Self-reported asthma and respiratory symptoms in sewage workers

To investigate whether Swedish sewage workers have an increased risk of respiratory symptoms or diseases. In a cross-sectional study, 149 sewage workers and 138 referents, selected from among other municipal workers, were given a self-administered questionnaire about asthma, atopy, smoking and symptoms from the airways, skin and eyes. Two-by-two statistics was used to compare proportions and logistic regression was used for multivariable analyses. The sewage workers reported significantly more adult asthma than the referents. The adjusted odds ratio for asthma during adulthood was 5.3 (95% confidence interval 1.1-26) as determined from a multivariable logistic regression analysis when controlling for age, gender, atopic disposition and tobacco smoking. They also had increased risk, but not statistically significant, of some possibly asthma related symptoms and chronic bronchitis. There was no difference in atopic disposition based on a history of allergic diseases in childhood or in parents. Neither were there any differences in symptoms in the eyes or skin. Self-reported asthma was more common among the sewage workers than other municipal workers. This might be caused by occupational exposure to irritant or inflammatory substances.