Archive pour le mois : juillet, 2018

Associations between Living Near Water and Risk of Mortality among Urban Canadians.

Crouse DL, Balram A, Hystad P, Pinault L, van den Bosch M, Chen H, Rainham D, Thomson EM, Close CH, van Donkelaar A, Martin RV, Ménard R, Robichaud A, Villeneuve PJ.

Environ Health Perspect. 2018 Jul 24;126(7):077008. eCollection 2018 Jul. https://doi.org/10.1289/EHP3397.

Abstract

BACKGROUND: Increasing evidence suggests that residential exposures to natural environments, such as green spaces, are associated with many health benefits. Only a single study has examined the potential link between living near water and mortality.

OBJECTIVE: We sought to examine whether residential proximity to large, natural water features (e.g., lakes, rivers, coasts, « blue space ») was associated with cause-specific mortality.

METHODS: Our study is based on a population-based cohort of nonimmigrant adults living in the 30 largest Canadian cities [i.e., the 2001 Canadian Census Health and Environment Cohort) (CanCHEC)]. Subjects were drawn from the mandatory 2001 Statistics Canada long-form census, who were linked to the Canadian mortality database and to annual income-tax filings, through 2011. We estimated associations between living within of blue space and deaths from several common causes of death. We adjusted models for many personal and contextual covariates, as well as for exposures to residential greenness and ambient air pollution.

RESULTS: Our cohort included approximately 1.3 million subjects at baseline, 106,180 of whom died from nonaccidental causes during follow-up. We found significant, reduced risks of mortality in the range of 12-17% associated with living within of water in comparison with living farther away, among all causes of death examined, except with external/accidental causes. Protective effects were found to be higher among women and all older adults than among other subjects, and protective effects were found to be highest against deaths from stroke and respiratory-related causes.

CONCLUSIONS: Our findings suggest that living near blue spaces in urban areas has important benefits to health, but further work is needed to better understand the drivers of this association.

Evaluation of daily time spent in transportation and traffic-influenced microenvironments by urban Canadians. 

Matz CJ, Stieb DM, Egyed M, Brion O, Johnson M. 

Air Qual Atmos Health. 2018;11(2):209-220. DOI:10.1007/s11869-017-0532-6

Abstract

Exposure to traffic and traffic-related air pollution is associated with a wide array of health effects. Time spent in a vehicle, in active transportation, along roadsides, and in close proximity to traffic can substantially contribute to daily exposure to air pollutants. For this study, we evaluated daily time spent in transportation and traffic-influenced microenvironments by urban Canadians using the Canadian Human Activity Pattern Survey (CHAPS) 2 results. Approximately 4-7% of daily time was spent in on- or near-road locations, mainly associated with being in a vehicle and smaller contributions from active transportation. Indoor microenvironments can be impacted by traffic emissions, especially when located near major roadways. Over 60% of the target population reported living within one block of a roadway with moderate to heavy traffic, which was variable with income level and city, and confirmed based on elevated NO₂ exposure estimated using land use regression. Furthermore, over 55% of the target population ≤ 18 years reported attending a school or daycare in close proximity to moderate to heavy traffic, and little variation was observed based on income or city. The results underline the importance of traffic emissions as a major source of exposure in Canadian urban centers, given the time spent in traffic-influenced microenvironments.

Long-term exposure to air pollution and the incidence of multiple sclerosis: A population-based cohort study.

Bai L, Burnett RT, Kwong JC, Hystad P, van Donkelaar A, Brook JR, Tu K, Copes R, Goldberg MS, Martin RV, Murray BJ, Kopp A, Chen H.

Environ Res. 2018 Jun 22;166:437-443.  [Epub ahead of print] DOI:10.1016/j.envres.2018.06.003

Abstract

BACKGROUND:

Evidence of the adverse neurological effects of exposure to ambient air pollution is emerging, but little is known about its effect on the development of multiple sclerosis (MS), the most common autoimmune disease of the central nervous system.

OBJECTIVES:

To investigate the associations between MS incidence and long-term exposures to fine particles (PM_2.5), nitrogen dioxide (NO₂), and ozone (O₃) METHODS: We conducted a population-based cohort study to investigate the associations between long-term exposures to PM_2.5, NO₂, and O₃ and the incidence of MS. Our study population included all Canadian-born residents aged 20-40 years who lived in the province of Ontario, Canada from 2001 to 2013. Incident MS was ascertained from a validated registry. We assigned estimates of annual concentrations of these pollutants to the residential postal codes of subjects for each year during the 13 years of follow-up. We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for each pollutant separately using random-effects Cox proportional hazards models. We conducted various sensitivity analyses, such as lagging exposure up to 5 years and adjusting for access to neurological care, annual average temperature, and population density.

RESULTS:

Between 2001 and 2013, we identified 6203 incident cases of MS. The adjusted HR of incident MS was 0.96 (95% CI: 0.86-1.07) for PM_2.5, 0.91(95% CI: 0.81-1.02) for NO₂, and 1.09 (95% CI: 0.98-1.23) for O₃. These results were robust to various sensitivity analyses conducted.

CONCLUSIONS:

In this large population-based cohort, we did not observe significant associations between MS incidence and long-term exposures to PM_2.5, NO₂, and O₃ in adults in Ontario, 2001-2013.