EXCESS LUNG-CANCER AMONG WORKERS EXPOSED TO LEAD

Objective Studies on experimental animals suggest that inorganic lead is a carcinogen. The purpose of the study was to examine whether occup ational exposure to lead increases the risk of cancer. Methods The stu dy population comprised 20 700 workers who had been biologically monit ored for their blood lead (B-Pb) concentrations during 1973-1983. The mortality and cancer incidence rates were followed among the monitored workers and compared with those of the Finnish general population. An internal comparison of the cancer incidence rates was also done betwe en subcohorts formed according to individual B-Pb levels. Questionnair e-based information was also collected on lifetime occupational histor y and potential confounders, and exposure history was assessed on an i ndividual basis with a nested case-referent design for lung cancer. Re sults The internal comparison within the cohort showed a 1.4-fold incr ease in the overall cancer incidence and a 1.8-fold increase in the in cidence of lung cancer among those who had ever had a blood lead level of greater than or equal to 1.0 mu mol . 1(-1). In the case-referent study, an increased odds ratio for lung cancer was found for concomita nt exposure to lead and engine exhaust. The odds ratio for squamous-ce ll carcinoma of the lung was increased even when the blood lead level had been slightly elevated. Bias or confounding did not explain the ri sks. Conclusions The results suggest that exposure to lead increases t he risk of lung cancer. Go-exposure to engine exhaust and lead may be associated with the risk.