Hygiene and Environmental Health Advances (Dec 2022)
Industrial air pollutant emissions and mortality from Alzheimer's disease in Canada
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.
