Work-related asthma: prevalence estimates by sex, age and smoking habits in a community sample

SETTING: Two-phased study of a general population sample in Norway. OBJECTIVE: To assess the prevalence of work-related asthma by sex, age and smoking habits. DESIGN: The first phase, a mail questionnaire on asthma to a random sample of the general population of Hordaland County, Norway gave a 90% response. A stratified sample of the responders (n = 1512) was invited to complete an occupational history questionnaire and performing spirometry and bronchial hyperresponsiveness. The attendance rate was 84%. Asthmatics were defined as having work-related asthma if they answered positively the questions: "H ave you ever had respiratory symptoms in relation to your work? Did the sym ptoms improve on absence from work?" RESULTS: The prevalence of work-related asthma was 0.9% in this population, constituting 28% of all asthmatics (95% confidence interval 25-31). The pr evalence of work-related asthma was twice as high in men as in women, and d id not differ significantly with age or between smoking groups. CONCLUSION: Work-related asthma amounts to a significant proportion of tota l asthma in this population. This should be taken into account by health pl anners as it is by definition a preventable disorder.