The results of a study titled Mortality (1950–1999) and cancer incidence (1969–1999) of workers in the Port Hope cohort study exposed to a unique combination of radium, uranium and γ-ray doses have recently been published on BJM Open, which describes itself as follows: “An open access, online-only general medical journal dedicated to publishing research from all disciplines and therapeutic areas”.
I like to start with the conclusion first:
In one of the largest cohort studies of workers exposed to radium, uranium and γ-ray doses, no significant radiation-associated risks were observed for any cancer site or cause of death. Continued follow-up and pooling with other cohorts of workers exposed to by-products of radium and uranium processing could provide valuable insight into occupational risks and suspected differences in risk with uranium miners.
The study took advantage of a unique population of workers who were carefully monitored for their exposures while employed in a place with a unique environment of uranium, radium and gamma ray exposures. It evaluated those workers health outcomes for 50 years. The results of the study add to the deepening pile of information that shows that the health effects of low doses of radiation and ingestion of small amounts of radioactive material are not well predicted by the linear, no threshold dose (LNT) response assumption.
As doses fall into the range associated with normal industrial handling, they also fall into the range at which the processes of adaptive response and repair mechanisms that are a evolved features of multi-cellular creatures can completely correct any damage. As is the case for small doses of almost any substance or physical activity, doses in the range of interest appear to have a somewhat beneficial overall effect due to response stimulation.
I will leave you with a quote from the “results” section of the report:
Overall, workers had lower mortality and cancer incidence compared with the general Canadian population. In analyses restricted to men (n=2645), the person-year weighted mean cumulative RDP (radon daughter product) exposure was 15.9 working level months (WLM) and the mean cumulative whole-body γ-ray dose was 134.4 millisieverts. We observed small, non-statistically significant increases in radiation risks of mortality and incidence of lung cancer due to RDP exposures (excess relative risks/100 WLM=0.21, 95% CI <−0.45 to 1.59 and 0.77, 95% CI <−0.19 to 3.39, respectively), with similar risks for those exposed to radium and uranium. All other causes of death and cancer incidence were not significantly associated with RDP exposures or γ-ray doses or a combination of both.