title: Relationship between fractional exhaled nitric oxide and nasal nitric oxide in airways disease.
abstract: BACKGROUND
  Invasive techniques show evidence of a unified allergic airway. Nitric oxide is measured noninvasively from the lungs (fractional exhaled nitric oxide [FeNO]) and nose (nasal nitric oxide [nNO]).
  
  
  OBJECTIVE
  To investigate the relationship between FeNO and nNO in different airway conditions.
  
  
  METHODS
  A total of 227 participants were assessed: 41 healthy volunteers (HVs), 33 patients with asthma, 52 patients with allergic rhinitis (AR), 63 with unified airway disease (UAD), and 38 with nasal polyposis (NP). Correlation and multiple linear regression analyses were performed.
  
  
  RESULTS
  Geometric means (95% confidence intervals) for FeNO were as follows: 14.7 (12.4-17.5) ppb for HVs, 29.0 (22.5-37.4) ppb for asthma patients, 23.1 (19.0-28.1) for AR patients, 27.2 (23.0-32.4) for UAD patients, and 28.5 (21.5-37.8) for NP patients. For nNO, the values were as follows: 878.1 (807.0-955.6) ppb for HVs, 674.1 (557.4-815.1) for asthma patients, 853.3 (778.8-934.8) ppb for AR patients, 763.4 (694.1-839.5) for UAD patients, and 388.6 (317.9-474.9) for NP patients. The nNO was lower in the NP group than the other groups (P < .001). The nNO and FeNO were correlated in the AR patients (r = 0.56; P < .0001) and HVs (r = 0.44; P = .004) but not significantly in the other groups. Multiple linear regression of the whole cohort demonstrated that after diagnosis, age, sex, and inhaled corticosteroids were taken into account nNO had a significant association with FeNO (P = .02).
  
  
  CONCLUSIONS
  Reduced nNO in NP patients is due to ostiomeatal complex obstruction. FeNO is sensitive to suppression by inhaled corticosteroids. The AR and HV groups have no such confounders; hence, correlation is most evident. Exclusion of confounders reveals a correlation between upper and lower airway inflammation with noninvasive techniques.
authors.affiliation: Asthma & Allergy Research Group, University of Dundee, Dundee, Scotland.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Williamson
authors.forename: Sriram
authors.initials: S
authors.lastname: Vaidyanathan
authors.forename: Karine
authors.initials: K
authors.lastname: Clearie
authors.forename: Munro
authors.initials: M
authors.lastname: Stewart
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Lipworth
mesh_terms: D000305:Adrenal Cortex Hormones / Q000737:chemistry / Q000627:therapeutic use; D000328:Adult; D001249:Asthma / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology; D001944:Breath Tests / Q000379:methods; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D009296:Nasal Cavity / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D015508:Nasal Obstruction / Q000378:metabolism; D009298:Nasal Polyps; D009569:Nitric Oxide / Q000737:chemistry / Q000378:metabolism*; D012107:Research Design; D012221:Rhinitis, Allergic, Perennial / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology
chemical_list: D000305:Adrenal Cortex Hormones; D009569:Nitric Oxide