title: Performance of self-reported occupational exposure compared to a job-exposure matrix approach in asthma and chronic rhinitis.
abstract: OBJECTIVE
  Self-reported exposure to vapours, gas, dust or fumes (VGDF) has been widely used as an occupational exposure metric in epidemiological studies of chronic lung diseases. Our objective was to characterise the performance of VGDF for repeatability, systematic misclassification, and sensitivity and specificity against exposure likelihood by a job-exposure matrix (JEM).
  
  
  METHODS
  We analysed data from two interviews, 24 months apart, of adults with asthma and chronic rhinitis. Using distinct job as the unit of analysis, we tested a single response item (exposure to VGDF) against assignment using a JEM. We further analysed VGDF and the JEM among a subset of 199 subjects who reported the same job at both interviews, using logistic regression analysis to test factors associated with VGDF inconsistency and discordance with the JEM.
  
  
  RESULTS
  VGDF was reported for 193 (44%) of 436 distinct jobs held by the 348 subjects studied; moderate to high exposure likelihood by JEM was assigned to 120 jobs (28%). The sensitivity and specificity of VGDF against JEM were 71% and 66%, respectively. Among 199 subjects with the same job at both interviews, 32% had a discordant VGDF status (kappa = 0.35). Those with chronic rhinitis without concomitant asthma compared to asthma alone were more likely to have a VGDF report discordant with the JEM (OR 3.6, 95% CI 1.4 to 9.0; p = 0.01). Rhinitis was also associated with reported VGDF in a job classified by the JEM as low exposure (OR 3.9, 95% CI 1.6 to 9.4; p = 0.003).
  
  
  CONCLUSIONS
  The VGDF item is moderately sensitive measured against JEM as a benchmark. The measure is a useful assessment method for epidemiological studies of occupational exposure risk.
authors.affiliation: Division of Occupational and Environmental Medicine, University of California San Francisco, 1001 Potrero Avenue, San Francisco, CA 94110, USA. pquinlan@medsfgh.ucsf.edu
authors.forename: P J
authors.initials: PJ
authors.lastname: Quinlan
authors.forename: G
authors.initials: G
authors.lastname: Earnest
authors.forename: M D
authors.initials: MD
authors.lastname: Eisner
authors.forename: E H
authors.initials: EH
authors.lastname: Yelin
authors.forename: P P
authors.initials: PP
authors.lastname: Katz
authors.forename: J R
authors.initials: JR
authors.lastname: Balmes
authors.forename: P D
authors.initials: PD
authors.lastname: Blanc
mesh_terms: D000328:Adult; D000395:Air Pollutants, Occupational / Q000032:analysis / Q000633:toxicity*; D001249:Asthma / Q000209:etiology*; D003627:Data Interpretation, Statistical; D004391:Dust; D005740:Gases; D006801:Humans; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000209:etiology*; D016273:Occupational Exposure / Q000032:analysis; D016272:Occupational Health; D009790:Occupations; D012220:Rhinitis / Q000209:etiology*; D018570:Risk Assessment / Q000379:methods; D012650:Self Disclosure; D012680:Sensitivity and Specificity
chemical_list: D000395:Air Pollutants, Occupational; D004391:Dust; D005740:Gases