Objectives The aim of this study was to investigate cancer risk among Norwegian workers in the printing industry, particularly lung and bladder cancer.

Methods Cancer incidence was investigated from 1953 through 1998 in a cohort of 10 549 male members of a trade union in the printing industry in Oslo and nearby areas. Rates from the region, were used to calculate standardized incidence ratios (SIR) separately for the skilled and unskilled workers. Smoking data from a sample of the cohort were utilized for evaluating the risk estimates of smoking-related cancers. Specific exposure data were not available.

Results Among the skilled workers, significantly elevated risks of cancer of the urinary bladder [standardized incidence ratio (SIR) 1.47, 95% confidence interval (95% CI) 1.19–1.79], liver (SIR 1.92, 95% CI 1.15–2.99), pancreas (SIR 1.46, 95% CI 1.07–1.94) and colon (SIR 1.27, 95% CI 1.05–1.55) were observed, whereas an increased risk of lung cancer in this group was confined to those born before 1910. Among the unskilled workers, there were significantly increased risks of cancer of the mouth, esophagus, stomach, larynx, lung, and all sites.

Conclusions The study showed that workers in the printing industry were at increased risk of several types of cancer. In particular the increased risk of bladder cancer among the skilled workers is suggestive of an occupational cause. However, no specific agent could be identified as an occupational carcinogen. The results did not support the hypothesis of a generally increased risk of lung cancer. The risk pattern for unskilled workers may reflect confounding by nonoccupational factors.

Key terms bladder cancer; cancer; cohort study; liver cancer; male; Norway; occupation; printing industry; social class; trade-union member