Occupational airborne exposure and the incidence of respiratory symptoms and asthma.

Several prevalence studies have suggested an association between occupational exposure and respiratory symptoms and asthma, but there has been a lack of incidence studies to verify this. This study examined the incidence of respiratory symptoms and asthma in an 11-year Norwegian community cohort study with 2,819 subjects. Predictors examined were sex, age, educational level, lifetime exposure to quartz, asbestos, and dust or fumes, as well as smoking habits and pack-years. The prevalence of exposure to quartz, asbestos, and dust or fumes was, respectively, 3.7%, 5.0%, and 28.3% at baseline. In those exposed to dust or fumes, the odds ratios (95% confidence intervals) varied between 1.4 (1.1, 1.7) and 2.1 (1.3, 3.2) for developing respiratory symptoms or asthma after adjusting for sex, age, educational level, and smoking. Between 5.7% and 19.3% of the incidence of respiratory symptoms and 14.4% of the incidence of asthma were attributable to dust or fumes exposure after adjustment for sex, age, educational level, and smoking. In conclusion, airborne occupational exposure increases the incidence of respiratory symptoms and asthma, independent of sex, age, educational level, smoking habits, and pack-years.