Work-related Symptoms and Asthma among Fish Processing Workers

After observing several clinical patients with respiratory symptoms, we initiated a questionnaire survey to assess prevalence of and predictors for asthma and work-related symptoms among workers in fish processing plants. A questionnaire with items on work conditions, work-related symptoms, and respiratory symptoms/diseases was sent to 916 fish processing workers, the 1836 licenced fishermen in Sweden, and 1965 controls; of those, 43%, 57%, and 53%, respectively, responded. Risks, hazard ratios (HRs), and prevalence ratios (PRs) were calculated with Cox regression, and 95% confidence intervals (CIs) were computed. The risk of asthma among fish filleting workers was increased during the years working in the fish processing industry when compared to the other fish processing workers and controls (HR 3.6, 95% CI 1.6-8.1, adjusted for atopy, gender, and ever smoking). The filleters had an increased PR for most of the work-related respiratory symptoms investigated. All fish processing workers had a higher PR for flu-like symptoms. Use of a pressure sprayer was identified as a risk for asthma and respiratory symptoms among both fish processing workers and controls. Filleters had changed work tasks because of respiratory symptoms more often (Fisher's exact test, p = 0.02) than other fish processing workers. In conclusion the fish filleters and pressure sprayer users reported more adult asthma and cough with phlegm compared to the other fish processing workers and controls. The use of pressure sprayers must be reduced and machinery should be completely encased to reduce workers' exposure to bioaerosols and its effects on the respiratory tract.