Carpal tunnel syndrome among Manitoba workers: Results from the Manitoba Occupational Disease Surveillance System.

BACKGROUND: Carpal tunnel syndrome (CTS) is associated with occupational high-force repetitive tasks and vibration. This project examines the relationship between CTS and work to: (1) identify jobs and industries with increased CTS risk; (2) explore whether there is a sex difference in the risk of CTS after controlling for occupation; and (3) determine whether any observed relationships persist after excluding Workers Compensation Board (WCB) accepted time-loss CTS claims. METHODS: We linked 95.5% of time-loss WCB claims from 2006 to 2019 to provincial administrative health data. The cohort included 143,001 unique person-occupation combinations. CTS cases were defined as at least two medical claims for (ICD-9 354) within a 12-month period or a surgical claim for CTS from 2 years before the WCB claim to 3 years after. WCB accepted CTS time-loss claims not identified by the medical claims were also included. RESULTS: A total of 4302 individuals (3.0%) met the CTS definition. Analysis revealed that the hazard ratios (HRs) of CTS vary considerably with occupation. Sex-based differences in CTS risks were observed, both in low- and high-risk occupations. In many occupations with increased HR, the HR remained elevated after excluding accepted time-loss WCB cases. CONCLUSIONS: The risk of developing CTS varied with occupation. Job titles with ergonomic risk factors had higher risks than those with lower exposures. This finding remained after eliminating time-loss compensated WCB cases, suggesting that all cases of CTS in high risk jobs are not identified in WCB statistics. Female workers in some job titles had excess CTS cases compared to male workers within the same job title.

Exposure to low-dose radiation in occupational settings and ischaemic heart disease: a systematic review and meta-analysis.

Ionising radiation is a human carcinogen, but the evidence is less clear that exposure to low-dose ionising radiation (LDIR) increases the risk of adverse cardiovascular outcomes. We synthesised the literature of chronic occupational exposure to LDIR and cardiovascular disease, particularly for ischaemic heart disease (IHD).The literature search was conducted using three databases including studies published between 1990 and 2022. A quality assessment of the studies was completed using the Office of Health and Assessment and Translation Risk of Bias Rating Tool. We conducted meta-analyses for IHD mortality using random effects models using measures of excess relative risk per sievert (ERR/Sv) obtained from internal cohort comparisons, as well as with standardised mortality ratios (SMRs) from external cohort comparisons.We identified 2189 articles, and of these, 26 provided data on IHD and were retained. Most studies were classified as having a 'moderate' level of risk of bias. Fourteen and 10 studies reporting external radiation doses were included in meta-analyses using SMR and ERR/Sv, respectively. The meta-summary SMR was 0.81 (95% CI 0.74 to 0.89) with evidence of reduced risk but high heterogeneity across studies. For internal cohort measures, the summary ERR/Sv for a lagged exposure of 10 years was 0.10 (95% CI 0.01 to 0.20) with low heterogeneity. The subgroup analysis by lagged exposure time showed the strongest association were for the 15 and 20 years lag.Our findings suggest that occupational exposure to LDIR increases the risk IHD mortality and highlight the relevance of internal cohort comparisons.

Impact of Playground Shade Structures on Ultraviolet Radiation Exposure and Physical Activity among Children at a Childcare Facility.

Skin cancer is the most common cancer in Canada, and rates continue to rise. While sunscreen and protective clothing remain critical strategies to reduce skin cancer risk, shade is generally the most effective way to control exposure. There remains a lack of data, particularly in British Columbia (BC), demonstrating the extent to which shade availability reduces ultraviolet radiation (UVR) exposure in a real-world setting and the potential impacts of shade provision on physical activity. We evaluated the impact of shade structures on UVR exposure and physical activity at a Vancouver-area childcare center with an outdoor play area with limited existing shade. 22 children, aged 3-5 years, participated in the study. Three removable shade sails were installed in the outdoor play space, and UVR and physical activity measurements were collected during the spring, summer, and fall months. Ultraviolet B (UVB) radiation data was measured using UVB dosimeters, and physical activity data was measured using accelerometers. Data were collected during each season over a total of four days-two days with shade sails installed and two days with shade sails removed. Overall, with shade installation, UVR exposures and physical activity levels among children were reduced by 50% and 20%, respectively. This study supports the use of shade sails to significantly reduce UVR exposures among preschool-aged children in BC; however, the potential for decreased physical activity from shade sails should be further explored in future research.

Time spent in the sun and the risk of developing non-Hodgkin lymphoma: a Canadian cohort study.

PURPOSE: The objective was to explore the relationship of sun behavior patterns with the risk of developing non-Hodgkin lymphoma (NHL). METHODS: Sun behavior information from Alberta's Tomorrow Project, CARTaGENE, and Ontario Health Study were utilized. The relationship between time in the sun during summer months and risk of NHL was assessed using Cox proportional hazard models with age as the time scale and adjustment for confounders. Cohorts were analyzed separately and hazard ratios (HR) pooled with random effects meta-analysis. Joint effects of time in the sun and use of sun protection were examined. Patterns of exposure were explored via combinations of weekday and weekend time in the sun. RESULTS: During an average follow-up of 7.6 years, 205 NHL cases occurred among study participants (n = 79,803). Compared to < 30 min daily in the sun, we observed HRs of 0.84 (95% CI 0.55-1.28) for 30-59 min, 0.63 (95% CI 0.40-0.98) for 1-2 h, and 0.91 (95% CI 0.61-1.36) for > 2 h. There was suggestive evidence that > 2 h was protective against NHL with use of sun protection, but not without it. Compared to < 30 min daily, moderate exposure (30 min to 2 h on weekdays or weekend) was associated with a lower risk of NHL (HR 0.63, 95% CI 0.43-0.92), while intermittent (< 30 min on weekdays and > 2 h on weekends) and chronic (> 2 h daily) were not. CONCLUSION: This study provides evidence of a protective effect of moderate time spent in the sun on NHL risk.

Inequalities in Environmental Cancer Risk and Carcinogen Exposures: A Scoping Review.

Background: Cancer is the leading cause of death in Canada and a major cause of death worldwide. Environmental exposure to carcinogens and environments that may relate to health behaviors are important to examine as they can be modified to lower cancer risks. Built environments include aspects such as transit infrastructure, greenspace, food and tobacco environments, or land use, which may impact how people move, exercise, eat, and live. While environments may play a role in overall cancer risk, exposure to carcinogens or healthier environments is not equitably spread across space. Exposures to carcinogens commonly concentrate among socially and/or economically disadvantaged populations. While many studies have examined inequalities in exposure or cancer risk, this has commonly been for one exposure. Methods: This scoping review collected and synthesized research that examines inequities in carcinogenic environments and exposures. Results: This scoping review found that neighborhoods with higher proportions of low-income residents, racialized people, or same-sex couples had higher exposures to carcinogens and environments that may influence cancer risk. There are currently four main themes in research studying inequitable exposures: air pollution and hazardous substances, tobacco access, food access, and other aspects of the built environment, with most research still focusing on air pollution. Conclusions: More work is needed to understand how exposures to these four areas intersect with other factors to reduce inequities in exposures to support longer-term goals toward cancer prevention.

Acute myocardial infarctions identified in the Manitoba Occupational Disease Surveillance System: A linkage of worker's compensation and provincial health data.

INTRODUCTION: The purpose of this study was to identify jobs and industries that may be associated with increased or decreased risk of myocardial infarction. METHODS: We linked provincial health care data with Workers Compensation Board (WCB) of Manitoba claims data to create the Manitoba Occupational Disease Surveillance System (MODSS). Workers were eligible for inclusion in this study if their WCB claim listed an occupation, their claim could be linked to health data, they had an accepted non-acute myocardial infarction (AMI) compensation time loss claim and were free of a recent (<1 year) AMI diagnosis at the start of disease follow-up. AMI cases were identified as the most-responsible diagnosis in the hospitalization file (ICD-9 410 or ICD-10 I20). Cases were included if they occurred after the WCB record injury date until end of coverage, either through moving out of province, reaching age 65, death, or the end of the study period (March 1, 2020). RESULTS: We identified 1880 incident AMIs amongst 150,022 claims recorded in the MODSS (1.25%). A number of industries and occupations were found to have higher and lower AMI rates. Care providers and educational, legal, and public protection support occupations had a lower hazard ratio (HR; 0.64; 95% confidence interval [CI]: 0.44-0.92) compared to the overall cohort. Female chefs and cooks, and male butchers and bakers had elevated AMI HRs. Both male and female transport and heavy equipment operators and related maintenance occupations had increased HRs (1.48; 95% CI: 1.30-1.67). Often male and female workers employed in the same occupations had congruent AMI risks, but this was not always the case. CONCLUSIONS: The linkage of a WCB data set with provincial health claims data led to the identification of a number of occupations with elevated risks of AMI in Manitoba. This was most notable in the transportation industry. Identifying work areas with increased risk of AMIs could lead to targeted educational efforts and potential workplace modifications to lower this risk.

Consequences of changing Canadian activity patterns since the COVID-19 pandemic include increased residential radon gas exposure for younger people.

The COVID-19 pandemic has produced widespread behaviour changes that shifted how people split their time between different environments, altering health risks. Here, we report an update of North American activity patterns before and after pandemic onset, and implications to radioactive radon gas exposure, a leading cause of lung cancer. We surveyed 4009 Canadian households home to people of varied age, gender, employment, community, and income. Whilst overall time spent indoors remained unchanged, time in primary residence increased from 66.4 to 77% of life (+ 1062 h/y) after pandemic onset, increasing annual radiation doses from residential radon by 19.2% (0.97 mSv/y). Disproportionately greater changes were experienced by younger people in newer urban or suburban properties with more occupants, and/or those employed in managerial, administrative, or professional roles excluding medicine. Microinfluencer-based public health messaging stimulated health-seeking behaviour amongst highly impacted, younger groups by > 50%. This work supports re-evaluating environmental health risks modified by still-changing activity patterns.

Barriers and Facilitators in the Creation of a Surveillance System for Solar Radiation-Induced Skin Cancers.

Outdoor workers are exposed to many hazards, including solar ultraviolet radiation (UVR). Identifying, reporting, analyzing and tracking the exposures or health outcomes of outdoor workers have not generally been formally considered. This article aims to summarize the best practices/strategies for creating an occupational sun exposure or skin cancer surveillance system for outdoor workers and to understand the key barriers and facilitators to the development of such a system. For the design of a successful occupational safety and health (OSH) surveillance system five occupational surveillance strategies are summarized: exposure registry, disease registry, disease screening/medical surveillance, sentinel event surveillance, and disease surveillance via data linkage. Ten key considerations are identified, including identifying a clear goal, a defined target population and stakeholder involvement, five critical barriers are highlighted including underreporting and funding, and five vital facilitators are recognized including communication/collaboration and a simple reporting process.

Risk of cutaneous squamous cell carcinoma due to occupational exposure to solar ultraviolet radiation: Protocol for a systematic review and meta-analysis.

Solar ultraviolet radiation (UVR) is the most significant occupational carcinogenic exposure in terms of the number of workers exposed (i.e., outdoor workers). Consequently, solar UVR-induced skin cancers are among the most common forms of occupational malignancies that are potentially expected globally. This systematic review is registered in PROSPERO (CRD42021295221) and aims to assess the risk of cutaneous squamous cell carcinoma (cSCC) associated to occupational solar UVR exposure. Systematic searches will be performed in three electronic literature databases (PubMed/Medline, EMBASE, and Scopus). Further references will be retrieved by a manual search (e.g., in grey literature databases, internet search engines, and organizational websites). We will include cohort studies and case-control studies. Risk of Bias assessment will be conducted separately for case-control and cohort studies. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) will be used for the certainty of assessment. In case quantitative pooling is not feasible, a narrative synthesis of results will be performed.

Tailored Sun Safety Messages for Outdoor Workers.

Background: Messaging surrounding skin cancer prevention has previously focused on the general public and emphasized how or when activities should be undertaken to reduce solar ultraviolet radiation (UVR) exposure. Generic messages may not be applicable to all settings, and should be tailored to protect unique and/or highly susceptible subpopulations, such as outdoor workers. The primary objective of this study was to develop a set of tailored, practical, harm-reducing sun safety messages that will better support outdoor workers and their employers in reducing the risk of solar UVR exposure and UVR-related occupational illnesses. Methods: We adapted a core set of sun safety messages previously developed for the general population to be more applicable and actionable by outdoor workers and their employers. This study used an integrated knowledge translation approach and a modified Delphi method (which uses a survey-based consensus process) to tailor the established set of sun safety messages for use for outdoor worker populations. Results: The tailored messages were created with a consideration for what is feasible for outdoor workers, and provide users with key facts, recommendations, and tips related to preventing skin cancer, eye damage, and heat stress, specifically when working outdoors. Conclusion: The resulting tailored messages are a set of evidence-based, expert- approved, and stakeholder-workshopped messages that can be used in a variety of work settings as part of an exposure control plan for employers with outdoor workers.

Prevalence and Level of Occupational Exposure to Asbestos in Canada in 2016.

OBJECTIVE: Asbestos use has decreased over time but occupational exposure still exists today due to the presence of asbestos in older buildings. The objective of this study was to update CAREX Canada's prevalence of exposure estimate from 2006 to 2016, and to assess the level of occupational exposure by industry, occupation, province/territory, and sex. METHODS: Estimates by occupation, industry, province/territory, and sex were calculated using labor force data from the 2016 Census of Population and proportions of workers exposed by occupation and industry, which were previously developed for the 2006 estimates and updated here to reflect new knowledge and changes in exposures. Statistics Canada concordance tables were used to account for changes between the 2006 and 2016 job and industry coding systems. Expert assessment was used to qualitatively assign levels of exposure (low, moderate, or high) for each occupation and industry, with consideration of workers' proximity and access to asbestos-containing material, and the condition and content of asbestos. RESULTS: Approximately 235 000 workers are exposed to asbestos on the job in Canada. The majority of Canadian workers exposed to asbestos are male (89%). Only 5% of all exposed workers are in the high-exposure category, while most workers are in the low (49%) or moderate (46%) exposure categories. The construction sector and associated jobs (e.g. carpenters, trades helpers and laborers, electricians) accounted for the majority of exposed workers. CONCLUSIONS: Occupational exposure to asbestos continues to occur in Canada. Updating the prevalence of exposure estimate and adding exposure levels highlights the shift from high to lower-lever exposures associated with asbestos-containing materials remaining in the built environment.

Social factors and behavioural reactions to radon test outcomes underlie differences in radiation exposure dose, independent of household radon level.

Radioactive radon gas inhalation causes lung cancer, and public health strategies have responded by promoting testing and exposure reduction by individuals. However, a better understanding of how radon exposure disparities are driven by psychological and social variables is required. Here, we explored how behavioural factors modified residential radon-related radiation doses incurred by 2390 people who performed a radon test. The average time from first awareness to receiving a radon test outcome was 6.8-25.5 months, depending on behaviour and attitudes. 20.5% displayed radon test urgency that reduced irradiation between awareness and outcome to 1.8 mSv from a typical 3.5 mSv, while 14.8% (more likely to be men) displayed delaying behaviours that increased exposure to 8.0 mSv. Of those with low radon, 45.9% indicated no future testing intention, underscoring the importance of original tests to reliably establish risk. Among people finding high radon, 38% mitigated quickly, 29% reported economic impediments, and 33% displayed delaying behaviours. Economic barriers and delaying behaviours resulted in 8.4 mSv/year or 10.3 mSv/year long term excess exposure, respectively, increasing lifetime risk of lung cancer by ~ 30-40%. Excess radiation doses incurred from behaviour were independent of household radon level, highlighting the strong influence of psychological and socioeconomic factors on radon exposure and lung cancer risks.

Perspective: Young Workers at Higher Risk for Carcinogen Exposures.

Young workers, those under the age of 25, are considered a vulnerable working population, primarily due to their increased risk of injury. In this study we investigate if young workers may also be at an increased risk for occupational exposure to carcinogens. Using the 2006 and 2016 Canadian Census of Population and previously obtained CAREX Canada data, this study aimed to identify sectors and occupations that have high proportions of young workers and where potential exists for exposure to known and suspected carcinogens. Key groups where young workers are likely at a higher risk for occupational exposure to carcinogens were identified. Our work shows that young workers in construction, outdoor occupations, and farming are key groups that warrant further investigation. These specific groups are highlighted because of the large number of young workers employed in these sectors/situations, the high number of possible carcinogen exposures, and the potential for higher risk behavior patterns that typically occur in these types of jobs. While there is no data available to develop carcinogen exposure estimates specific to young workers, it is our perspective that young workers are likely at a higher risk for occupational exposure to carcinogens. Our findings identify opportunities to improve the occupational health and safety for this vulnerable population, particularly for young construction workers, farm workers, and outdoor workers.

COVID-19 and Vitamin D Misinformation on YouTube: Content Analysis.

Background: The "infodemic" accompanying the SARS-CoV-2 virus pandemic has the potential to increase avoidable spread as well as engagement in risky health behaviors. Although social media platforms, such as YouTube, can be an inexpensive and effective method of sharing accurate health information, inaccurate and misleading information shared on YouTube can be dangerous for viewers. The confusing nature of data and claims surrounding the benefits of vitamin D, particularly in the prevention or cure of COVID-19, influences both viewers and the general "immune boosting" commercial interest. Objective: The aim of this study was to ascertain how information on vitamin D and COVID-19 was presented on YouTube in 2020. Methods: YouTube video results for the search terms "COVID," "coronavirus," and "vitamin D" were collected and analyzed for content themes and deemed useful or misleading based on the accuracy or inaccuracy of the content. Qualitative content analysis and simple statistical analysis were used to determine the prevalence and frequency of concerning content, such as confusing correlation with causation regarding vitamin D benefits. Results: In total, 77 videos with a combined 10,225,763 views (at the time of data collection) were included in the analysis, with over three-quarters of them containing misleading content about COVID-19 and vitamin D. In addition, 45 (58%) of the 77 videos confused the relationship between vitamin D and COVID-19, with 46 (85%) of 54 videos stating that vitamin D has preventative or curative abilities. The major contributors to these videos were medical professionals with YouTube accounts. Vitamin D recommendations that do not align with the current literature were frequently suggested, including taking supplementation higher than the recommended safe dosage or seeking intentional solar UV radiation exposure. Conclusions: The spread of misinformation is particularly alarming when spread by medical professionals, and existing data suggesting vitamin D has immune-boosting abilities can add to viewer confusion or mistrust in health information. Further, the suggestions made in the videos may increase the risks of other poor health outcomes, such as skin cancer from solar UV radiation.

Diesel Engine Exhaust Exposure in the Ontario Civil Infrastructure Construction Industry.

OBJECTIVES: Diesel engine exhaust (DEE) is a known lung carcinogen and a common occupational exposure in Canada. The use of diesel-powered equipment in the construction industry is particularly widespread, but little is known about DEE exposures in this work setting. The objective of this study was to determine exposure levels and identify and characterize key determinants of DEE exposure at construction sites in Ontario. METHODS: Elemental carbon (EC, a surrogate of DEE exposure) measurements were collected at seven civil infrastructure construction worksites and one trades training facility in Ontario using NIOSH method 5040. Full-shift personal air samples were collected using a constant-flow pump and SKC aluminium cyclone with quartz fibre filters in a 37-mm cassette. Exposures were compared with published health-based limits, including the Dutch Expert Committee on Occupational Safety (DECOS) limit (1.03 µg m-3 respirable EC) and the Finnish Institute of Occupational Health (FIOH) recommendation (5 µg m-3 respirable EC). Mixed-effects linear regression was used to identify determinants of EC exposure. RESULTS: In total, 149 EC samples were collected, ranging from <0.25 to 52.58 µg m-3 with a geometric mean (GM) of 3.71 µg m-3 [geometric standard deviation (GSD) = 3.32]. Overall, 41.6% of samples exceeded the FIOH limit, mostly within underground worksites (93.5%), and 90.6% exceeded the DECOS limit. Underground workers (GM = 13.20 µg m-3, GSD = 1.83) had exposures approximately four times higher than below grade workers (GM = 3.56 µg m-3, GSD = 1.94) and nine times higher than above ground workers (GM = 1.49 µg m-3, GSD = 1.75). Training facility exposures were similar to above ground workers (GM = 1.86 µg m-3, GSD = 4.12); however, exposures were highly variable. Work setting and enclosed cabins were identified as the key determinants of exposure in the final model (adjusted R2 = 0.72, P < 0.001). The highest DEE exposures were observed in underground workplaces and when using unenclosed cabins. CONCLUSIONS: This study provides data on current DEE exposure in Canadian construction workers. Most exposures were above recommended health-based limits, albeit in other jurisdictions, signifying a need to further reduce DEE levels in construction. These results can inform a hazard reduction strategy including targeted intervention/control measures to reduce DEE exposure and the burden of occupational lung cancer.

Barriers and facilitators for the safe handling of antineoplastic drugs.

INTRODUCTION: Antineoplastic drugs are widely used in the treatment of cancer. However, some are known carcinogens and reproductive toxins, and incidental low-level exposure to workers is a health concern. CAREX Canada estimated that approximately 75,000 Canadians are exposed to antineoplastic drugs in workplace settings. While policies and guidelines on safe handling of antineoplastic drugs are available, evidence suggests that compliance is low. In this paper, we identify barriers and facilitators for safe handling of antineoplastic drugs in workplace settings. METHODS: We utilized a unique method to study public policy which involved compiling policy levers, developing a logic model, conducting a literature review, and contextualizing data through a deliberative process with stakeholders to explore in-depth contextual factors and experiences for the safe handling of antineoplastic drugs. RESULTS: The most common barriers identified in the literature were: poor training (46%), poor safety culture (41%), and inconsistent policies (36%). The most common facilitators were: adequate safety training (41%), leadership support (23%), and consistent policies (21%). Several of these factors are intertwined and while this means one barrier can cause other barriers, it also allows healthcare employers to mitigate these barriers by implementing small but meaningful changes in the workplace. CONCLUSION: The combination of barriers and facilitators identified in our review highlight the importance of creating work environments where safety is a priority for the safe handling of antineoplastic drugs. The results of this study will assist policy makers and managers in identifying gaps and enhancing strategies that reduce occupational exposure to antineoplastic drugs.

Mutational signatures among young-onset testicular cancers.

BACKGROUND: Incidence of testicular cancer is highest among young adults and has been increasing dramatically for men born since 1945. This study aimed to elucidate the factors driving this trend by investigating differences in mutational signatures by age of onset. METHODS: We retrieved somatic variant and clinical data pertaining to 135 testicular tumors from The Cancer Genome Atlas. We compared mutational load, prevalence of specific mutated genes, mutation types, and mutational signatures between age of onset groups (< 30 years, 30-39 years, ≥ 40 years) after adjusting for subtype. A recursively partitioned mixture model was utilized to characterize combinations of signatures among the young-onset cases. RESULTS: Mutational load was significantly higher among older-onset tumors (p < 0.05). There were no highly prevalent driver mutations among young-onset tumors. Mutated genes and types of nucleotide mutations were not significantly different by age group (p > 0.05). Signatures 1, 8 and 29 were more common among young-onset tumors, while signatures 11 and 16 had higher prevalence among older-onset tumors (p < 0.05). Among young-onset tumors, clustering of signatures resulted in four distinct tumor classes. CONCLUSIONS: Signature contributions differ by age with signatures 1, 8 and 29 were more common among younger-onset tumors. While these signatures are connected with endogenous deamination of 5-methylcytosine, late replication errors and chewing tobacco, respectively, additional research is needed to further elucidate the etiology of young-onset testicular cancer. Large studies of mutational signatures among young-onset patients are required to understand epidemiologic trends as well as inform targeted prevention and treatment strategies.

The efficacy of public health information for encouraging radon gas awareness and testing varies by audience age, sex and profession.

Radioactive radon inhalation is a leading cause of lung cancer and underlies an ongoing public health crisis. Radon exposure prevention strategies typically begin by informing populations about health effects, and their initial efficacy is measured by how well and how fast information convinces individuals to test properties. This communication process is rarely individualized, and there is little understanding if messages impact diverse demographics equally. Here, we explored how 2,390 people interested in radon testing differed in their reaction to radon's public health information and their subsequent decision to test. Only 20% were prompted to radon test after 1 encounter with awareness information, while 65% required 2-5 encounters over several months, and 15% needed 6 to > 10 encounters over many years. People who most delayed testing were more likely to be men or involved in engineering, architecture, real estate and/or physical science-related professions. Social pressures were not a major factor influencing radon testing. People who were the least worried about radon health risks were older and/or men, while negative emotional responses to awareness information were reported more by younger people, women and/or parents. This highlights the importance of developing targeted demographic messaging to create effective radon exposure prevention strategies.

Younger North Americans are exposed to more radon gas due to occupancy biases within the residential built environment.

Residential buildings can concentrate radioactive radon gas, exposing occupants to particle radiation that increases lung cancer risk. This has worsened over time in North America, with newer residences containing greater radon. Using data from 18,971 Canadian households, we calculated annual particle radiation dose rates due to long term residential radon exposure, and examined this as a function of occupant demographics. The current particle radiation dose rate to lungs from residential radon in Canada is 4.08 mSv/y from 108.2 Bq/m3, with 23.4% receiving 100-2655 mSv doses that are known to elevate human cancer risk. Notably, residences built in the twenty-first century are occupied by significantly younger people experiencing greater radiation dose rates from radon (mean age of 46 at 5.01 mSv/y), relative to older groups more likely to occupy twentieth century-built properties (mean age of 53 at 3.45-4.22 mSv/y). Newer, higher radon-containing properties are also more likely to have minors, pregnant women and an overall higher number of occupants living there full time. As younger age-of-exposure to radon equates to greater lifetime lung cancer risk, these data reveal a worst case scenario of exposure bias. This is of concern as, if it continues, it forecasts serious future increases in radon-induced lung cancer in younger people.