Many consumers have known that high doses of ionizing radiation used for diagnosis of diseases and treatment of cancer can cause cancer. But studies like the one Dr. Ben D. Spycher at University of Bern in Switzerland and colleagues published in 2015 in the journal Environmental Health Perspectives have found even low doses of background ionizing radiation can increase the risk of cancer, particularly in children who are more sensitive to the damage induced by ionizing radiation.
The Swiss study was intended to examine whether low doses of ionizing radiation from natural background including terrestrial gamma and cosmic rays have an effect on the risk for some commonly seen cancers in children. Included in the survey were 2,093,660 children of whom 1,782 incident cases of cancer were recorded including 530 cases of leukemia, 328 cases of lymphoma, and 423 cases of central nervous system tumors. Cases were identified from the Swiss Childhood Cancer Registry.
Researchers were able to find that for each millisievert increase in the cumulative dose of background ionizing radiation, the risks for all cancers, leukemia, lymphoma and central nervous system tumors were increased by 3%, 4%, 1%, and 4%, respectively. All the associations were statistically significant. Adjustments for potential confounders did not change the associations, meaning that the risk-exposure correlations were stable.
The study concludes that background ionizing radiation may contribute to the risk of cancers like leukemia and central nervous system tumors in children.
Ionizing radiation is a known type of carcinogen and there is no denying of the harm induced by high doses of this type of radiation, which is commonly used for diagnostic tools like imaging instruments and cancer treatments like radiotherapy.
However, whether low doses of ionizing radiation have any cancer-causing effect remains controversial. Some scientists say there is no safe dose for ionizing radiation and exposure to any dose of this carcinogen increases the cancer risk to certain degree while some others downplay the potential risk.
Ionizing radiation from the natural background cannot be avoided, but residing in certain areas or regions can expose people to relatively high levels of natural background ionizing radiation. (David Liu)
Spycher BD, Lupatsch JE, Zwahlen M, Röösli M, Niggli F, Grotzer MA, Rischewski J, Egger M, Kuehni CE, for the Swiss Pediatric Oncology Group and the Swiss National Cohort. 2015. Background ionizing radiation and the risk of childhood cancer: a census-based nationwide cohort study. Environ Health Perspect 123:622–628; http://dx.doi.org/10.1289/ehp.1408548