Latency and the lung cancer epidemic among United States uranium miners.

The latency of occupational cancer was a key factor in the recent epidemic of lung cancer among U.S. uranium miners. A review of the epidemic and analysis of latency periods with a near lifetime follow-up found that among former and nonsmokers, the mean mid-induction latent period is nearly a constant at about 25 y, regardless of age at starting or magnitude of exposure. Among cigarette smokers, the mean is shorter (about 19 y). It is not influenced by age at start of smoking, amount smoked, or magnitude of exposure, but there is a marked shortening as the age at start of radiation exposure rises. These latency variables affect lifetime risk models. By disregarding the European radon mine exposures and waiting for strong evidence of lung cancer among U.S. uranium miners (ignoring the exposures occurring while waiting during the latency period), the epidemic became inevitable.