Combined Occupational Exposure to Lead and Other Metals and Risk of Lung Cancer

BACKGROUND: The evidence linking occupational exposure to lead and cancer in humans is suggestive. Existing studies examine individual exposure to lead, ignoring the potential joint effects of mixed metal exposure. METHODS: We analyzed the data of a case-control study of lung cancer conducted in seven European countries and comprising 2,861 cases and 2,936 controls, with a detailed assessment of occupational exposure to arsenic, cadmium, chromium (VI), and lead, to estimate the odds ratio (OR) of lung cancer for combined exposure to lead and these other carcinogenic metals, after adjustment for potential confounders. RESULTS: The results suggested a synergism between lead and arsenic or cadmium: ORs were around 1.0 for lead alone and above 2.0 for combined exposure. No interaction was suggested between lead and chromium (VI). CONCLUSION: Our results provide suggestive evidence of a possible interaction between occupational exposure to lead, arsenic, or cadmium and lung cancer risk, and highlight the importance of considering mixed metal exposures in occupational epidemiology.