Objectives The aim of this investigation was to study the cancer mortality of Chinese copper miners and smelters further, with particular reference to that from lung cancer, and smoking prevalence.

Methods From an earlier follow-up (1970--1985) of the mortality of the two cohorts, all new death cases registered since 1985 were recorded, and the mortality analysis was extended through 1992. A questionnaire survey of smoking habits was carried out in three samples, randomly chosen from the copper miners (N=1125), smelters (N=603), and local residents (N=1517) of Tongling city.

Results Lung cancer was significantly increased among the copper miners [standardized mortality ratio (SMR) 152, 95% confidence interval (95% CI) 123--187], but not among the copper smelters (SMR 102, 95% CI 53--178). Smoking was more prevalent among copper miners than among local male residents (71.7 versus 64.3%, P<0.001), whereas among the smelters it was significantly less prevalent (57.4 versus 64.3%, P<0.005). Similar patterns were found for the average number of cigarettes smoked daily among the miners (21.6±7.2), smelters (15±7.1), and local male residents (19.2±7.3).

Conclusion In addition to occupational exposures, cigarette smoking may partly play a role in influencing mortality from lung cancer among Chinese copper miners and smelters.

Key terms cancer risk; cigarette smoking; cohort study; occupational exposure