Cancer mortality in a cohort of male German iron foundry workers

BACKGROUND: Observations of an increased incidence of cancers of the upper aero-digestive tract (pharynx, esophagus, larynx, lung) among workers of local German foundries gave rise to concern about a potentially elevated occupational risk of those cancer sites. The purpose of the study was to examine whether occupational exposure in iron foundries increases the risk of cancer. METHODS: A historical cohort study of 17,708 male German production workers in 37 iron foundries who were first employed in 1950-1985 with a minimum employment period of 1 year was initiated. Employment and occupational histories were collected. Mortality was compared with that of the German general population during 1950-1993 using a new method for computing the SMR when not all causes of death are available (called SMR*). RESULTS: Mortality from all causes was elevated to SMR = 115.4 (95% confidence interval (CI) = 111.9-119.1), as was for total cancer (SMR* = 123.8, CI = 102.1-152.6), especially cancers of the lung (SMR* = 163.9, CI = 123.9-223.0) and liver (SMR* = 322.5, CI = 149.5-844.8), and diseases of the respiratory system (SMR* = 147.6, CI = 100.4-221.5). Non-significant elevations of mortality were also found for cancers of the mouth and pharynx (SMR* = 153.5, CI = 82.3-359.8) and larynx (SMR* = 173.1, CI = 85.5-550.5). Mortality from various causes of death was higher among workers with shorter exposure periods than among long-term employees. The elevated mortality persisted for years and decades after termination of employment. CONCLUSIONS: The results provide further evidence for an increased risk of lung cancer and possibly other cancers of the upper aero-digestive tract among foundry workers. Special attention should be paid to the strongly increased mortality from liver cancer and the mortality pattern among employees having terminated work.