Mortality from non-malignant diseases among male Norwegian asphalt workers

BACKGROUND: The possible associations between asphalt work and mortality from non-malignant diseases in a cohort of male Norwegian asphalt workers that formed part of the European asphalt worker mortality study are examined. METHODS: The mortality experience among 8,610 male workers ever employed in asphalt work was observed from 01.01.1970 until 12.31.1996, yielding 127,636 person years of observation. The cause-specific deaths observed in the study cohort were compared with the expected figures calculated from 5-year period- and age-specific national death rates. A study-specific job exposure matrix was used for individual-individual exposure estimates. RESULTS: Eight hundred and three workers died during the observation period (SMR = 0.92, 95% confidence intervals (CI) = 0.58, 1.40). The mortality from non-malignant respiratory diseases was elevated (SMR = 1.25, 95%CI = 0.97, 1.58) and was associated with years since first employment in the asphalt industry. Mortality from respiratory diseases was highest among the workers first employed in the 1960s. Among the different job types held by the workers the pavers and mastic asphalt workers had the highest mortality from respiratory diseases. A weak dose-response was found with cumulative exposure to PAH and bitumen fume and mortality from non-malignant respiratory diseases in analyses employing the job-exposure matrix. Overall mortality, the mortality from circulatory diseases (SMR = 0.93, 95%CI = 0.83, 1.03) and external causes (SMR = 0.90, 95%CI = 0.72, 1.11) was lower than expected. CONCLUSIONS: Mortality from respiratory diseases was found somewhat elevated among the asphalt workers. There was some evidence of exposure-response with both bitumen fume and PAH exposure. PAH from coal tar contributes to the PAH exposure.