February 25 | 2019

Spatiotemporal Variations in Ambient Ultrafine Particles and the Incidence of Childhood Asthma.

Lavigne E, Donelle J, Hatzopoulou M, Van Ryswyk K, van Donkelaar A, Martin R, Chen H, Stieb DM, Gasparrini A, Crighton E, Yasseen Iii AS, Burnett RT, Walker M, Weichenthal S.

Am J Respir Crit Care Med. 2019 Feb 20.. [Epub ahead of print]  DOI: 10.1164/rccm.201810-1976OC




Little is known regarding the impact of ambient ultrafine particles (<0.1 μm) (UFPs) on childhood asthma development.


To examine the association between prenatal and early postnatal life exposure to UFPs and development of childhood asthma.


A total of 160,641 singleton live births occurring in the City of Toronto, Canada between April 1st 2006 and March 31st 2012 were identified from a birth registry. Associations between exposure to ambient air pollutants and childhood asthma incidence (up to age 6) were estimated using random-effects Cox proportional hazards models, adjusting for personal- and neighborhood-level covariates. We investigated both single- and multi-pollutant models accounting for co-exposures to PM2.5 and NO2.


We identified 27,062 children with incident asthma diagnosis during the follow-up. In adjusted models, second trimester exposure to UFPs (Hazard Ratio (HR) per interquartile (IQR) increase = 1.09, 95% CI: 1.06 – 1.12) was associated with asthma incidence. In models additionally adjusted for PM2.5 and NO2, UFPs exposure during the second trimester of pregnancy remained positively associated with childhood asthma incidence (HR per IQR increase = 1.05, 95% CI: 1.01 – 1.09).


This is the first study to evaluate the association between perinatal exposure to UFPs and the incidence of childhood asthma. Exposure to UFPs during a critical period of lung development was linked to the onset of asthma in children, independent of PM2.5 and NO2.

February 19 | 2019

Health Benefits of Physical Activity Related to an Urban Riverside Regeneration.

Vert C, Nieuwenhuijsen M, Gascon M, Grellier J, Fleming LE, White MP, Rojas-Rueda D.

Int J Environ Res Public Health. 2019 Feb 5;16(3). pii: E462. Doi: 10.3390/ijerph16030462



The promotion of physical activity through better urban design is one pathway by which health and well-being improvements can be achieved. This study aimed to quantify health and health-related economic impacts associated with physical activity in an urban riverside park regeneration project in Barcelona, Spain. We used data from Barcelona local authorities and meta-analysis assessing physical activity and health outcomes to develop and apply the « Blue Active Tool ». We estimated park user health impacts in terms of all-cause mortality, morbidity (ischemic heart disease; ischemic stroke; type 2 diabetes; cancers of the colon and breast; and dementia), disability-adjusted life years (DALYs) and health-related economic impacts. We estimated that 5753 adult users visited the riverside park daily and performed different types of physical activity (walking for leisure or to/from work, cycling, and running). Related to the physical activity conducted on the riverside park, we estimated an annual reduction of 7.3 deaths (95% CI: 5.4; 10.2), and 6.2 cases of diseases (95% CI: 2.0; 11.6). This corresponds to 11.9 DALYs (95% CI: 3.4; 20.5) and an annual health-economic impact of 23.4 million euros (95% CI: 17.2 million; 32.8 million). The urban regeneration intervention of this riverside park provides health and health-related economic benefits to the population using the infrastructure.

February 11 | 2019

Exposure to natural space, sense of community belonging, and adverse mental health outcomes across an urban region.

Rugel EJ, Carpiano RM, Henderson SB, Brauer M.

Environ Res. 2019 Jan 25;171:365-377. DOI: 10.1016/j.envres.2019.01.034


In a rapidly urbanizing world, identifying evidence-based strategies to support healthy design is essential. Although urban living offers increased access to critical resources and can help to mitigate climate change, densely populated neighborhood environments are often higher in many of the physical and psychological stressors that are detrimental to health, and lower in the social capital that is beneficial to health. One component of urban form that can reduce these stressors and improve social capital is nature: greenspace, such as parks and street trees, and bluespace, such as rivers and oceans. In this project, we applied measures from a Natural Space Index previously developed for the Vancouver, Canada census metropolitan area to explore the relationship between distinct measures of natural space and prevalence of (1) major depressive disorder, (2) negative mental health, and (3) psychological distress. In addition, we examined direct associations between natural space exposure and neighborhood social capital, as measured via self-reported sense of community belonging (SoC), as well as the potential mental health benefits of natural space mediated via SoC. Using data from the population-based, cross-sectional 2012 Canadian Community Health Survey-Mental Health (weighted n = 1,930,048), we found no direct associations between any measure of natural space and mental health in models adjusted for 11 demographic, socioeconomic, household arrangement, health, and urban design variables. However, publicly accessible neighborhood nature was associated with increased odds of higher SoC. A 1% increase in the percentage of natural space (combined greenspace and bluespace) within 500 m had an odds ratio [95% confidence interval] of 1.05 [1.00, 1.10] for very strong vs. very weak SoC and 1.04 [1.01, 1.08] for somewhat strong vs. very weak SoC. In addition, higher levels of SoC were associated with improvements in all three mental health outcomes. Mediation tests indicated significant indirect effects of both publicly accessible neighborhood nature variables on reductions in psychological distress and reduced odds of negative mental health via increased sense of SoC. This suggests that natural space has the potential to address the pressing issue of social isolation and, in turn, poor mental health faced by residents of dense urban environments.

Interactive Mapping of Environmental Health Assessments | MARCH 19 | 2019

9am-10am pacific | 12 noon – 1pm eastern


Non communicable diseases including cardiovascular disease, diabetes, and cancer are the leading causes of morbidity and mortality among populations in high income countries. The rapid increase of overweight and obesity among Canadians and its associated consequences, including hypertension and diabetes is a major public health problem, and threaten to halt the declines in cardiovascular disease deaths Canada has experienced in the past 30 years.

Knowledge gaps exist regarding the impact of the built environment in relation to individual risk factor development, and the variation of these built environments across Canada by region and rurality. In order to address these gaps in our knowledge, we convened the Canadian Alliance of Healthy Hearts and Minds – a prospective cohort of men and women recruited from existing cohorts in Canada and through recruitment of a new First Nations cohort study.

As part of the knowledge translation plan of the Canadian Alliance for Healthy Hearts and Minds project, we developed and released an on-line, interactive map of 2,074 communities across Canada that conveys the information from our community contextual health audits. In this presentation, I will describe the development of the map, and describe how to access and use the tools embedded in the map.

Russell de Souza is an Assistant Professor in the Department of Health Research Methods, Evidence, and Impact at McMaster University.  He is a registered dietitian, and his research focuses on dietary patterns, health, and how the food environment shapes food choice and risk of cardiovascular disease.







Ambient Air Pollution and the Risk of Childhood-onset Inflammatory Bowel Disease | FEBRUARY 12 | 2019

9am-10am pacific | 12 noon – 1pm eastern



 The incidence of inflammatory bowel disease (IBD) has risen drastically in industrialized nations, such as Canada, over the last half of the 20th century. Although the incidence rate in adults with IBD has plateaued in Canada, the incidence of IBD among Canadian children is continuing to rise. Environmental risk factors, such as air pollution may be involved in IBD development, but epidemiological studies are inconclusive.

This presentation will summarize the results from a study investigating the effects of ambient air pollution on the risk of developing pediatric-onset IBD using Ontario administrative health data. In-utero and childhood residential exposures to nitrogen dioxide (NO2), fine particulate matter (PM2.5) and ozone (O3) were evaluated in terms of their potential associations with IBD diagnosed before the age of 18. Other environmental factors, such as residential exposure to greenness as well as several maternal and individual-level factors were also considered as potential confounders and effect modifiers of these associations.

Michael Elten is currently completing a Master’s degree in Epidemiology in the School of Epidemiology and Public Health at the University of Ottawa. His research focuses on evaluating the effects of air pollution on health, with an emphasis on maternal and early-life exposures.







February 4 | 2019

Neighbourhood walkability and the incidence of diabetes: an inverse probability of treatment weighting analysis.

Booth GL, Creatore M, Luo J, Fazli GS, Johns A, Rosella LC, Glazier RH, Moineddin R, Gozdyra P, Austin PC.

J Epidemiol Community Health. 2019 Jan 29.. [Epub ahead of print]  DOI:10.1136/jech-2018-210510



People living in highly walkable neighbourhoods tend to be more physically active and less likely to be obese. Whether walkable urban design reduces the future risk of diabetes is less clear.


We used inverse probability of treatment weighting to compare 10-year diabetes incidence between residents living in high-walkability and low-walkability neighbourhoods within five urban regions in Ontario, Canada. Adults (aged 30-85 years) who were diabetes-free on 1 April 2002 were identified from administrative health databases and followed until 31 March 2012 (n=958 567). Within each region, weights reflecting the propensity to live in each neighbourhood type were created based on sociodemographic characteristics, comorbidities and healthcare utilisation and incorporated into region-specific Cox proportional hazards models.


Low-walkability areas were more affluent and had more South Asian residents (6.4%vs3.6%, p<0.001) but fewer residents from other minority groups (16.6%vs21.7%, p<0.001). Baseline characteristics were well balanced between low-walkability and high-walkability neighbourhoods after applying individual weights (standardised differences all <0.1). In each region, high walkability was associated with lower diabetes incidence among adults aged <65 years (overall weighted incidence: 8.2vs9.2 per 1000; HR 0.85, 95% CI 0.78 to 0.93), but not among adults aged ≥65 years (weighted incidence: 20.7vs19.5 per 1000; HR 1.01, 95% CI 0.91 to 1.12). Findings were consistent regardless of income and immigration status.


Younger adults living in high-walkability neighbourhoods had a lower 10-year incidence of diabetes than similarly aged adults living in low-walkability neighbourhoods. Urban designs that support walking may have important benefits for diabetes prevention.