Incidence of asthma among workers exposed to sulphur dioxide and other irritant gases

Abstract

The aim of the present study was to investigate whether repeated peak exposure (gassings) to sulphur dioxide (SO 2 ) and other irritant gases increases the risk of new-onset asthma. A questionnaire was sent to 4,112 sulphite workers, of whom 1,919 completed the questionnaire and 396 completed the short-form questionnaire, which was sent out as a last reminder. A sample of 130 nonrespondents completed a telephone interview using the short-form questionnaire.The incidence of adult-onset, physician-diagnosed asthma during employment duration was analysed in relation to exposure to SO 2 and gassings giving rise to respiratory symptoms. Incidence rates, as well as incidence rate ratios with 95% confidence interval (CI), were calculated. Further Cox regression models were used allowing assessment of hazard ratios (HR) stratified for sex and adjusted for atopy, smoking habits and age.The incidence rate for asthma among sulphite mill workers reporting gassings of SO 2 was 6.2 out of 1,000 person-yrs, compared with 1.9 out of 1,000 person-yrs among subjects unexposed to SO 2 and any gassings (HR (95% CI) 4.0 (2.1-7.7)). Among males reporting gassings to SO 2 , the HR (95% CI) for asthma was 5.8 (2.6-13) compared with unexposed males.In conclusion, repeated peak exposure to sulphur dioxide increased the incidence of asthma during work in sulphite pulp mills, which supports the hypothesis of irritant-induced asthma.

Cohort mortality study of Swedish pulp and paper mill workers—nonmalignant diseases

“…There was no generally increased mortality from nonmalignant respiratory diseases found in this study, even if we know that, in mills 5-8, there was an increased incidence of asthma (15) and chronic bronchitis among the workers exposed to irritant gases. In the IARC pulp and paper mill study of mortality among workers exposed to sulfur dioxide, there was no increased risk from bronchitis, emphysema, and asthma, when analyzed together (7).…”

“…Mills 1-3 were included in the IARC pulp and paper cohort study (8,13,14). With regard to asthma and exposure to sulfur dioxide, results from a questionnaire study for mills 5-8 have also been published earlier (15).…”

EAACI position paper: irritant‐induced asthma

“…Irritant-induced asthma has been documented after repeated high-level exposures (i.e. 'puffs' or 'gassings') to irritants substances, mainly chlorine, SO 2 , and ozone (Table 4) (10,(30)(31)(32)(33)(34). The causal relationship of this form of IIA occurring with a less acute-onset in a context of multiple high-level exposures can be supported by the documentation of repeated symptomatic inhalation accidents requiring medical care or reports to first aid units or occupational health services.…”

“…Longitudinal workforce-based epidemiological studies have provided evidence that the development of asthma can result from multiple high-level exposures (Table 5) (10,(30)(31)(32)(33)(34). Repeated high-level exposures ('gassings' or 'puffs') to chlorine in metal production workers (32) and ozone or sulfur dioxide in pulp mill workers (33,34) were shown to be associated with an increased incidence of new-onset asthma.…”

“…Repeated high-level exposures ('gassings' or 'puffs') to chlorine in metal production workers (32) and ozone or sulfur dioxide in pulp mill workers (33,34) were shown to be associated with an increased incidence of new-onset asthma.…”