Air Pollution and Cardiovascular Disease in the California Teachers Study Cohort

There are few studies examining associations between long-term exposure to air pollution and adverse health outcomes. In an ongoing cohort study of over 100,000 female participants in the California Teachers Study (CTS), we developed estimates of long-term air pollution exposure at the subjects' residences and examined associations between these exposure estimates and the following health outcomes: total mortality, cardiopulmonary mortality, and incidence ofboth fatal and non-fatal heart attacks and stroke. In addition, we examined the potential impacts of several traffic metrics on these outcomes. In order to derive the pollutant exposure metrics, the CTS participants' addresses were linked with monthly estimates oflong-term exposure to multiple air pollutants, including PM2.5 (particulate matter less than 2.5 microns in diameter), PMJ0, and several gases (including ozone, carbon monoxide (CO), nitrogen dioxide (N02), and others). The addresses were linked as well with several cross-sectional measures of traffic-related exposures from the year 2000 or later. We analyzed these relationships while adjusting for many individual-level and neighborhood variables, and undertook a variety of sensitivity analyses. We found strong and consistent associations of PM2.5 not only with total and cardiopulmonary mortality, but also with the incidence of heart attacks and stroke. We also identified somewhat less consistent relationships between one or more of these adverse outcomes and PMJ0, CO, N02 and ozone. Most of the traffic metrics were not associated with these outcomes. This study provides additional evidence that long-tenn exposure to air pollution is associated with mortality, and demonstrates as well that exposure to several combustion-related pollutants is associated with the incidence of new cases of heart attacks and stroke.