Cancer incidence among short- and long-term workers in the Norwegian silicon carbide industry

Abstract

OBJECTIVES: A previous study among workers in the Norwegian silicon carbide industry, followed until 1996, revealed an excess incidence of lung and total cancer. The present study adds nine years of follow-up and focuses on cancer risk among short- and long-term workers, based on the assumption that these two groups have different exposure and lifestyle characteristics. METHODS: The total cohort for this study comprised 2612 men employed for >6 months between 1913 and 2003. The follow-up period for cancer was 1953–2005. Short-term workers were defined as having <3 years of total employment in the industry. We estimated standardized incidence ratios (SIR) using national rates as the expected values. RESULTS: Among the short-term workers, we observed an overall excess incidence of cancer [SIR 1.4, 95% confidence interval (95% CI) 1.2–1.6], with an excess of lung cancer (SIR 2.6, 95% CI 1.9–3.5) as the most important contributing factor. The long-term workers also had an excess incidence of total cancer (SIR 1.2, 95% CI 1.1–1.3) and lung cancer (SIR 1.7, 95% CI 1.3–2.2). We also observed an increased risk of cancers at other sites, specifically among short-term workers. CONCLUSIONS: We observed an increased risk of cancer (especially in the lung but also at other sites) among both short- and long-term workers. Dust exposure in the silicon carbide industry may have contributed to the increased risk among long-term workers, whereas the increased risk among short-term workers may be due to a combination of occupational and lifestyle factors.

Keywords

• smoking
• worker
• lung
• norway
• neoplasm
• lung neoplasm
• dust exposure
• short-term worker
• silicon carbide industry
• long-term worker
• epidemiology
• cancer incidence
• cancer
• incidence