Authors:
By Cheryl Young MD CCFP (biography and disclosures) and David McVea MD PhD FRCPC (biography and disclosures)
Dr. Young Disclosures: Dr. Young completed a residency rotation at BCCDC, which developed and hosts the radon exposure map described. Mitigating potential bias: Development of radon-awareness materials was within Dr. Young’s responsibilities during her rotation at BCCDC and she did not receive any additional payment for this work. Recommendations are consistent with current public health practice.
Dr. McVea Disclosures: Dr. McVea is employed by BCCDC, which developed and hosts the radon exposure map described. Mitigating potential bias: Development of radon-awareness materials is within Dr. McVea’s responsibilities at BCCDC and he does not receive any additional payment for this work. Recommendations are consistent with current public health practice.
What care gaps have we noticed
There are approximately 3,000 lung cancer deaths in Canada attributable to radon exposure each year,1 but there is limited awareness of radon both among the public and health care providers. In conversations with colleagues and patients, we noticed that few know what radon is, how it contributes to lung cancer, and the strong synergistic effects of radon and smoking. By assessing the risk of radon-attributable lung cancer, patients can make informed decisions about protecting themselves from radon, as well as smoking cessation.
Data that answers these questions or gaps
Radon is a naturally occurring colourless, odourless, radioactive gas that is released when uranium breaks down in soils and rocks. Radon can seep into a home through any opening that is in contact with the ground, such as through cracks in the foundation, gaps around pipes, floor drains, and window casements. It is long-term exposure to radon in the basement and lower floors of a building, where radon can accumulate, that increases the risk of lung cancer.
Health Canada estimates that radon is responsible for about 16% of lung cancer deaths, making it the leading cause of lung cancer for non-smokers and the second leading cause for smokers.1 Radon is measured Becquerels per cubic meter (Bq/m3) and Health Canada recommends that homes with exposure to radon above 200 Bq/m3 get remediation within two years and homes above 600 Bq/m3 get remediation within one year (for reference, radon released outdoors gets diluted to 0-15 Bq/m3, which poses negligible risk to health).2
Importantly, the interaction between radon and smoking produces a synergistic effect for lung cancer risk.3 Even at lower levels of radon exposure, smokers have a much higher increase in lung cancer risk due to radon than non-smokers. At low levels of radon exposure, below 100 Bq/m3, the lower estimate of the lifetime risk for lung cancer is 1% for non-smokers and 12% for ever-smokers. At 200 Bq/m3, the risks are 2% and 17% respectively, and above 600 Bq/m3, they are 4% and 26%.4
Exposure to indoor radon varies across the province, largely depending on geological factors. As visualized in a newly developed map of radon levels recorded in homes in BC, the Northern and Interior Health Authorities are known to have higher levels of radon exposure.5 Housing characteristics such as how much of the foundation of the home was sealed during its construction and how much ventilation occurs also influence the accumulation of radon, so radon levels can vary from house to house, even in the same neighborhood.
The only way to know how much radon is in a home is by testing for it, and there are now low-cost D-I-Y testing devices that can be purchased online or at home improvement stores. If a home has high levels of radon, it can be remediated to prevent radon from entering and accumulating. An excellent starting point to learn about radon testing and remediation is at www.bccdc.ca/radon.
What we recommend
Physicians should be aware if they practice in an area with higher levels of radon, which can be determined on the BCCDC webpage and map. Patients should be encouraged to consider their exposure to radon and its effect on their risk of lung cancer. Important factors to consider are smoking history and whether they live within high-radon communities.
A key opportunity to discuss radon is during smoking cessation counselling. At all levels of radon exposure, but especially in high-radon areas, the combined effect of radon and smoking can be an additional motivator to quit. A free smoking cessation program for British Columbians can be found at quitnow.ca. Those who face challenges with smoking cessation should be aware of their higher risk of radon-attributable lung cancer and should consider testing and remediating their home.
Other opportunities to mention radon include prenatal care visits and well-baby/well-child visits, when counselling is already being provided about other home safety considerations (baby proofing, carbon monoxide, fire detectors, etc.). While conducting a Periodic Health Review, during the social history when asking about living situations, and the family history when asking about cancers, are more opportunities for physicians to ask about a patient’s awareness of radon.
For patients who want to learn more about radon, there are a number of resources that they can be referred to, including the BCCDC, BC Lung Foundation, BC Cancer, and Health Canada.
References
- Chen J, Moir D, Whyte J. Canadian population risk of radon induced lung cancer: a re-assessment based on the recent cross-Canada radon survey. Radiat Prot Dosimetry. 2012;152(1-3):9-13. doi:10.1093/rpd/ncs147 (View)
- Health Canada. Guide for Radon Measurements in Residential Dwellings (Homes): Minister of Health; 2017. 24 p. Cat.: H128-1/08-543-2E-PDF. (View on www.canada.ca) Accessed Nov 1, 2022
- National Research Council (US) Committee on Health Risks of Exposure to Radon (BEIR VI). Health Effects of Exposure to Radon: BEIR VI. Appendix C, Tobacco-Smoking and Its Interaction with Radon. Washington (DC): National Academies Press (US); 1999. (View on www.ncbi.nlm.nih.gov) Accessed Nov 1, 2022
- Chen J. Canadian individual risks of radon-induced lung cancer for different exposure profiles. Can J Public Health. 2005;96(5):360-363. doi:10.1007/BF03404033 (View)
- BC Centre for Disease Control. Radon. British Columbia: Provincial Health Service Authority;2021. (View on www.bccdc.ca) Accessed Nov 1, 2022
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Last time I looked this up a couple of years ago there were studies in some countries showing radon was associated with lower cancer rates, but higher in others, and that the pooled results show no effect worldwide. Seems like the reason there is very limited uptake on this is that our best evidence is that this isn’t an actual issue.
Thank you for this article – I recall reading about the implication of radon in lung cancer during medical school, so I’m glad to read your article on the subject matter.
Good info thanks. I was aware but the links are useful
Thank you for this topic. I now have more information on how best to introduce the topic of Radon exposure and the risk of lung cancer to my patients.
I would be interested in learning more about the statistics around radon and lung cancer in smokers
Good reminder-is ther any mapping for other areas in Canada?
Great article and very informative.
Appreciate all the links to practical tools – one question I have is, besides testing for radon, what is the intervention and how costly is it for most homeowners? Also, is this something a renter has a right to? How do you see this testing and remediation affecting patients of differing SES? Thanks!
FYI, many public libraries in BC have radon detectors available to borrow (but not always for long enough as recommended to get an accurate reading).
great source for identifying hazards
Are there any studies involving screening for lung cancer in high radon areas, such as we do for heavy smokers
Radon is in the air we breathe, but there may be things you can do to lower your exposure. The only way to be sure if radon is present or not is to test for it because being exposed to radon for a long period of time can lead to lung cancer.
In response to Jason (Nov 2).
Here is what WHO has to say:
https://www.who.int/news-room/fact-sheets/detail/radon-and-health#:~:text=Radon%20is%20one%20of%20the,of%20radon%20and%20cigarette%20smoking.