title: Differences in nasal irritant sensitivity by age, gender, and allergic rhinitis status.
abstract: OBJECTIVE
  Sensory (eye, nose, and throat) irritation is an important component of non-specific building-related illness ("sick-building syndrome"). Inter-individual variability in susceptibility to upper airway/mucous membrane irritants is suspected epidemiologically, but has been neglected experimentally. We wished to document population variability in nasal irritant sensitivity, as indexed by threshold measurements of sensory acuity. We hypothesized that younger subjects, women, and allergic rhinitis sufferers would display lower sensory thresholds than would older subjects, men, and rhinitis non-sufferers.
  
  
  METHODS
  We evaluated Sixty human subjects (stratified by age, gender, and seasonal allergy status), using two different test systems: (1) carbon dioxide (detection) and (2) n-propanol (localization). We obtained carbon dioxide (CO2) detection thresholds using an ascending concentration series, presenting 3-s pulses of CO2, paired with air in random order, by nasal cannula. Localization thresholds were obtained by the simultaneous presentation of n-propanol vapor (ascending concentrations in air) and blanks (saturated water vapor in air) to opposite nostrils, with laterality randomized. Threshold data were log-transformed to satisfy normality and analyzed by population marker via ANOVA and linear regression.
  
  
  RESULTS
  Test-retest variability was greater for volatile organic compound (VOC) localization than for CO2 detection (r=0.50 and 0.75, respectively); the two measurements were, however, positively correlated (r=0.48; P<0.001). Age predicted both (log-transformed) VOC localization thresholds (P<0.0001) and (log-transformed) CO2 thresholds (P<0.01), with younger age predicting lower thresholds. Female gender predicted lower CO2 detection (P<0.05) but not VOC localization thresholds (P=0.10). Nasal allergies predicted lower VOC localization (P<0.05) but not CO2 detection thresholds (P=0.52).
  
  
  CONCLUSIONS
  Consistent with epidemiological reporting patterns in so-called problem buildings, nasal irritant sensitivity appears to be non-randomly distributed in the population, with significant variability predicted by age, gender, and the presence of allergic rhinitis.
authors.affiliation: Upper Airway Biology Laboratory, University of California, San Francisco, 1301 South 46th Street, Building 112, Richmond, California 94804, USA. dennis@itsa.ucsf.edu
authors.forename: Dennis
authors.initials: D
authors.lastname: Shusterman
authors.forename: Mary Alice
authors.initials: MA
authors.lastname: Murphy
authors.forename: John
authors.initials: J
authors.lastname: Balmes
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D002245:Carbon Dioxide; D005260:Female; D006801:Humans; D007509:Irritants / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D009296:Nasal Cavity / Q000473:pathology*; D012221:Rhinitis, Allergic, Perennial / Q000150:complications*; D012307:Risk Factors; D012684:Sensory Thresholds; D012737:Sex Factors; D018877:Sick Building Syndrome / Q000503:physiopathology*
chemical_list: D007509:Irritants; D002245:Carbon Dioxide