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.

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.

Sun Protection Use at Work and Leisure by Outdoor Workers in Alberta, Canada.

OBJECTIVE: To assess the prevalence and determinants of sun protection behaviours among outdoors workers at work and leisure in Alberta, Canada. METHODS: We collected outdoor workers' demographics, skin cancer risk factors, job information, and sun habits at work and leisure using self-completed questionnaires. For both settings, we compared use of specific behaviours and modelled determinants of sun protection behaviour scores. RESULTS: At work, wearing a sleeved shirt (81% often/always) and hat (73%) were most prevalent, while seeking shade (12%) and applying sunscreen (36%) were least prevalent. Workers had higher sun protection scores at work than leisure. Hours spent outdoors was a strong determinant for both models. Additional leisure model predictors were eye colour, sex, skin type, and job group. CONCLUSIONS: Differences in behaviours across settings were observed and should be considered when developing solar UVR exposure reduction initiatives.

Estimating Exposure to Three Commonly Used, Potentially Carcinogenic Pesticides (Chlorolathonil, 2,4-D, and Glyphosate) Among Agricultural Workers in Canada.

OBJECTIVES: Certain pesticides have been associated with adverse health outcomes including cancer and reproductive harms. However, little is known about the prevalence of occupational pesticide exposure among agricultural workers in Canada. The purpose of this study was to estimate the prevalence and likelihood of occupational exposure to pesticides in Canada's agricultural industry, using three commonly used, potentially carcinogenic pesticides [chlorothalonil, 2,4-dichlorophenoxyacetic acid (2,4-D), and glyphosate] as an example. METHODS: Estimates were calculated using the Canadian Census of Population and the Census of Agriculture. The number of workers and the proportion of farms applying 'herbicides' or 'fungicides' by farm type was estimated using survey data from the Census of Agriculture. These values were multiplied to yield the potential number of workers at risk of exposure. Likelihood of exposure (i.e. exposed, probably exposed, and possibly exposed) was then qualitatively assigned using information on crop type, primary expected tasks, crop production practices, and residue transfer data. Additional agricultural workers who are at risk of exposure but not captured by the Census of Agriculture were identified using the 2016 Census of Population. RESULTS: An estimated range of 37 700-55 800 workers (11-13% of agricultural workers) were exposed to glyphosate in Canada while 30 800-43 600 workers (9-11%) and 9000-14 100 (2.9-3.2%) were exposed to 2,4-D and chlorothalonil, respectively. Approximately 70-75% of workers at risk of exposure were considered probably or possibly exposed to any of the pesticides. Glyphosate exposure was most common among workers in oilseed (29% of oilseed farm workers exposed) and dry pea/bean farms (28%), along with those providing support activities for farms (31%). 2,4-D exposure was most common in corn (28%), other grain (28%), and soybean farms (27%), while chlorothalonil exposure was more likely among greenhouse, nursery, and floriculture workers (42%), workers on farms (28%, for occupations not captured by the Census of Agriculture, specifically), and those providing support activities for farms (20%). Regional variations broadly reflected differences in farm types by province. CONCLUSIONS: This study estimated the prevalence of occupational exposure to three pesticides in Canada. Seasonal and temporary agricultural workers, which were captured by the Census of Agriculture, contributed to many additionally exposed workers. A large percent of the workers who were considered at risk of exposure were considered probably or possibly exposed, indicating a need for enhanced data collection and availability on pesticide use data in Canada. The study's methods can be applied to estimate workers' exposures to other pesticides within the agricultural industry.

Solar ultraviolet radiation exposure among outdoor workers in Alberta, Canada.

BACKGROUND: Outdoor workers are at risk of prolonged and high solar ultraviolet radiation (UVR) exposure, which is known to cause skin cancer. The objectives of this study were to characterize the UVR exposure levels of outdoor workers in Alberta, Canada, and to investigate what factors may contribute to their exposure. METHODS: This study collected objective solar UVR measurements from outdoor workers primarily in Alberta during the summer of 2019. Workers were recruited via the management or health and safety teams from building trade unions and employers. Calibrated, electronic UVR dosimeters were worn by workers on their hardhats, wrists, or lapels for five working days. Data on workers' demographics, jobs, sun protection behaviors, and personal risk factors were collected using questionnaires, and meteorological data for each sampling day were noted. Mean daily exposure measured as the standard erythemal dose (SED) was calculated and compared to the international occupational exposure limit guideline (1.3 SED). Marginal models were developed to evaluate potential determinants of occupational solar UVR exposure. RESULTS: In total, 883 measurements were collected from 179 workers. On average, workerswere exposed to 1.93 SED (range: 0.03-16.63 SED) per day. Just under half of workers (45%) were exposed to levels exceeding the international exposure limit guideline. In the bivariate analyses, landscape and maintenance workers, as well as trade and recreation workers, had the highest levels of exposure (average: 2.64 and 1.84 SED, respectively). Regional variations were observed, with the "other" cities/regions (outside of Edmonton and Calgary) experiencing the highest average levels (2.60 SED). Workers who placed the dosimeters on their hardhats experienced higher levels compared to the other groups. Exposure was highest on sunny and mixed days. Education, trade, city, dosimeter placement, forecast, hair colour, and number of hours outside were included in the final exposure model, of which trade, dosimeter placement, forecast, and number of hours outside at work were statistically significant. CONCLUSIONS: Exposure to elevated solar UVR levels is common among outdoor workers in Alberta. The study findings can help inform future monitoring studies and exposure reduction initiatives aimed at protecting workers.

Using geographic information systems to estimate potential pesticide exposure at the population level in Canada.

Residents in close proximity to agricultural land are at risk of higher pesticide exposures. The purpose of this study was to generate national population-level exposure estimates for Canada for three commonly applied pesticides that are suspected carcinogens (2,4-dichlorophenoxyacetic acid (2,4-D), glyphosate and chlorothalonil). Using geographic information systems, pesticide exposure was estimated for every - census subdivision (CSD) in Canada (n = 5054) by combining raster-based surfaces for the distribution of crops with average crop-specific pesticide application rates data. Analyses examined all identified crops in combination with different pesticide application rates to obtain a cumulative potential total exposure. Specifically, the number of acres of particular crops were calculated for each CSD and then multiplied by the average pesticide application rates data, summed across crops, and combined with population data by CSD to provide a potential pesticide exposure estimate for each CSD. Results demonstrate that the population exposure varies greatly depending on agricultural production by CSD region. For example, in Ontario, the 2,4-D application rate was an average of 361 kg/km2, while in Saskatchewan, which primarily grows field/cereal crops, 2,4-D application rates were much higher (3810 kg/km2). The highest potential exposures to all three pesticides were in the prairie provinces (Alberta, Saskatchewan, Manitoba) along with Prince Edward Island, Southern Quebec and British Columbia. This work can be used in conjunction with other exposure assessment approaches to better understand overall pesticide exposure among Canada's general population.

Population-level estimates of workplace exposure to secondhand smoke in Canada.

OBJECTIVES: Secondhand smoke (SHS) is a known lung carcinogen that is also associated with cardiovascular disease and premature death. An important source of exposure to SHS is the workplace. In the past, efforts have been made to reduce workplace SHS exposure across Canada, with corresponding benefits to public health. This study estimated the number of workers exposed to SHS in Canada in 2006 and 2016 and their level of exposure. METHODS: The proportion of workers exposed to SHS and the proportion of workers reporting specific workplace smoking restrictions by occupation and province, acquired from the 2007-2009 and 2010-2012 Canadian Tobacco Use Monitoring Surveys, were applied to 2006 and 2016 Canadian census data to estimate population-level exposure. Workers were assigned to exposure levels (possible, moderate, high) using workplace smoking restrictions. Only moderately and highly exposed workers were considered exposed. RESULTS: The number of exposed workers decreased by 20% from 520,000 in 2006 to 418,000 in 2016. Workers were equally split between moderate and high exposure groups. Trades, transport and equipment operators, and workers in primary industry had the highest rates of overall exposure. The proportion of workers exposed varied by province, with the lowest rates in Ontario (approximately 2% in both years), and the highest in Saskatchewan in 2006 (6%) and Newfoundland in 2016 (4%). CONCLUSION: Workplace SHS exposure persists. The findings can help prioritize high-risk groups for interventions and inform studies of the burden of occupational disease. Further characterization of exposure is needed to better inform enforcement and prevention.