title: Nonallergic rhinitis and its association with smoking and lower airway disease: A general population study.
abstract: BACKGROUND
  The cause of nonallergic rhinitis (NAR) and its relation to lower airway disease remains unclear. The purpose of this study was to perform a descriptive analysis of the occurrence of rhinitis in a Danish general population with focus on NAR and its association with smoking and lower airway disease.
  
  
  METHODS
  A population-based, cross-sectional study conducted in Copenhagen, Denmark was performed. A random sample from the general population (n = 7931; age, 18-69 years) was invited to a general health examination including measurements of serum-specific immunoglobulin E (IgE) to common aeroallergens; 3471 (44%) persons were accepted. For further analysis, we divided the population into the following groups: (I) negative specific IgE and no rhinitis (controls); (II) negative specific IgE and rhinitis (NAR); (III) positive specific IgE and rhinitis (allergic rhinitis [AR]); and (IV) positive specific IgE but no rhinitis (sensitized).
  
  
  RESULTS
  We found that NAR was associated with asthma (odds ratio [OR] = 2.51 [1.87-3.37]); chronic bronchitis (OR = 2.27 [1.85-2.79]); current smoking (>15 g/day; OR = 1.57 [1.18-2.08]); lower forced expiratory volume in 1 second/forced vital capacity (FEV(1)/FVC) ratios and reduced FEV(1) values. The association with chronic bronchitis was stronger in NAR than in AR, whereas the opposite was true for asthma. FEV(1)/FVC of <70% was not significantly associated to any group.
  
  
  CONCLUSIONS
  This epidemiological study indicates that both asthma and chronic bronchitis are important comorbidities in NAR confirming the "united airway" hypothesis, and that smoking might be a significant modulator of disease. Although NAR was significantly associated with poor lung function, no significant association with chronic obstructive pulmonary disease was shown.
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark. kaare.haakansson@rh.regionh.dk
authors.forename: Kåre
authors.initials: K
authors.lastname: Håkansson
authors.forename: Christian
authors.initials: C
authors.lastname: von Buchwald
authors.forename: Simon F
authors.initials: SF
authors.lastname: Thomsen
authors.forename: Jacob P
authors.initials: JP
authors.lastname: Thyssen
authors.forename: Vibeke
authors.initials: V
authors.lastname: Backer
authors.forename: Allan
authors.initials: A
authors.lastname: Linneberg
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000485:Allergens / Q000009:adverse effects / Q000276:immunology; D000818:Animals; D001249:Asthma / Q000453:epidemiology*; D029662:Betula; D001991:Bronchitis / Q000453:epidemiology*; D002415:Cats; D015897:Comorbidity; D003430:Cross-Sectional Studies; D003718:Denmark; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D008297:Male; D008875:Middle Aged; D006109:Poaceae; D011058:Pollen / Q000009:adverse effects; D044382:Population Groups; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology*; D039981:Pyroglyphidae; D012129:Respiratory Function Tests; D012220:Rhinitis / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D012221:Rhinitis, Allergic, Perennial / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D006255:Rhinitis, Allergic, Seasonal / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D012907:Smoking
chemical_list: D000485:Allergens; D007073:Immunoglobulin E