Article Text
Abstract
Objectives: Four diacetyl workers were found to have bronchiolitis obliterans syndrome. The aim of this study was to investigate exposures, respiratory symptoms, lung function and exposure-response relationships.
Methods: The study was conducted among 175 of a cohort of 196 workers from a plant which produced diacetyl between 1960 and 2003. All available historical exposure data were used to model diacetyl exposure. Lung function and questionnaire data on respiratory symptoms were compared to a general population sample and respiratory symptoms to an internal reference group.
Results: Workers were potentially exposed to acetoin, diacetyl, acetaldehyde, and acetic acid. Historic diacetyl exposure in the working environments ranged from 1.8 to 351 mg/m3 and for specific tasks from 3 to 396 mg/m3. Diacetyl workers reported significantly more respiratory symptoms compared to the general population sample (continuous trouble with breathing prevalence ratio (PR=2.6; 95% CI 1.3-5.1); daily cough (PR=1.5; 95% CI 1.1-2.1); asthma attack (ever) (PR=2.0; 95% CI 1.2-3.4); doctor diagnosed asthma (PR=2.2; 95% CI 1.3-3.8); asthma attack in the last year (PR=4.7; 95% CI 1.9-11.4)). Lung function did not differ between the groups. A positive relationship between exposure and FEV1 was found. Operators reported significantly more respiratory symptoms compared to a minimally exposed internal reference group (ever trouble with breathing prevalence ratio (PR=2.8; 95% CI 1.1-7.0); work-related shortness of breath in the last year (PR=7.5; 95% CI 1.1-52.9)).
Conclusion: The excess of respiratory symptoms in this retrospective cohort supports the occupational hazard in diacetyl production demonstrated earlier in the case cluster. A job title-related excess of symptoms existed in operators with the highest exposures compared to an internal reference population. Limited historical exposure data did not support a quantitative individual diacetyl exposure-response relation, but our findings suggest that preventive measures are prudent.