Cancer mortality in the asphalt industry: a ten year follow up of an occupational cohort.

A historical cohort study was conducted to study the possible risk of cancer associated with exposure to asphalt. Altogether 1320 unskilled workers employed in the asphalt industry were followed up over a ten year period and compared with 43,024 unskilled men in terms of cause specific mortality. Both groups were identified from census records and followed up by an automatic record link that had been established previously between the census register, National Register, and Death Certificate Register. The cancer mortality was significantly increased in asphalt workers aged 45 or more, when five years' latency from enrolment into the study was allowed for (SMR for cancer: 159, 95% confidence interval: 106-228). Non-significant increases were seen for respiratory, bladder, and digestive cancers but a significant increase was seen for brain cancer (SMR = 500, 95% CI: 103-1461). Components of asphalt fumes may have been important to the observed association between risk of cancer and employment in the asphalt industry.