Relation of occupational exposure to respiratory symptoms and asthma in a general population sample: Self-reported versus interview-based exposure data

The objective of this study was to examine how the consistency of self-reported exposure to dust or gas, asbestos, and quartz varied between subjects with and those without respiratory symptoms and asthma in a Norwegian community sample (n=714) in 1987-1988. Exposure characterization obtained in a structured work history interview was used as the "gold standard" The authors also wanted to assess how the exposure-disease relation differed when the exposure was based on self-reported versus interview-obtained data. The prevalence of self-reported exposure to dust or gas, asbestos, and quartz was 28%, 5%, and 4%, respectively. The sensitivity of the self-reported exposure data varied from 21% to 64% and was higher in those with than in those without the respiratory disorders. The specificity varied from 78% to 100% and was lower in those with than in those without the respiratory disorders. The sex-, age-, and smoking-adjusted odds ratios of the respiratory disorders in those with exposure to dust or gas and to asbestos were only slightly reduced when misclassification was taken into account. The corresponding numbers for exposure to quartz were halved and lost their statistical significance when the misclassification was allowed for. In this general population sample, the self-reported occupational, airborne exposure data were differentially misclassified by disease status.