title: Environmental allergies and respiratory morbidities in cystic fibrosis.
abstract: BACKGROUND
  Cystic fibrosis (CF) is characterized by recurrent respiratory infections and progressive lung disease. Although environmental factors account for 50% of the variation in CF lung function, few specific exposures have been identified. Studies using small study samples focusing on environmental allergies in CF have had inconsistent results. Our objective was to examine the role of environmental allergies in upper and lower respiratory tract morbidities in CF.
  
  
  METHODS
  A total of 1,321 subjects with CF were recruited through the U.S. CF Twin-Sibling Study. Questionnaires were used to determine the presence/absence of environmental allergies. Questionnaires, chart review, and U.S. CF Foundation Patient Registry data were used to track outcomes.
  
  
  RESULTS
  Within the study sample 14% reported environmental allergies. Environmental allergies were associated with a higher risk of sinus disease (adjusted OR: 2.68; P < 0.001) and nasal polyps (adjusted OR: 1.74; P = 0.003). Environmental allergies were also associated with a more rapid decline in lung function (additional -1.1%/year; P = 0.001). However, allergies were associated with a later median age of acquisition of Pseudomonas aeruginosa (6.6 years vs. 4.4 years; log rank P = 0.027). The reported use of common allergy medications, anti-histamines and leukotriene inhibitors, did not alter the frequency of respiratory morbidities.
  
  
  CONCLUSIONS
  Environmental allergies are associated with an increased risk of sinus disease and nasal polyps and a more rapid decline in CF lung function, but may have a protective effect against the acquisition of P. aeruginosa. Prospective studies are needed to confirm these associations which have implications for more aggressive management of allergies.
authors.affiliation: Eudowood Division of Pediatric Respiratory Sciences, Johns Hopkins University, Baltimore, Maryland 21287, USA. mcollac1@jhmi.edu
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Collaco
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Morrow
authors.forename: Deanna M
authors.initials: DM
authors.lastname: Green
authors.forename: Garry R
authors.initials: GR
authors.lastname: Cutting
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Mogayzel
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003550:Cystic Fibrosis / Q000150:complications* / Q000503:physiopathology*; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D006967:Hypersensitivity / Q000150:complications* / Q000503:physiopathology*; D007223:Infant; D007231:Infant, Newborn; D008168:Lung / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011552:Pseudomonas Infections / Q000150:complications / Q000503:physiopathology; D012129:Respiratory Function Tests / Q000379:methods / Q000706:statistics & numerical data; D011795:Surveys and Questionnaires; D055815:Young Adult
keywords: FEV1; Pseudomonas aeruginosa; allergies; cystic fibrosis; lung function; nasal polyps; sinus disease