title: Obesity and bronchial obstruction in impulse oscillometry at age 5-7 years in a prospective post-bronchiolitis cohort.
abstract: OBJECTIVE
  Obesity has been linked with asthma symptoms, need for asthma treatment and reduced lung function but not with increased bronchial reactivity in children. The aim of this study was to evaluate the association between previous or current weight status and current lung function and bronchial reactivity to exercise at early school age.
  
  
  METHODS
  Ninety-nine children hospitalized for bronchiolitis at the age of less than 6 months were studied with impulse oscillometry (IOS) at the mean age of 6.3 years. Data on birth weight and weight gain in infancy before hospitalization were collected during hospitalization. Current weight and height data were transformed into age- and sex-specific height-related body mass index z scores (zBMI) using the Finnish national population-based weight and height data as reference.
  
  
  RESULTS
  Some significant though only low or modest correlations were found between current zBMI and baseline, post-exercise and post-bronchodilator IOS values in adjusted linear regression analysis. Seven obese children by zBMI had higher post-bronchodilator airway impedance (Zrs) and resistance (Rrs) at 5 Hz and lower post-bronchodilator frequency dependency of resistance (dRrs/df) than normal weight children. There were no significant differences in responses to exercise or to bronchodilators between currently obese or overweight children and normal weight children. Birth weight less than 3,000 g was associated with larger exercise-induced changes in Zrs and Rrs at 5 Hz, and in reactance (Xrs) at 5 Hz, than those with birth weight more than 3,000 g.
  
  
  CONCLUSIONS
  Preliminary evidence was found that obesity may be associated with airway obstruction, but not with bronchial hyper-reactivity.
authors.affiliation: Tampere Center for Child Health Research, Tampere University and University Hospital, Tampere, Finland.
authors.forename: Eero
authors.initials: E
authors.lastname: Lauhkonen
authors.affiliation: Tampere Center for Child Health Research, Tampere University and University Hospital, Tampere, Finland.
authors.forename: Petri
authors.initials: P
authors.lastname: Koponen
authors.affiliation: Seinäjoki Central Hospital, Seinäjoki, Finland.
authors.forename: Kirsi
authors.initials: K
authors.lastname: Nuolivirta
authors.affiliation: Allergy Centre, Tampere University Hospital, Tampere, Finland.
authors.forename: Marita
authors.initials: M
authors.lastname: Paassilta
authors.affiliation: Department of Clinical Physiology, Tampere University Hospital, Tampere, Finland.|Department of Clinical Physiology, Turku University Hospital, Turku, Finland.
authors.forename: Jyri
authors.initials: J
authors.lastname: Toikka
authors.affiliation: Kuopio University Hospital, Kuopio, Finland.
authors.forename: Antti
authors.initials: A
authors.lastname: Saari
authors.affiliation: Tampere Center for Child Health Research, Tampere University and University Hospital, Tampere, Finland.
authors.forename: Matti
authors.initials: M
authors.lastname: Korppi
mesh_terms: D000402:Airway Obstruction / Q000503:physiopathology*; D000403:Airway Resistance / Q000502:physiology; D001724:Birth Weight / Q000502:physiology; D001988:Bronchiolitis / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D015444:Exercise / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009765:Obesity / Q000503:physiopathology*; D009991:Oscillometry
keywords: asthma and early wheeze; impulse oscillometry; obesity; pulmonary function testing