title: Determinants of asthma after severe respiratory syncytial virus bronchiolitis.
abstract: BACKGROUND
  The development of asthma after respiratory syncytial virus (RSV) bronchiolitis has been demonstrated in case-control studies, although the determinants of post-RSV asthma remain undefined.
  
  
  OBJECTIVE
  We sought to evaluate the potential determinants of physician-diagnosed asthma after severe RSV bronchiolitis during infancy.
  
  
  METHODS
  We enrolled 206 children during an initial episode of severe RSV bronchiolitis at 12 months of age or less in a prospective cohort study and followed these children for up to 6 years. In a subset of 81 children, we analyzed CCL5 (RANTES) mRNA expression in upper airway epithelial cells.
  
  
  RESULTS
  Forty-eight percent of children had physician-diagnosed asthma before the seventh birthday. Independent determinants significantly associated with increased risk for physician-diagnosed asthma by the seventh birthday included maternal asthma (odds ratio [OR], 5.2; 95% CI, 1.7-15.9; P = .004), exposure to high levels of dog allergen (OR, 3.2; 95% CI, 1.3-7.7; P = .012), aeroallergen sensitivity at age 3 years (OR, 10.7; 95% CI, 2.1-55.0; P = .005), recurrent wheezing during the first 3 years of life (OR, 7.3; 95% CI, 1.2-43.3; P = .028), and CCL5 expression in nasal epithelia during acute RSV infection (OR, 3.8; 95% CI, 1.2-2.4; P < .001). White children (OR, 0.19; 95% CI, 0.04-0.93; P = .041) and children attending day care (OR, 0.18; 95% CI, 0.04-0.84; P = .029) had a decreased risk of physician-diagnosed asthma.
  
  
  CONCLUSIONS
  Approximately 50% of children who experience severe RSV bronchiolitis have a subsequent asthma diagnosis. The presence of increased CCL5 levels in nasal epithelia at the time of bronchiolitis or the development of allergic sensitization by age 3 years are associated with increased likelihood of subsequent asthma.
authors.affiliation: Division of Pediatric Allergy, Immunology and Pulmonary Medicine, Department of Pediatrics, Washington University School of Medicine, St Louis, MO 63110-1093, USA.
authors.forename: Leonard B
authors.initials: LB
authors.lastname: Bacharier
authors.forename: Rebecca
authors.initials: R
authors.lastname: Cohen
authors.forename: Toni
authors.initials: T
authors.lastname: Schweiger
authors.forename: Huiquing
authors.initials: H
authors.lastname: Yin-Declue
authors.forename: Chandrika
authors.initials: C
authors.lastname: Christie
authors.forename: Jie
authors.initials: J
authors.lastname: Zheng
authors.forename: Kenneth B
authors.initials: KB
authors.lastname: Schechtman
authors.forename: Robert C
authors.initials: RC
authors.lastname: Strunk
authors.forename: Mario
authors.initials: M
authors.lastname: Castro
mesh_terms: D000485:Allergens / Q000276:immunology; D000818:Animals; D001249:Asthma / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology*; D001990:Bronchiolitis, Viral / Q000150:complications* / Q000453:epidemiology / Q000503:physiopathology / Q000821:virology; D018946:Chemokine CCL5 / Q000235:genetics / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004285:Dogs; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009296:Nasal Cavity / Q000166:cytology; D015995:Prevalence; D011446:Prospective Studies; D018357:Respiratory Syncytial Virus Infections / Q000150:complications* / Q000453:epidemiology / Q000503:physiopathology / Q000821:virology; D018113:Respiratory Syncytial Virus, Human / Q000472:pathogenicity; D012307:Risk Factors; D012720:Severity of Illness Index
chemical_list: D000485:Allergens; C483024:CCL5 protein, human; D018946:Chemokine CCL5