Lung cancer incidence among Norwegian silicon carbide industry workers: associations with particulate exposure factors
Occupational and Environmental Medicine, 05/25/2012
Bugge MD et al. – The results indicated that crystalline silica in the form of cristobalite was the most important occupational exposure factor responsible for lung cancer excess in the Norwegian silicon carbide (SiC) industry. SiC fibres seemed to have an additional effect.Methods
- Cumulative exposure to total and respirable dust, respirable quartz, cristobalite, and SiC particles and SiC fibres was assessed for 1687 long-term workers employed during 1913–2003 in the Norwegian SiC industry.
- Standardised incidence ratios for lung cancer, with follow-up during 1953–2008, were calculated stratified by cumulative exposure categories.
- Poisson regression analyses were performed using both categorised and log-transformed cumulative exposure variables.
- The lung cancer incidence was about twofold increased at the highest level of exposure to each of the exposure factors (standardised incidence ratios 1.9–2.3 for all agents).
- Internal analyses showed associations between exposure level and lung cancer incidence for all investigated factors, but a significant trend only for total dust and cristobalite. In multivariate analyses, cristobalite showed the most consistent associations, followed by SiC fibres.