The risk of asthma in relation to occupational exposures: a case-control study from a Swedish city

The purpose of this study was to estimate the risk of adult asthma in relat ion to certain occupational exposures. The study was designed as a case-control study in Goteborg, including 321 s ubjects with asthma, born between 1926 and 1970, Controls (n=1,459) were ra ndomly selected Univel from the same area from registers of the 1986 popula tion. Questionnaire information was collected in 1996, and included occupat ional exposures and smoking habits. Odds ratios were calculated for exposur e before asthma onset, stratified by sex and age-class, The highest risks for asthma were associated with exposure to grain dust (o dds ratio (OR) 4.2, 95% confidence interval (CI) 1.6-10.7) and flour dust ( OR 2.8, 95% CI 1.1-7.2). Among males, significantly increased risks were ob served after exposure to flour questionnaires dust, welding fumes, man-made mineral fibres, and solvents. Among females, increased risks for asthma we re associated,vith exposures to paper dust and textile dust. welding In log istic regression models controlling for age, smoking, sex and interacting e xposures, increased risks were seen for welding fumes (OR 2.0, 95% CI 15-3. 4), manmade mineral fibres (OR 2.6, 95% CI 1.4-7.3) and solvents (OR 2.2, 9 5% CI 1.2-3.2). The fraction of asthma attributed to occupational exposures after adjusting for sex, smoking and age was 11% (95% CI 7-14%), In conclusion, exposure to welding fumes, man-made mineral fibres, solvents and textile dust is associated with increased risk for asthma.