Industrial air pollutant emissions and mortality from Alzheimer's disease in Canada
- DOI
- Language of the publication
- English
- Date
- 2022-08-19
- Type
- Article
- Author(s)
- Cakmak, Sabit
- Toyib, Olaniyan
- Hebbern, Chris
- Mitchell, Kimberly
- Cakmak, Jasmine D.
- Lavigne, Eric
- Tjepkema, Michael
- Zhao, Naizhuo
- Publisher
- ScienceDirect
Abstract
Background There 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. Objectives To assess associations of industrial fine particulate matter (PM2.5), nitrogen dioxide (NO2), and sulfur dioxide (SO2) exposures with mortality from Alzheimer's disease. Methods Approximately 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. Results We 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. Conclusions Exposure to industrial PM2.5 increases the risk of mortality from Alzheimer's disease.
Plain language summary
Under the AAPHI (Addressing Air Pollution Horizontal Initiative), Health Canada conducts scientific research to evaluate the health risks of environmental factors, such as outdoor air pollution at different sources. There is evidence that industrial sourced ambient air pollution can adversely affect health outcomes. Increasing evidence is available for an association between long term particulate matter (PM2.5), nitrogen dioxide (NO2) and sulfur dioxide (SO2) exposure and Alzheimer mortality, although uncertainties remain around the strength of the causal link, due to difficulties accounting for changes in exposure over time, differences in the ambient pollution mix in different areas, and the long time period required for development of Alzheimer. In this study, we looked at the relationship between long-term industrial sourced PM2.5, NO2, and SO2 exposures and their association with Alzheimer mortality in the Canadian Census Health and Environment Cohort (CANCHEC). We estimated exposure to pollution based on residential postal codes and used statistical models to compare these exposures with records of death from Alzheimer’s. We found a relationship between industrial PM2.5 emissions and mortality from Alzheimer’s disease. However, we did not observe a clear association of mortality with industrial NO2/SO2 emissions. Our findings indicate the need for further studies with more accurate estimates of industrial pollution emissions and more flexible statistical methods to determine if these associations are causal. This work will help to inform risk assessors and policy makers at Health Canada, and in other jurisdictions, about the effects of specific sources of outdoor air pollution.
Subject
- Health,
- Health and safety