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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/m3 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 3 and 4.8% were exposed to levels > 150 Bq/m3. 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.

Exposure to occupational carcinogens is often overlooked as a contributor to the burden of cancer. To estimate the proportion of cancer cases attributable to occupational exposure in Canada in 2011, exposure prevalence and levels of 44 carcinogens were informed by data from the Canadian carcinogen exposure surveillance project (CAREX Canada). These were used with Canadian Census (between 1961 and 2011) and Labour Force Survey (annual surveys between 1976 and 2013) data to estimate the number of workers ever exposed to occupational carcinogens. Risk estimates of the association between each carcinogen and cancer site were selected mainly from published literature reviews. Population attributable risks were estimated using Levin's equation and applied to the 2011 cancer statistics from the Canadian Cancer Registry. It is estimated that 15.5 million Canadians alive in 2011 were exposed, during at least one year between 1961 and 2001, to at least one carcinogen in the workplace. Overall, we estimated that in 2011, between 3.9% (95% CI: 3.1%-8.1%) and 4.2% (95% CI: 3.3%-8.7%) of all incident cases of cancer were due to occupational exposure, corresponding to lower and upper numbers of 7700-21,800 cases. Five of the cancer sites - mesothelioma, non-melanoma skin cancer, lung, female breast, and urinary bladder - account for a total of 7600 to 21,200 cancers attributable to occupational exposures such as solar radiation, asbestos, diesel engine exhaust, crystalline silica, and night shift work. Our study highlights cancer sites and occupational exposures that need recognition and efforts by all stakeholders to avoid preventable cancers in the future.

Outdoor workers are exposed daily to solar ultraviolet radiation, an important contributor in the development of non-melanoma skin cancer. This study aimed to quantify the health burden of non-melanoma skin cancers among outdoor workers in Canada. Solar ultraviolet radiation exposure and estimates of exposure levels were applied to employment information from Canada census data to determine the exposed population in the risk exposure period (1961–2001). Risk estimates were drawn from meta-analyses selected based on quality and relevance to the current study. Population-attributable fractions were calculated using Levin’s equation and attributable cases were estimated based on incidence data reported by the Canadian Cancer Society. In 2011, 6.31% (4556 cases) of non-melanoma skin cancer cases were estimated to be attributable to occupational exposure to solar ultraviolet radiation. The majority of these cases occurred in men in the agriculture or construction industries. These estimates of the burden of non-melanoma skin cancer in Canada identify the need for further prevention efforts, particularly in agriculture and construction. Introducing workplace sun safety measures could be an important area for policy development.

Background Only few risk factors have been identified for amyotrophic lateral sclerosis (ALS). Higher risks were reported for various occupations (e.g. farmers, construction workers), but responsible exposures remain largely unknown. We investigated the association between occupational exposure to diesel engine exhaust and sporadic ALS in a population-based study with detailed information on possible confounders. Methods An ongoing ALS case-control study is being conducted in the Netherlands since 2006, and we here present data for 2006–2014. Lifetime occupational histories and lifestyle factors were collected via questionnaires. A general population job-exposure matrix was assigned to estimate exposure to diesel engine exhaust. All exposure variables were estimated up to two years before survey to account for any changes due to disease onset. Odds ratios were estimated by logistic regression models, adjusted for age, sex, smoking and alcohol. Results Data were available for 1040 sporadic ALS cases (63.6% male) and 2050 controls (60.2% male). Ever occupational exposure to diesel engine exhaust was not associated with risk of ALS (OR=1.06, 95% CI 0.87–1.28). No exposure-response relation was observed for either cumulative exposure or exposure duration on a continuous scale. Conclusion Our analysis suggests that exposure to diesel engine exhaust is not associated with an increased risk of ALS.

BackgroundRadon is a well-known cause of lung cancer. Our goal was to estimate the prevalence and level of occupational exposure to radon, and to estimate the current lung cancer burden caused by radon exposure in Canadian workplaces.MethodsHighly exposed (i.e. underground) workers were assigned exposure proportions at the national level using CAREX methodology. Exposure for the indoor working population was estimated using province-specific radon measurements from the Canadian federal building survey (n=12 870 samples). The proportion of workers exposed to specific ranges of radon (50–100, 100–150, 150–200, 200–400, 400–800,>800 Bq/m3) were calculated and we assigned the midpoint of the range as the average radon concentration for each exposure group. For the >800 Bq/m3category, the province-specific mean of measurements>800 Bq/m3was assigned. The above exposure assessment was applied to a population model of the historical Canadian labour force and exposures between 1961 and 2001 (the risk exposure period) were considered as contributing to cancer cases in 2011. The BEIR VI exposure-age-concentration model was used to assign relative risks by exposure category. The population attributable fraction was calculated using Levin’s equation.ResultsThere were an estimated 4.4 million indoor workers and 26 000 highly exposed workers exposed to radon during the risk exposure period. Nearly 80% of these workers were exposed below 50 Bq/m3 (half the WHO reference level). Combining the indoor and highly exposed workers, we calculated that 0.80% of lung cancers are attributable to occupational radon exposure; this equates to 188 lung cancer cases per year.ConclusionsOurs was the first study to use a data-driven approach to estimate radon exposure and lung cancer burden for indoor workers. Some of the attributable cases can be prevented by reducing workers’ exposure at workplace.

Objective Cancer is the second-leading cause of death in Latin America and the Caribbean (LAC). Exposure to workplace carcinogens is an important factor, yet there are sparse data about the numbers and types of LAC workers exposed. This project aimed to build capacity for CARcinogen EXposure (CAREX) programs in LAC. Methods The CAREX method, originally developed in the European Union for estimating exposure to occupational carcinogens, has been used and modified in some Central American countries and Canada. Generally, the approach combines labour force data with estimates of the proportions of workers exposed to priority carcinogens in each country. A two-day workshop involving over 20 participants from Canada and 12 LAC countries was held to discuss methodological approaches, issues unique to LAC, and research opportunities. Certain individual countries subsequently developed CAREX programs by holding consultations to identify priority carcinogens and adapting proportion of exposure values from existing CAREX programs. Results CAREX programs in LAC have been established in Costa Rica, Nicaragua, Panama, Guyana, Colombia, Peru, and Chile. Central American CAREX projects included exposure estimates by sex for approximately 30–35 carcinogens that incorporated levels of uncertainty. Both informal and formal workers were covered in exposure estimates, although estimates for these populations are challenging in most countries. In general, agents with the greatest prevalence of exposure in all industries included solar radiation, environmental tobacco smoke, crystalline silica, and pesticides. In Peru, exposure estimates were based on data from LAC and Europe with the involvement of experts from 43 institutions. Preliminary results from Chile have also been produced using a slight variation of this approach. Conclusions This project demonstrates that the CAREX methodology can be readily adapted to different countries, economies, and priority carcinogens. CAREX exposure estimates are integral for informing primary prevention activities and improving estimates of the global occupational cancer burden.