Estimating the burden of lung cancer in Canada attributed to occupational radon exposure using a novel exposure assessment method

Abstract

Objective Exposure to radon causes lung cancer. The scope and impact of exposure among Canadian workers have not been assessed. Our study estimated occupational radon exposure in Canada and its associated lung cancer burden. Methods Exposed workers were identified among the working population during the risk exposure period (1961-2001) using data from the Canadian Census and Labour Force Survey. Exposure levels were assigned based on 12,865 workplace radon measurements for indoor workers and assumed to be 1800 mg/m 3 for underground workers. Lung cancer risks were calculated using the Biological Effects of Ionizing Radiation (BEIR) VI exposure-age-concentration model. Population attributable fractions were calculated with Levin's equation and applied to 2011 Canadian lung cancer statistics. Results Approximately 15.5 million Canadian workers were exposed to radon during the risk exposure period. 79% of exposed workers were exposed to radon levels < 50 Bq/m 3 and 4.8% were exposed to levels > 150 Bq/m 3. We estimated that 0.8% of lung cancers in Canada were attributable to occupational radon exposure, corresponding to approximately 188 incident lung cancers in 2011. Conclusions The lung cancer burden associated with occupational radon exposure in Canada is small, with the greatest burden occurring among those exposed to low levels of radon.

Relationships among Indoor Radon, Earthquake Magnitude Data and Lung Cancer Risks in a Residential Building of an Apulian Town (Southern Italy)

“…Radon-attributable lung cancer deaths for all 66 countries totaled 226,057 in 2012 and represented a median of 3.0% of total cancer deaths [77]. Recently, multiple published studies have measured the risk of developing lung cancer following residential or occupational radon exposure in various regions of the world, as well as the synergistic effect of cigarette smoking and the effect in never-smokers [8][9][10]73,[77][78][79][80][81] as well as analyzing the histological types of lung cancer [82].…”

“…In the near future, a study of the annual urban radon average will be conducted with the newly studied monitoring system, and appropriate measures addressing radon should be undertaken in areas of increased exposure to this noble gas to obtain longitudinal analyses of the risk of populations resulting from indoor radon exposure [73]. Monitoring the exposure of resident populations is relevant in light of the small lung cancer burden associated with occupational radon, with the greatest burden occurring among those exposed to low levels of radon [8,80,[85][86][87].…”

Characterizing occupational radon exposure greater than 100 Bq/m3 in a highly exposed country

“…While greater lung cancer risk is associated with increasing level of radon exposure 7 , no safe level of radon exposure exists 37 , and studies have reported positive associations between relatively low indoor radon concentrations and lung cancer risk 8 . CAREX Canada’s exposure estimates for 2006 were previously applied to estimate the burden of lung cancer cases associated with occupational radon exposure in Canada 38 – 40 . The results showed that while there is a relatively small lung cancer burden associated with occupational radon exposure overall (0.8% of lung cancers were attributable to occupational radon exposure, compared to 17.5% for tobacco smoking, and 0.8% for second-hand tobacco smoke exposure 41 ), low level exposures accounted for the majority of the burden 38 .…”

“…CAREX Canada’s exposure estimates for 2006 were previously applied to estimate the burden of lung cancer cases associated with occupational radon exposure in Canada 38 – 40 . The results showed that while there is a relatively small lung cancer burden associated with occupational radon exposure overall (0.8% of lung cancers were attributable to occupational radon exposure, compared to 17.5% for tobacco smoking, and 0.8% for second-hand tobacco smoke exposure 41 ), low level exposures accounted for the majority of the burden 38 . Of the 188 lung cancer cases attributable to occupational radon exposure during the risk exposure period (1961–2001), 139 cases (or 74%) were associated with radon levels less than 200 Bq/m 3 due to the very large size of the population exposed at this level 38 .…”

“…Despite evidence of lung cancer risk associated with low level exposures to radon 8 , 38 , existing radon guidelines for the workplace remain inadequate. The United States Environmental Protection Agency (US EPA) recommends dwellings be remediated to reduce radon levels if concentrations exceed 4 pCi/L (picocuries per litre), equivalent to 148 Bq/m 3 42 .…”