Objective: To study the effect of occupational exposure on the incidence of adult asthma and six respiratory symptoms using a job exposure matrix (JEM).
Methods: From 1985, we conducted an 11-year community cohort study on the incidence of asthma and respiratory symptoms in Western Norway (N=2401, aged 15-70 years at baseline). The analyses in the current study were based on subjects < or =65 years at baseline, since those >65 years were unlikely to experience significant occupational exposures within the follow-up period.
Results: More women than men were exposed to biological dust (38% versus 29%), while more men were exposed to mineral dust (48% versus 19%), and gas or fumes (58% versus 53%). After adjusting for age, educational level, smoking, and previous occupational exposures, we found that high exposure to biological dust exposure was significantly related to a higher incidence of chronic and morning cough in men; for women, low exposure was related to attacks of dyspnea. Low exposure to workplace gas or fumes was significantly related to incident phlegm cough and attacks of dyspnea for women, while for men, high exposure was related to dyspnea grade 2. For the incidence of asthma and phlegm cough, after adjusting for all confounders, we found a significant interaction between workplace exposures and gender, where women had a higher risk of disease.
Conclusions: Assessed by a JEM, occupational airborne exposure was weakly related to the incidence of asthma and respiratory symptoms, significantly more so for women than for men.