary function below the 25th percentile were classed as cases and the rest of the subjects were considered as controls.
  
  
  RESULTS
  A total of 2408 children were included; 1270 (53%) of them were male and 1138 (47%), female. Among boys the increase of FFM was associated with an increase of forced expiratory volume in 1 s (FEV1). Among girls the increase of FFM was associated with an increase of FEV1, forced vital capacity, and peak expiratory flow. The increase in FM was associated with a decrease of spirometric parameters in both genders, with a stronger effect among boys.
  
  
  CONCLUSIONS
  The present study confirms the negative effect of body fat on the PF of children and adolescents, even though obese subjects were excluded. The effect is different between boys and girls.
authors.affiliation: Division of Respiratory Medicine, Clinic University Hospital, University of Santiago De Compostela, Santiago de Compostela, Spain. fjgbarcala@telefonica.net
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Gonzalez-Barcala
authors.forename: Bahi
authors.initials: B
authors.lastname: Takkouche
authors.forename: Luis
authors.initials: L
authors.lastname: Valdes
authors.forename: Rosaura
authors.initials: R
authors.lastname: Leis
authors.forename: Pedro
authors.initials: P
authors.lastname: Alvarez-Calderon
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Cabanas
authors.forename: Jose R
authors.initials: JR
authors.lastname: Rodríguez Suarez
authors.forename: Rafael
authors.initials: R
authors.lastname: Tojo
mesh_terms: D000293:Adolescent; D001823:Body Composition; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D012016:Reference Values; D012119:Respiration