Long Term Exposure to Fine Particulate Matter and Mortality among Women Enrolled in the Canadian National Breast Screening Study

Abstract

Long Term Exposure to Fine Particulate Matter and Mortality among Women Enrolled in the Canadian National Breast Screening StudyAbstract Number:1888 Paul Villeneuve*, Teresa To, Scott Weichenthal, Dan Crouse, Aaron van Donkelaar, Randall Martin, Claus Wall, Rick Burnett, and Anthony Miller Paul Villeneuve* Carleton University, Canada, E-mail Address: [email protected] Search for more papers by this author , Teresa To Hospital for Sick Children, Canada, E-mail Address: [email protected] Search for more papers by this author , Scott Weichenthal Health Canada, Canada, E-mail Address: [email protected] Search for more papers by this author , Dan Crouse Health Canada, Canada, E-mail Address: [email protected] Search for more papers by this author , Aaron van Donkelaar Dalhousie University, Canada, E-mail Address: [email protected] Search for more papers by this author , Randall Martin Dalhousie University, Canada, E-mail Address: [email protected] Search for more papers by this author , Claus Wall University of Toronto, Canada, E-mail Address: [email protected] Search for more papers by this author , Rick Burnett Health Canada, Canada, E-mail Address: [email protected] Search for more papers by this author , and Anthony Miller University of Toronto, Canada, E-mail Address: [email protected] Search for more papers by this author AbstractBackground: Long-term exposure to fine particulate matter (PM2.5) has been associated with increased mortality rates for cardiovascular disease and lung cancer but there remain uncertainties about these relationships at lower concentrations. While Canadian studies have found positive associations at low levels for several health outcomes, they have often been limited by a lack of individual-level data for other mortality risk factors.Methods: We investigated associations between long-term exposure to PM2.5 and mortality in a prospective cohort of 89,292 women who were enrolled in the Canadian National Breast Screening Study. They were between the ages of 40 and 60 when they entered the study in 1980-4. Record linkage to national mortality data was performed to identify deaths through 2005. Individual-level estimates of long-term exposure to fine particulate matter were derived from satellite observations and participants’ residential addresses. The Cox proportional hazards model was used to characterize associations between PM2.5 and several mortality outcomes. The hazard ratios derived from these models were adjusted for several individual-level variables measured at baseline including smoking, and obesity as well as neighborhood socio-demographic measures obtained from census data.Results: The cohort was composed predominantly of Canadian born (82%) and married (80%) women. The average concentration of PM2.5 observed in the cohort was 9.50 µg/m3 (standard deviation=3.44). In fully adjusted models, a 10 µg/m3 increase in PM2.5 exposure was associated with a higher risk of ischemic heart disease mortality (HR=1.32, 95% CI=1.14-1.53) and non-accidental mortality (HR, 1.12; 95% CI, 1.04-1.19).Conclusions: Low-levels of ambient PM2.5 were positively associated with cardiovascular and non-accidental mortality after taking into account individual-level measures of obesity and smoking.