title: Low eosinophils during bronchiolitis in infancy are associated with lower risk of adulthood asthma.
abstract: BACKGROUND
  Infant bronchiolitis may be the first manifestation of asthma.
  
  
  OBJECTIVE
  To evaluate the association of early-childhood risk or protective factors for asthma and lung function reduction in adults 30 years after bronchiolitis in infancy.
  
  
  METHODS
  Forty-seven former bronchiolitis patients attended the clinical study at the median age of 29.5 years, including doctoral examination and measurement of post-bronchodilator lung function with flow-volume spirometry. Data on early-life risk factors including blood eosinophil counts on admission for bronchiolitis and on convalescence 4-6 weeks after bronchiolitis were available.
  
  
  RESULTS
  Low blood eosinophil count <0.25 × 10E9/l on admission for bronchiolitis was a significant protective factor and high blood eosinophil count >0.45 × 10E9/l on convalescence was a significant risk factor for asthma in adulthood independently from atopic status in infancy. Parental asthma and high blood eosinophil count >0.45 × 10E9/l during bronchiolitis were significant risk factors for irreversible airway obstruction (FEV1/FVC ratio below the 5th percentile lower limit of normality after bronchodilation).
  
  
  CONCLUSIONS
  Our adjusted analyses confirmed that eosinopenia during infant bronchiolitis predicted low asthma risk and eosinophilia outside infection predicted high asthma risk up to the age of 28-31 years. Parental asthma and eosinophilia during bronchiolitis were recognized as risk factors for irreversible airway obstruction.
authors.affiliation: Department of Pediatrics, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Katri
authors.initials: K
authors.lastname: Backman
authors.affiliation: Seinäjoki Central Hospital, Seinäjoki, Finland.
authors.forename: Kirsi
authors.initials: K
authors.lastname: Nuolivirta
authors.affiliation: University of Eastern Finland, Kuopio, Finland.
authors.forename: Hertta
authors.initials: H
authors.lastname: Ollikainen
authors.affiliation: Center for Child Research, Tampere University and University Hospital, Tampere, Finland.
authors.forename: Matti
authors.initials: M
authors.lastname: Korppi
authors.affiliation: Department of Pediatrics, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Eija
authors.initials: E
authors.lastname: Piippo-Savolainen
mesh_terms: D000328:Adult; D001249:Asthma / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D015415:Biomarkers / Q000097:blood; D001988:Bronchiolitis / Q000097:blood / Q000150:complications*; D004804:Eosinophils / Q000378:metabolism*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007958:Leukocyte Count; D008297:Male; D011446:Prospective Studies; D012129:Respiratory Function Tests; D012307:Risk Factors
chemical_list: D015415:Biomarkers
keywords: asthma; bronchiolitis; eosinophils; respiratory syncytial virus