title: Sex-related differences in pulmonary physiologic outcome measures in a high-risk birth cohort.
abstract: BACKGROUND
  Sex influences the risk of wheezing illnesses and the prevalence of asthma throughout childhood.
  
  
  OBJECTIVE
  To better understand the mechanisms of these effects, we analyzed longitudinal relationships between sex, lung physiology, and asthma in the Childhood Origins of ASThma birth cohort study.
  
  
  METHODS
  Childhood Origins of ASThma birth cohort study children were followed prospectively from birth and assessed annually. Results of spirometry, fractional exhaled nitric oxide (Feno), mannitol provocation testing, and (3)He gas magnetic resonance imaging were assessed by sex using multivariate models including age, asthma diagnosis, and wheezing histories.
  
  
  RESULTS
  Girls had higher prebronchodilator forced expiratory volume in 0.5 seconds/forced vital capacity values than did boys (mean difference, 0.017; 95% CI, 0.000-0.034; P = .05) of equivalent age. Postbronchodilator findings were more pronounced, with boys demonstrating reduced forced expiratory volume in 0.5 seconds/forced vital capacity values than did girls of equivalent age (mean difference, 0.032; 95% CI, 0.014-0.049; P = .0005). Conversely, girls were noted to have higher ventilation defects on (3)He magnetic resonance imaging than did boys (P = .01). No differences were noted in the rate of positive responses to mannitol provocation or Feno measurements.
  
  
  CONCLUSIONS
  Lower airflow values are present by spirometry for prepubertal boys than for age-matched girls; however, greater (3)He ventilation defects were noted in girls. This could represent a greater degree of subclinical air trapping in prepubertal girls because residual volumes are not detected on standard spirometric readings. No differences were noted between the 2 sexes with airway hyperresponsiveness (mannitol provocation testing) or inflammation (Feno). Prospective peripubertal follow-up will determine whether these differences persist or change with the de novo expression and remission of asthma based on sex and age.
authors: Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wis.
authors: Amy O
authors: AO
authors: Thomas
authors: Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wis. Electronic address: djj@medicine.wisc.edu.
authors: Daniel J
authors: DJ
authors: Jackson
authors: Department of Biostatistics and Medical Informatics, University of Wisconsin School of Medicine and Public Health, Madison, Wis.
authors: Michael D
authors: MD
authors: Evans
authors: Department of Biostatistics and Medical Informatics, University of Wisconsin School of Medicine and Public Health, Madison, Wis.
authors: Victoria
authors: V
authors: Rajamanickam
authors: Department of Biostatistics and Medical Informatics, University of Wisconsin School of Medicine and Public Health, Madison, Wis.
authors: Ronald E
authors: RE
authors: Gangnon
authors: Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wis; Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, Wis.
authors: Sean B
authors: SB
authors: Fain
authors: Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wis; Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wis; Department of Pharmacy, University of Wisconsin School of Medicine and Public Health, Madison, Wis.
authors: Ronald L
authors: RL
authors: Sorkness
authors: Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wis.
authors: Adesua Y
authors: AY
authors: Okupa
authors: Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wis.
authors: Alex
authors: A
authors: Thomas
authors: Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wis; Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wis.
authors: James E
authors: JE
authors: Gern
authors: Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wis; Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wis.
authors: Robert F
authors: RF
authors: Lemanske
mesh_terms: D000328:Adult; D001249:Asthma / Q000175:diagnosis* / Q000276:immunology / Q000503:physiopathology; D001985:Bronchial Provocation Tests; D002648:Child; D002675:Child, Preschool; D045853:Exhalation; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D007223:Infant; D008168:Lung / Q000276:immunology / Q000503:physiopathology; D008297:Male; D008353:Mannitol / Q000008:administration & dosage / Q000276:immunology; D015999:Multivariate Analysis; D009569:Nitric Oxide / Q000378:metabolism; D011446:Prospective Studies; D012135:Respiratory Sounds / Q000175:diagnosis* / Q000276:immunology / Q000503:physiopathology; D012307:Risk Factors; D012737:Sex Factors; D013147:Spirometry; D014797:Vital Capacity
chemical_list: D009569:Nitric Oxide; D008353:Mannitol
keywords: Sex; airway hyperreactivity; asthma; fractional exhaled nitric oxide; gender; helium MRI; mannitol; pulmonary physiology; spirometry; ventilation defects