Cancer incidence among short- and long-term workers in the Norwegian silicon carbide industry.
OBJECTIVE
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.
Bugge
Merete Drevvatne
MD
National Institute of Occupational Health, N-0033 Oslo, Norway. mdb@stami.no.
Kjuus
Helge
H
Martinsen
Jan Ivar
JI
Kjærheim
Kristina
K
D000395:Air Pollutants, Occupational / Q000009:adverse effects*; D017554:Carbon Compounds, Inorganic / Q000009:adverse effects*; D004391:Dust; D019652:Extraction and Processing Industry; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008175:Lung Neoplasms / Q000453:epidemiology* / Q000209:etiology; D009664:Norway; D016273:Occupational Exposure / Q000009:adverse effects / Q000706:statistics & numerical data*; D017655:Silicon Compounds / Q000009:adverse effects*
D000395:Air Pollutants, Occupational; D017554:Carbon Compounds, Inorganic; D004391:Dust; D017655:Silicon Compounds; C022088:silicon carbide