Dissanayake A, Dupuis A, Burton CL, Soreni N, Peters PA, Gajaria A, Arnold P, Crosbie J, & R Schachar. (2024) “Racial/Ethnic Disparities in Youth Mental Health Traits and Diagnoses within a Community-based Sample.” Canadian Journal of Psychiatry. .

Abstract

Objective

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Exposure to outdoor concentrations of fine particulate matter is considered a leading global health concern, largely based on estimates of excess deaths using information integrating exposure and risk from several particle sources (outdoor and indoor air pollution and passive/active smoking). Such integration requires strong assumptions about equal toxicity per total inhaled dose. We relax these assumptions to build risk models examining exposure and risk information restricted to cohort studies of outdoor air pollution, now covering much of the global concentration range. Our estimates are severalfold larger than previous calculations, suggesting that outdoor particulate air pollution is an even more important population health risk factor than previously thought.

Burnett RT, Chen H, Szyszkowicz M, … Peters PA, … et al. (2018) “Global Mortality and Long-Term Ambient Exposure to Fine Particulate Matter: A New Relative Risk Estimator.” Proceedings of the National Academy of Sciences USA. 115(38): 9592-9597.

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The post Surveillance of cancer risks for firefighters, police, and armed forces among men in a Canadian census cohort appeared first on Determinants.

This is another article in a large series of papers done using the 1991 Canadian Census Health and Environment Cohort (CanCHEC), making use of the linkage to the Canadian Cancer Database (1969-2010). This series, some of which are profiled on our lab website, examines cancer risks by occupation and industry. This research is led by from the and the .

Abstract

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. ()

Citation

Sritharan J, MacLeod J, Harris S, Cole DC, Harris A, Tjepkema M, Peters PA, & PA Demers. (2018). “Prostate cancer surveillance by occupation and industry: the Canadian Census Health and Environment Cohort (CanCHEC).” Cancer Medicine. 7(4): 1468-1478.

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The post Sedentary work and the risks of colon and rectal cancer by anatomical sub-site in the Canadian census health and environment cohort (CanCHEC) appeared first on Determinants.

A New Method to Jointly Estimate the Mortality Risk of Long-Term Exposure to Fine Particulate Matter and its Components

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Most studies on the association between exposure to fine particulate matter (PM_2.5) and mortality have considered only total concentration of PM_2.5 or individual components of PM_2.5, and not the combined effects of concentration and particulate composition. We sought to develop a method to estimate the risk of death from long-term exposure to PM_2.5 and the distribution of its components, namely: sulphate, nitrate, ammonium, organic mass, black carbon, and mineral dust. We decomposed PM_2.5 exposure into the sum of total concentration and the proportion of each component. We estimated the risk of death due to exposure using a cohort of ~2.4 million Canadians who were followed for vital status over 16 years. Modelling the concentration of PM_2.5 with the distribution of the proportions of components together was a superior predictor for mortality than either total PM_2.5 concentration alone, or all component concentrations modelled together. Our new approach has the advantage of characterizing the toxicity of the atmosphere in its entirety. This is required to fully understand the health benefits associated with strategies to improve air quality that may result in complex changes not only in PM_2.5 concentration, but also in the distribution of particle components.

Dan L. Crouse, Sajeev Philip, Aaron van Donkelaar, Randall V. Martin, Barry Jessiman, Paul A. Peters, Scott Weichenthal, Jeffrey R. Brook, Bryan Hubbell & Richard T. Burnett

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Ambient PM_2.5, O₃, and NO₂ Exposures and Associations with Mortality over 16 Years of Follow-Up in the Canadian Census Health and Environment Cohort (CanCHEC)

Background: Few studies examining the associations between long-term exposure to ambient air pollution and mortality have considered multiple pollutants when assessing changes in exposure due to residential mobility during follow-up.

Objective: We investigated associations between cause-specific mortality and ambient concentrations of fine particulate matter (≤ 2.5 μm; PM_2.5), ozone (O₃), and nitrogen dioxide (NO₂) in a national cohort of about 2.5 million Canadians.

Methods: We assigned estimates of annual concentrations of these pollutants to the residential postal codes of subjects for each year during 16 years of follow-up. Historical tax data allowed us to track subjects’ residential postal code annually. We estimated hazard ratios (HRs) for each pollutant separately and adjusted for the other pollutants. We also estimated the product of the three HRs as a measure of the cumulative association with mortality for several causes of death for an increment of the mean minus the 5th percentile of each pollutant: 5.0 μg/m³ for PM_2.5, 9.5 ppb for O₃, and 8.1 ppb for NO₂.

Results: PM_2.5, O₃, and NO₂ were associated with nonaccidental and cause-specific mortality in single-pollutant models. Exposure to PM_2.5 alone was not sufficient to fully characterize the toxicity of the atmospheric mix or to fully explain the risk of mortality associated with exposure to ambient pollution. Assuming additive associations, the estimated HR for nonaccidental mortality corresponding to a change in exposure from the mean to the 5th percentile for all three pollutants together was 1.075 (95% CI: 1.067, 1.084). Accounting for residential mobility had only a limited impact on the association between mortality and PM_2.5 and O₃, but increased associations with NO₂.

Conclusions: In this large, national-level cohort, we found positive associations between several common causes of death and exposure to PM_2.5, O₃, and NO₂.

Dan L. Crouse,^1,2 Paul A. Peters,² Perry Hystad,³ Jeffrey R. Brook,^4,5 Aaron van Donkelaar,⁶ Randall V. Martin,⁶ Paul J. Villeneuve,⁷ Michael Jerrett,⁸ Mark S. Goldberg,^9,10 C. Arden Pope III,¹¹ Michael Brauer,¹² Robert D. Brook,¹³ Alain Robichaud,¹⁴ Richard Menard,¹⁴ and Richard T. Burnett¹

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Other, more ephemeral elements of the urban landscape are beginning to gain more attention. In this article, overviews the work of an urban “smellscape” researcher, Kate McLean. It may seem self evident the cities such as Amsterdam (or Vancouver), we can also imagine the smells of other cities and places. Some of these bring pleasant thoughts (the smell of the sea in Victoria) or unpleasant ones (the pulp mill in Kamloops), but they form part of our daily experiences and are imprinted in our memories.

In our larger cities these smellscapes are complex and intertwine with the mosaic of cultures that fill our streets and sidewalks. The smokey smell of a coffee roaster, the sweet smell of a Greek bakery, the multi-layered smell of an Indian restaurant, the incense of Chinatown. I can think of many of these from my childhood – Granville Island and Banyan Books (Vancouver), Fan-Tan Alley or the Harbour (Victoria), Wells Grey Park or Long Beach. Other cities I’ve visited have their own smellscapes: the food markets in Bangkok, the green streets of Adelaide, musty catacombs of Lima, bookstores of London.

The above are all positive memories, but smellscapes can also be a hazard and warn us of dangers to our well-being. The above-mentioned smell of the pulp-mill in Kamloops is obvious, as is the smell of vehicle exhaust and diesel smoke. Other cities may have an acrid smell of various oxides and VOCs percolating in the air and making their way into our lungs. Globally, ambient air pollution from vehicles and industry is still  a major problem. As the metropolitan areas in developed nations become cleaner this can be ignored by the Western media. However, massive pollution is a daily fact of life for many, whether in Delhi, Beijing, Nairobi, or Lima.

Tracing smellscapes is a unique way to weave the underlying cultural fabric of the city. It is also an indicator for pollution and those smells that are potentially harmful to our health.

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In a study released in on Wednesday, September 30th, a team of researchers has further refined the number of trees via estimates of tree density. The new estimates indicate that there are approximately 3.04 trillion trees, blowing away the previously estimate of 400 billion. That means, the researchers say, that there are 422 trees for every person on Earth. However, these estimates vary widely by country and the some of the lease dense countries have the the highest density of trees.

In the table below, taken from their supplementary appendix, the top 20 countries by the number of total trees is listed. As can be seen, there are a few countries with a large land area and a correspondingly large number of trees. At the top of these are Russia, Canada, Brazil, United States and the DRC. What is interesting to me is the disproportionate effort spent on protecting trees in only some of these countries (Brazil & Congo), and only to a lesser extent in the others. A lot of this probably has to do with post-colonial mentalities, where we focus on “doing good” elsewhere rather than in our own backyard. However, a lot is probably also the influence of industry and poor government policy.

Given the strong relationship between the environment and human health, this should not only be an economic, biodiversity, use, or environmentalist agenda, but also a public health one. The advantage of a public health agenda is that it includes all of the other mentioned priorities. Public health from an ecosocial lens can include the right to employment (including in the resource sector) as well as healthy environment. Ecological determinants of health include access to nature and green space, it includes clean air and climate change, and it includes clean water and sanitation. As such, the protection of the Boreal forests is as much part of the discussion for city dwellers as for the traditional inhabitants of our lands.

In advanced industrial nations like ours, the protection of the environment and forests in particular should be a national priority. The effects of adequate protection (and growth!) of our forests could be massive and go far beyond the economic effects. Direct benefits include reduction in ozone depletion, mediation of global particulate matter, protection of biodiversity, and cleaner water sources.

From the above table, the developed nations on the list should take stock as to how they are protecting and growing their own forests. Is Canada doing enough? Is there a national strategy for forest protection and growth? Is there a national biodiversity strategy? Is the public health field sufficiently involved in the discussion? I don’t think the answer is yes to any of these questions, but it should be.

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