Lung cancer and smoking in a group of iron ore miners.

Several studies have shown that miners, in both uranium and nonuranium mines, have an increased lung cancer mortality, probably caused by exposure to radon and its daughters. The excess mortality has been observed primarily among smoking miners but some recent studies have also indicated a considerably increased risk among nonsmoking miners. This study, among a group of iron ore miners, was undertaken to further elucidate the somewhat unclear and presumably complex relationship of mining, smoking, and lung cancer. The results show a 16-fold increase in lung cancer mortality among miners versus nonminers. Even nonsmoking miners seem to be at a rather high risk of developing lung cancer, but there was a tendency for the most heavy smoking miners to die earlier and to have a slightly shorter induction-latency period for development of lung cancer than was found among the nonsmoking miners.