Abstract P002: Long Term Exposure to Outdoor Air Pollution and Cardiovascular Health

Abstract

BACKGROUND: Although the link between air pollution and cardiovascular disease has been controversial in recent decades, it remains a top global health concern. Most studies have assessed only the relationship between pollutant concentrations and morbidity or mortality in populous cities. In this study, we investigated the association of long term exposure to major air pollutants with current cardiovascular health. This outcome was a measure of health rather than disease, as measured by the Cardiovascular Health Index (CVHI) developed by the American Heart Association. METHODS: We analyzed 2011 data from 3007 counties across the US using Behavioral Risk Factor Surveillance System and Area Health Resources File. Air Quality Index (AQI) for five major pollutants from 2001-2011; Ozone, Sulfur dioxide and Carbon monoxide and Fine particulate matter (aerodynamic diameter of 10 and ≤2.5 μm) were obtained from the EPA Air Quality System database. Categories were based on the 11-year average pollutant AQI level and using Jenks optimization method; persistently good, variant and persistently bad. Associations between categories and the mean CVHI were evaluated using Poisson regression models adjusting for age, sex, race/ethnicity and socioeconomic status at the individual and population level. RESULTS: PM2.5 was most frequently measured (938 counties) and carbon monoxide least frequently (224 counties). Correlations between pollutants were moderate and significant (p<0.0001), ranging from r=0.30 between CO and Oz to r=0.52 between SD and PM2.5. Four pollutants had 11-year average AQI levels significantly associated with increased mean CVHI score of individuals. Living in a county categorized as ‘persistently good’ or ‘variant’ AQI levels for ozone is significantly associated with an estimated 3% increase in CVHI (95% CI 0.1% - 5.0%) as compared to living in a county of ‘persistently bad’ AQI levels. In addition, living in a county of only ‘persistently good’ AQI levels for PM2.5 is significantly associated with an estimated 5% increase in CVHI (95% CI 3% - 9%) as compared to living in a county of ‘persistently bad’ AQI levels. Inverse relationships existed for both PM10 and carbon monoxide. CONCLUSIONS: It is difficult to tease apart the independent effects of individual air pollutants on health as humans are exposed to a mixture of gases. However we have shown that at the individual level, there is an association between long term exposure to air pollution and its effects on current cardiovascular health. Further research is needed to determine whether these effects exist at varying levels of subject characteristics.