Canadian Census Health And Environment Cohort Research Articles

Industrial air pollutant emissions and mortality from Alzheimer's disease in Canada

BackgroundThere is increasing interest in the health effects of source-specific air pollution. However, the relationship between industrial air pollutants and Alzheimer's disease has received limited investigation. ObjectivesTo assess associations of industrial fine particulate matter (PM2.5), nitrogen dioxide (NO2), and sulfur dioxide (SO2) exposures with mortality from Alzheimer's disease. MethodsApproximately 3.2 million adults involved in the 2006 Canadian Census Health and Environment Cohort (CanCHEC) were followed from Census day (May 16, 2006) until death or December 31, 2016. Three-year moving-average industrial emissions with a one-year lag were assigned to the participants based on their residential postal codes. The neighborhood emission of each of the three industrial air pollutants for a postal code was estimated by considering weights of the air pollutant emissions from all industries within a 15 km buffer area, distances between the postal code area and the emitters, and percentages of time per year that the postal code area was downwind of the industrial emitters. Cox proportional hazards models were used to compute hazard ratios (HRs) for deaths from Alzheimer's, adjusting for 15 socio-demographic and contextual covariates. Sensitivity analyses were conducted by adjusting for other industrial emissions, greenness, and comorbidity index, individually. ResultsWe identified 4500 deaths due to Alzheimer's disease from 2006 to 2016 for a total of 32,909,200 person-years across the follow-up period. The adjusted HR for mortality from Alzheimer's related to one interquartile range increase in industrial PM2.5, NO2, and SO2 tonnes/meter per year are 1.006 (95% confidence intervals: 1.000-1.011), 0.994 (0.978-1.011), and 0.998 (0.996-1.001), respectively. Similar positive associations between industrial PM2.5 and mortality from Alzheimer's disease were observed, but there were no clear associations for NO2 and SO2 in sensitivity analyses. ConclusionsExposure to industrial PM2.5 increases the risk of mortality from Alzheimer's disease.

The influence of outdoor PM2.5 concentration at workplace on nonaccidental mortality estimates in a Canadian census-based cohort.

Associations between mortality and exposure to ambient air pollution are usually explored using concentrations of residential outdoor fine particulate matter (PM2.5) to estimate individual exposure. Such studies all have an important limitation in that they do not capture data on individual mobility throughout the day to areas where concentrations may be substantially different, leading to possible exposure misclassification. We examine the possible role of outdoor PM2.5 concentrations at work for a large population-based mortality cohort. Using the 2001 Canadian Census Health and Environment Cohort (CanCHEC), we created a time-weighted average that incorporates employment hours worked in the past week and outdoor PM2.5 concentration at work and home. We used a Cox proportional hazard model with a 15-year follow-up (2001 to 2016) to explore whether inclusion of workplace estimates had an impact on hazard ratios for mortality for this cohort. Hazard ratios relying on outdoor PM2.5 concentration at home were not significantly different from those using a time-weighted estimate, for the full cohort, nor for those who commute to a regular workplace. When exploring cohort subgroups according to neighborhood type and commute distance, there was a notable but insignificant change in risk of nonaccidental death for those living in car-oriented neighborhoods, and with commutes greater than 10 km. Risk analyses performed with large cohorts in low-pollution environments do not seem to be biased if relying solely on outdoor PM2.5 concentrations at home to estimate exposure.

Mortality among First Nations people, 2006 to 2016.

First Nations people were reported to have a shorter life expectancy and were more likely than their non-Indigenous counterparts to die prematurely from avoidable causes. Using the 2006 Canadian Census Health and Environment Cohort (CanCHEC), the number and rates of deaths for a 10-year follow-up period for on- and off-reserve First Nations people and the non-Indigenous population were calculated by sex, age and region. According to the 2006 CanCHEC data, First Nations people showed higher age-standardized mortality rates (ASMRs) compared with the non-Indigenous population. On-reserve First Nations people showed higher ASMRs than off-reserve First Nations people. First Nations people's excess mortality, compared with their non-Indigenous counterparts, was caused by deaths from diabetes, heart diseases, chronic liver disease and cirrhosis, unintentional injuries, and intentional injuries (suicide and assault). The mortality differential between First Nations people and the non-Indigenous population was found to be more pronounced among younger age groups. First Nations people's excess mortality can be better understood by examining specific causes for specific population groups, based on age, sex, being on- or off-reserve, and region.

Ambient air pollution and the risk of acute myocardial infarction and stroke: A national cohort study

We used a large national cohort in Canada to assess the incidence of acute myocardial infarction (AMI) and stroke hospitalizations in association with long-term exposure to fine particulate matter (PM2.5), nitrogen dioxide (NO2), and ozone (O3). The study population comprised 2.7 million respondents from the 2006 Canadian Census Health and Environment Cohort (CanCHEC), followed for incident hospitalizations of AMI or stroke between 2006 and 2016. We estimated 10-year moving average estimates of PM2.5, NO2, and O3, annually. We used Cox proportional hazards models to examine the associations adjusting for various covariates. For AMI, each interquartile range (IQR) increase in exposure was found to be associated with a hazard ratio of 1.026 (95% CI: 1.007–1.046) for PM2.5, 1.025 (95% CI: 1.001–1.050) for NO2, and 1.062 (95% CI: 1.041–1.084) for O3, respectively. Similarly, for stroke, an IQR increase in exposure was associated with a hazard ratio of 1.078 (95% CI: 1.052–1.105) for PM2.5, 0.995 (95% CI: 0.965–1.030) for NO2, and 1.055 (95% CI: 1.028–1.082) for O3, respectively. We found consistent evidence of positive associations between long-term exposures to PM2.5, and O3, and to a lesser degree NO2, with incident AMI and stroke hospitalizations.

Urban active living environments and cardiovascular disease mortality: a Canadian national cohort study

BACKGROUND AND AIM: Neighbourhoods conducive to utilitarian walking and active living are associated with higher physical activity and lower cardiovascular risk factors. Most evidence, however, has been drawn from ecological studies. Our aim was to investigate longitudinal associations between neighbourhood walkability and cardiovascular mortality in a large population-based cohort of Canadian adults. METHODS: We analyzed data from the 2001 Canadian Census Health and Environment Cohort (CanCHEC). These data were obtained from the mandatory 2001 long-form census, which includes a random sample of roughly 20% of the Canadian population. Individual-level data from the 2001 census were linked to income tax files to provide annual residential postal codes, while mortality was ascertained by linkage to the Canadian Vital Statistics Death Database between 2001 and 2016. The main exposure was the Canadian Active Living Environments (Can–ALE), a national quintile index that summarizes features of the built environment related to active living and walkability. We restricted our analysis to those 19 years of age and older at baseline who lived in large city areas (population ≥100,000), allowing individual person-years to move in and out of the analytical sample. Cox proportional hazard models were fit to estimate hazard ratios for Can–ALE categories and cardiovascular mortality while adjusting for many individual and contextual covariates. RESULTS:A total of 26,875,875 person-years (53% female) and 266,740 deaths were included in the model. Living in a highly walkable neighbourhood (Can–ALE 5 [high] vs 1 [low]) was significantly associated with a 6% reduced hazard of cardiovascular mortality (aHR: 0.94, 95%CI: 0.90, 0.98), 11% reduced hazard of cerebrovascular mortality (aHR: 0.89, 95%CI: 0.81, 0.98), and a 7% reduced hazard of ischemic heart disease mortality (aHR: 0.93, 95%CI: 0.88, 0.99). CONCLUSIONS:Living in an urban neighbourhood or community supportive of utilitarian walking and active living may contribute to lower mortality from cardiovascular disease in adults. KEYWORDS: Built environment, walkability, cardiovascular diseases, mortality

Long-term Testis Cancer Survivors in Canada—Mortality Risks in a Large Population-based Cohort

BackgroundTestis cancer (TC) patients are young with excellent cancer prognosis. Hence, the risk of late-onset treatment-related morbidity and mortality is of concern due to longer survival after treatment. ObjectiveWe set to characterize long-term survival of TC patients through a Canadian population dataset. Design, setting, and participantsWe used a population-based dataset, the Canadian Census Health and Environment Cohort (CanCHEC), to identify individuals diagnosed with TC between 1991 and 2010. We compared them with all other male individuals without TC. Outcome measurements and statistical analysisThe primary outcome was mortality due to cardiovascular disease (CVD) or nontesticular malignancy. Mann-Whitney or chi-square test was used where applicable. Data were analyzed using a Cox proportional hazard model with and without matching. Results and limitationsWe identified 1950 individuals with TC. We compared them with 1 300 295 men with no TC. There were 335 deaths in the study group during the study period (17.2%) with a mean follow-up of 19.6 yr. TC patients were at increased risk of death from secondary malignancies (hazard ratio [HR] 1.63, 95% confidence interval [CI] 1.39–1.91; p < 0.0001) with specific risks for hematologic neoplasms (HR 3.86, 95% CI 2.78–5.37; p < 0.001) and other malignancies (HR 2.41, 95% CI 1.76–3.29; p < 0.001). Gastrointestinal, hematologic, and respiratory toxicities were the most common secondary malignancies leading to death. When stratified according to histology, nonseminoma (NS) patients were at significantly increased risk of death from CVD (HR 2.03, 95% CI 1.27–3.25; p = 0.0032). Individuals with seminoma were at increased risk of death from other nontestis neoplasms (HR 1.46, 95% CI 1.17–1.82; p = 0.0007), specifically hematologic neoplasms (HR 2.09, 95% CI 1.18–3.72; p = 0.0118). ConclusionsNS patients are at increased risk of CVD-related death, whereas seminoma patients are at increased risk of death from non–testis-related malignancies. Patient summaryWe report long-term mortality following diagnosis of testis cancer. Nonseminoma patients have an increased risk of death from cardiovascular disease, while seminoma patients have an increased risk of death from secondary malignancies.

Geographic variation in preventable hospitalisations across Canada: a cross-sectional study

ObjectiveThe objective of this study is to examine the magnitude and pattern of small-area geographic variation in rates of preventable hospitalisations for ambulatory care-sensitive conditions (ACSC) across Canada (excluding Québec).Design...

Use of a Canadian Population-Based Surveillance Cohort to Test Relationships Between Shift Work and Breast, Ovarian, and Prostate Cancer.

Shift work with circadian disruption is a suspected human carcinogen. Additional population-representative human studies are needed and large population-based linkage cohorts have been explored as an option for surveillance shift work and cancer risk. This study uses a surveillance linkage cohort and job-exposure matrix to test relationships. We estimated associations between shift work and breast, ovarian, and prostate cancer using the population-based Canadian Census Health and Environment Cohort (CanCHEC), linking the 1991 Canadian census to national cancer registry and mortality databases. Prevalence estimates from population labour survey data were used to estimate and assign probability of night, rotating, or evening shifts by occupation and industry. Cohort members were assigned to high (>50%), medium (>25 to 50%), low (>5 to 25%), or no (<5%) probability of exposure categories. Cox proportional hazards modelling was used to estimate associations between shift work exposure and incidence of prostate cancer in men and ovarian and breast cancer in women. The cohort included 1 098 935 men and 939 520 women. Hazard ratios (HRs) indicated null or inverse relationships comparing high probability to no exposure for prostate cancer: HR = 0.96, 95% confidence interval (CI) = 0.91-1.02; breast cancer: HR = 0.94, 95% CI = 0.90-0.99; and ovarian cancer: HR = 0.99, 95% CI = 0.87-1.13. This study showed inverse and null associations between shift work exposure and incidence of prostate, breast, or ovarian cancer. However, we explore limitations of a surveillance cohort, including a possible healthy worker survivor effect and the possibility that this relationship may require the nuanced exposure detail in primary collection studies to be measurable.

MAPLE

S13: How Low Should We Go? New Health Research on Low-level Ambient Air Pollution, Beatrix Theater, August 28, 2019, 1:30 PM - 3:00 PM Background/Aims Fine particulate matter (PM2.5) is associated with mortality, however the range of applicable concentrations is unknown. We applied novel satellite-based estimates of PM2.5 exposure to large population-based cohorts, and characterized the shape of the mortality relationship, with emphasis on the low concentrations (<12 µg/m3) observed throughout Canada. Methods Annual satellite-based PM2.5 exposure estimates were developed at 1 km resolution across Canada for 1998-2016 and back-casted to 1981 using remote sensing, chemical transport models and ground monitoring data. Exposures were estimated for ~8.5 million subjects in three Canadian Census Health and Environment Cohort (CanCHEC) cohorts, and 540,900 Canadian Community Health Survey (CCHS) participants, based on residential histories derived from annual tax records. Mortality was linked until 2016. Sensitivity analyses evaluated adjustment for (individual/contextual/geographic) covariates and gaseous (NO2, ozone) co-pollutants; exposure time windows and spatial scale. Estimates were evaluated across strata of age, sex and immigrant status and the shape of the PM2.5 and mortality association was examined with the Shape Constrained Health Impact Function (SCHIF). Results Satellite-based PM2.5 estimates were low (mean 3-year averages of 7.4μg/m3 and 5.9 µg/m3 in CanCHEC and CCHS, respectively) and highly correlated with ground monitors (R2 = 0.82, RMSE=1.5 µg/m3). In final adjusted models non-accidental mortality hazard ratios (HR) per 10µg/m3 change in PM2.5 were 1.04 (95% CI: 1.04-1.05) in CanCHEC and 1.11 (95% CI 1.04-1.18) in CCHS. In CanCHEC the SCHIF predicted a sublinear concentration-mortality curve with little increased risk below 5 g/m3, and monotonically increased HRs above this concentration. In CCHS we estimated a supra-linear relationship to concentrations below 2µg/m3. HRs were larger for females, younger ages and non-immigrants and attenuated by gaseous pollutants. Conclusions In large population-based cohorts exposed to low levels of air pollution with extended follow-up we observed associations between PM2.5 and non-accidental mortality for concentrations as low as 5 µg/m3.

Exposure to traffic and mortality risk in the 1991–2011 Canadian Census Health and Environment Cohort (CanCHEC)

There is evidence that local traffic density and living near major roads can adversely affect health outcomes. We aimed to assess the relationship between local road length, proximity to primary highways, and cause-specific mortality in the 1991 Canadian Census Health and Environment Cohort (CanCHEC). In this long-term study of 2.6 million people, based on completion of the long-form census in 1991 and followed until 2011, we used annual residential addresses to determine the total length of local roads within 200 m of postal code representative points and the postal code's distance to primary highways. The association between exposure to traffic and cause-specific non-accidental mortality was estimated using Cox proportional hazards models, adjusting for individual covariates and contextual factors, including census division-level proportion in high school, the percentage of recent immigrants, and neighborhood income. We performed sensitivity analyses, including adjustment for exposure to PM2.5, NO2, or O3, restricting to subjects in core urban areas, and spatial variation by climatic zone. The hazard ratio (HR) for all non-accidental mortality associated with an interquartile increase in length of local roads was 1.05 (95% CI 1.04, 1.05), while for an interquartile range increase in proximity to primary highways, the HR was 1.03 (95% CI 1.02, 1.04). HRs by traffic quartile increased with increasing lengths of local roads, as well as with closer proximity to primary highways, for all mortality causes. The associations were stronger within subjects' resident in urban core areas, attenuated by adjustment for PM2.5, and HRs showed limited spatial variation by climatic zone. In the CanCHEC cohort, exposure to higher road density and proximity to major traffic roads was associated with increased mortality risk from cerebrovascular and cardiovascular disease, ischemic heart disease, COPD, respiratory disease, and lung cancer, with unclear results for diabetes.

Diabetes Status and Susceptibility to the Effects of PM2.5 Exposure on Cardiovascular Mortality in a National Canadian Cohort.

Diabetes is infrequently coded as the primary cause of death but may contribute to cardiovascular disease (CVD) mortality in response to fine particulate matter (PM2.5) exposure. We analyzed all contributing causes of death to examine susceptibility of diabetics to CVD mortality from long-term exposure. We linked a subset of the 2001 Canadian Census Health and Environment Cohort (CanCHEC) with 10 years of follow-up to all causes of death listed on death certificates. We used survival models to examine the association between CVD deaths (n = 123,500) and exposure to PM2.5 among deaths that co-occurred with diabetes (n = 20,600) on the death certificate. More detailed information on behavioral covariates and diabetes status at baseline available in the Canadian Community Health Survey (CCHS)-mortality cohort (n = 12,400 CVD deaths, with 2,800 diabetes deaths) complemented the CanCHEC analysis. Among CanCHEC subjects, comention of diabetes on the death certificate increased the magnitude of association between CVD mortality and PM2.5 (HR = 1.51 [1.39-1.65] per 10 μg/m) versus all CVD deaths (HR = 1.25 [1.21-1.29]) or CVD deaths without diabetes (HR = 1.20 [1.16-1.25]). Among CCHS subjects, diabetics who used insulin or medication (included as proxies for severity) had higher HR estimates for CVD deaths from PM2.5 (HR = 1.51 [1.08-2.12]) relative to the CVD death estimate for all respondents (HR = 1.31 [1.16-1.47]). Mention of diabetes on the death certificate resulted in higher magnitude associations between PM2.5 and CVD mortality, specifically among those who manage their diabetes with insulin or medication. Analyses restricted to the primary cause of death likely underestimate the role of diabetes in air pollution-related mortality. See video abstract at, http://links.lww.com/EDE/B408.

Reflections on the Canadian CanCHEC Cohort: Where We've Been and Where We Are Going

The Canadian Census Health and Environment Cohort (CanCHEC) was developed to advance the scientific knowledge about the impacts of prolonged exposure to low-levels of ambient air pollution. Initially, this large-scale cohort consisted of the 20% of Canadian households who were mandated to complete the more detailed long-form census in 1991. Dr. Burnett played a prominent role in the development of the cohort which has since been extended to include those who completed the long-form census in 1996, 2001, and 2006. Probabilistic record linkage of these cohorts were undertaken to link these individuals to Canadian income tax, mortality and cancer registry data. Linkages to the tax databases allowed for the determination of place of residence on an annual basis. Combined, these cohorts include nearly 13 million Canadians (37%) and approximately 1.7 million deaths identified during follow-up. Estimates of ambient air pollution concentrations have been assigned to cohort subjects based on their residential postal codes using a variety of methods including fixed-site monitoring, land use regression, and remote sensing techniques. Analyses of the CanCHEC have provided insights on how long term-exposure to low levels of ambient pollution is associated with cause-specific mortality. This presentation will highlight the contributions of Dr. Burnett with respect to the major research findings for air pollution that have been obtained from this cohort. These include estimates for associations between ambient air pollution concentration and mortality with respect to: (i) the shape of the exposure-response curve, (ii) oxidative burden of fine particulate matter, (iii) methods to indirectly adjust for the impacts of missing covariates, and (iv) methods to account for within- and between-city variations in risk. Lastly, this presentation will highlight ongoing and future research activities using the CanCHEC.

Traffic Density and Mortality Risk in the 1991 Canadian Census Health and Environment Cohort (CanCHEC)

Background: There is evidence that local traffic density and living near major roads can adversely affect health outcomes. We aimed to assess the relationship between local road length, proximity to primary highways, and cause-specific mortality in the 1991 Canadian Census Health and Environment Cohort (CanCHEC).Methods: In this long-term study of 2.6 million people, based on completion of the long-form Census in 1991 and followed up until 2011, we used annual residential addresses to determine the total length of local roads within 200 m of centroid of postal codes, and the subject&amp;#8217;s distance to primary highways. The association between exposure to traffic and cause-specific mortality was estimated using Cox proportional hazards models, adjusting for individual covariates and contextual factors, including census division-level proportion in high school, the percentage of recent immigrants, and neighborhood income. We performed sensitivity analyses, including adjustment for exposure to PM2.5, restricted to subjects in core urban areas, and spatial variation by climatic zone.Results The hazard ratio (HR) for all non-accidental mortality associated with an interquartile increase in length of local roads was 1.05 (95% CI 1.04, 1.05); and for an interquartile range increase in proximity to primary highways, 1.03 (95% CI 1.02, 1.04). However, HRs by traffic quartile increased with increasing lengths of local roads, or closer proximity to primary highways, for all mortality causes. The associations were stronger in subject residing in urban core areas, attenuated by adjustment for PM2.5, and HRs showed limited spatial variation by climatic zone.Conclusion: In the CanCHEC cohort, exposure to greater road density and proximity to major traffic roads were associated with increased mortality risk from cerebrovascular and cardiovascular disease, ischemic heart disease, COPD, respiratory disease, lung cancer, and with unclear results for diabetes.

Disease Assimilation: The Loss of the Healthy Immigrant Advantage over Time with Exposure to Fine Particulate Matter

Background. Immigrants make up 20 percent of the Canadian population, yet recent immigrants (&amp;lt; 20 years in Canada) are often excluded from air pollution mortality analyses to reduce possible confounding. Thus, little is known about the mortality impacts of fine particulate air pollution (PM2.5) on this population and how it changes over time.Methods. We used the 2001 Canadian Census Health and Environment Cohort (CanCHEC), a longitudinal cohort of 3.5 million subjects of which 764,000 were immigrants linked to annual mobility and PM2.5 concentration from 1994 to 2011. Exposures were assigned as a 3 and 8-year mean prior to the follow-up year. Income tax files were used to account for residential mobility among respondents using postal codes, with probabilistic imputation used for missing postal codes in the tax data. We used Cox survival models to determine hazard ratios (HRs) for cause-specific mortality, and assessed year of immigration and country of origin.Results. In partially adjusted models (individual socioeconomic variables, airshed, and population centre size) stratified by age and sex, preliminary analyses of only immigrants compared the full cohort with immigrants as a covariate showed slightly lower HR estimates for cardiovascular (CVD) mortality: HR&amp;#61;1.07 (95% CI: 1.03 to 1.12) vs. HR&amp;#61;1.08 (95% CI: 1.06 to 1.10); and ischemic heart disease (IHD) mortality: (HR&amp;#61;1.09; 95% CI: 1.02 to 1.15) vs. (HR&amp;#61;1.11; 95% CI: 1.08 to 1.14) per 5 &amp;#956;g/m3 increase in PM2.5 concentration respectively. The HR estimates of CVD, IHD and other chronic diseases increased with increased time in Canada among immigrants. Interaction models with country of origin and sensitivity analyses are on-going.Conclusions. Preliminary analyses suggest that air pollution is an equal opportunity risk factor; however, the relationship between immigration, health and air pollution is complex, partly due to unknown previous exposures along with a diverse and dynamic country of origin population.

Canadian trends in the social determinants of health inequalities, a census-mortality linkage approach

IntroductionMortality inequalities by income and education levels have historically been estimated using an area-based approach in Canada. Although useful in measuring socioeconomic inequalities overtime, this method underestimates the level of inequality and only allows the examination of a single dimension at a time.&#x0D; Objectives and ApproachTo create a series of census linked datasets that allowed for the examination of health inequalities across different socioeconomic dimensions. Specifically, five census cycles (beginning with the 1991 Census) were probabilistically and deterministically linked to different health outcomes (mortality, cancer, hospitalization) to create the Canadian Census Health and Environment Cohort (CanCHEC). Each dataset was created using a similar methodological approach which allowed for the measurement of these health inequalities over time. Mortality inequalities by both income and education level (including multidimensional) for all causes and cause-specific groups were examined.&#x0D; ResultsFive census linked datasets were constructed that followed mortality for a period of up to 20 years. The 1991 CanCHEC includes 2.6 million adults, the 1996 and 2001 CanCHECs include 3.5 million adults respectively, and the 2006 and 2011 CanCHECs include 5.9 and 6.5 million people respectively. Findings revealed a stair-stepped gradient in all-cause and cause-specific mortality by educational attainment and income quintile across each time period. The lowest mortality rates were among the university educated and richest income quintile and highest mortality rates among those with less than high school graduation and the poorest income quintile. The gradient differed by cause of death groupings. Over the 25-year time period, the mortality gradient trend varied by socioeconomic dimension and cause of death.&#x0D; Conclusion/ImplicationsThese data show clear mortality inequalities by socioeconomic position across the different time periods. These linked datasets can help advance knowledge in understanding health inequalities in Canada as well as provide a tool for on-going surveillance of health inequalities by different socioeconomic dimensions.

Prostate cancer surveillance by occupation and industry: the Canadian Census Health and Environment Cohort (CanCHEC).

As there are no well‐established modifiable risk factors for prostate cancer, further evidence is needed on possible factors such as occupation. Our study uses one of the largest Canadian worker cohorts to examine occupation, industry, and prostate cancer and to assess patterns of prostate cancer rates. The Canadian Census Health and Environment Cohort (CanCHEC) was established by linking the 1991 Canadian Census Cohort to the Canadian Cancer Database (1969–2010), Canadian Mortality Database (1991–2011), and Tax Summary Files (1981–2011). A total of 37,695 prostate cancer cases were identified in men aged 25–74 based on age at diagnosis. Cox proportional hazards models were used to estimate hazards ratios and 95% confidence intervals. In men aged 25–74 years, elevated risks were observed in the following occupations: senior management (HR = 1.12, 95% CI: 1.04–1.20); office and administration (HR = 1.19, 95% CI: 1.11–1.27); finance services (HR = 1.09, 95% CI: 1.04–1.14); education (HR = 1.05, 95% CI: 1.00–1.11); agriculture and farm management (HR = 1.12, 95% CI: 1.06–1.17); farm work (HR = 1.11, 95% CI: 1.01–1.21); construction managers (HR = 1.07, 95% CI: 1.01–1.14); firefighting (HR = 1.17, 95% CI: 1.01–1.36); and police work (HR = 1.22, 95% CI: 1.09–1.36). Decreased risks were observed across other construction and transportation occupations. Results by industry were consistent with occupation results. Associations were identified for white‐collar, agriculture, protective services, construction, and transportation occupations. These findings emphasize the need for further study of job‐related exposures and the potential influence of nonoccupational factors such as screening practices.

Occupation and Risk of Bladder Cancer: A Population Level Comparison of Nordic Countries and Canada

Background/Aim: Associations with bladder cancer have been observed for more than 40 occupations. While some findings have been consistent, others have been inconsistent or limited. Outside of the Nordic countries, only few countries have directly linked information on cancer and census data. The aim of the study was to compare occupational variation of the risk of bladder cancer in the Nordic countries and Canada. Methods: In the Nordic occupational cancer study (NOCCA) 73,653 bladder cancer cases were observed during follow up of 141.6 million person years. In the Canadian Census Health and Environment Cohort (CanCHEC) 8,170 cases were observed during 36.7 million person years of follow up. Standardized incidence ratios (SIR) with 95% confidence intervals (CI) were estimated for 53 occupations in the NOCCA cohort and hazard ratios (HR) with 95% CIs were estimated for 42 occupations in the CanCHEC cohort. Results: Elevated risks of bladder cancer were observed among hairdressers, printers, sales workers, plumbers, painters, miners, and laundry workers. Teachers and agricultural workers had reduced risk of bladder cancer in both cohorts. Chimney sweeps, tobacco workers and waiters had about 1.5-fold risk in the Nordic countries; no risk estimates for these categories were given from the CanCHEC cohort. Conclusions: We observed different occupational patterns in risk of bladder cancer in Nordic countries and Canada. The only occupation with similarly increased risk was observed among sales workers. Differences in smoking across occupational groups may explain some, but not all, of this variation.

Associations between long-term PM2.5 and ozone exposure and mortality in the Canadian Census Health and Environment Cohort (CANCHEC), by spatial synoptic classification zone

Studies suggest that long-term chronic exposure to fine particulate matter air pollution can increase lung cancer mortality. We analyzed the association between long term PM2.5 and ozone exposure and mortality due to lung cancer, ischemic heart disease, and chronic obstructive pulmonary disease, accounting for geographic location, socioeconomic status, and residential mobility. Subjects in the 1991 Canadian Census Health and Environment Cohort (CanCHEC) were followed for 20years, and assigned to regions across Canada based on spatial synoptic classification weather types. Hazard ratios (HR) for mortality, were related to PM2.5 and ozone using Cox proportional hazards survival models, adjusting for socioeconomic characteristics and individual confounders. An increase of 10μg/m3 in long term PM2.5 exposure resulted in an HR for lung cancer mortality of 1.26 (95% CI 1.04, 1.53); the inclusion in the model of SSC zone as a stratum increased the risk estimate to HR 1.29 (95% CI 1.06, 1.57). After adjusting for ozone, HRs increased to 1.49 (95% CI 1.23, 1.88), and HR 1.54 (95% CI 1.27, 1.87), with and without zone as a model stratum. HRs for ischemic heart disease fell from 1.25 (95% CI 1.21, 1.29) for exposure to PM2.5, to 1.13 (95% CI 1.08, 1.19) when PM2.5 was adjusted for ozone. For COPD, the 95% confidence limits included 1.0 when climate zone was included in the model. HRs for all causes of death showed spatial differences when compared to zone 3, the most populated climate zone. Exposure to PM2.5 was related to an increased risk of mortality from lung cancer, and both ozone and PM2.5 exposure were related to risk of mortality from ischemic heart disease, and the risk varied spatially by climate zone.

Occupational variation in incidence of bladder cancer: a comparison of population-representative cohorts from Nordic countries and Canada

ObjectivesThe objective of this study was to compare occupational variation of the risk of bladder cancer in the Nordic countries and Canada.MethodsIn the Nordic Occupational Cancer study (NOCCA), 73 653...

Sedentary work and the risks of colon and rectal cancer by anatomical sub-site in the Canadian census health and environment cohort (CanCHEC)

BackgroundSedentary behaviour is a potential risk factor for colorectal cancer. We examined the association between sedentary work, based on body position, and colorectal cancer risk in Canadians. MethodsA working body position category (a. sitting; b. standing and walking; c. sitting, standing, and walking; d. other) was assigned to occupations reported by 1991 Canadian Census respondents based on national occupational counselling guidelines. Adjusted hazard ratios (HRs) and 95% confidence intervals (CI) were estimated for cancers of the colon (overall, proximal, and distal) and rectum in men and women newly diagnosed from 1992 to 2010. ResultsCompared to “sitting” jobs, men in occupations with “other” (non-sitting, −standing, or −walking) body positions had a weakly significant reduced colon cancer risk (HR=0.93, 95% CI: 0.89, 0.98) primarily attributed to protection at the distal site (HR=0.90, 95% CI: 0.84, 0.97). Men in “standing and walking” and “sitting, standing, and walking” jobs did not have significantly reduced colon cancer risks. No effects were observed for rectal cancer in men or colon and rectal cancer in women. ConclusionThe two significant findings of this analysis should be followed-up in further investigations with additional information on potential confounders. Null findings for rectal cancer were consistent with other studies.