Abstract 15030: Exposure to Traffic Increases the Risk of Sudden Cardiac Death

Abstract

Background: Long-term exposures to air pollution, especially from traffic sources, have been associated with increased cardiovascular (CVD) morbidity and mortality; however, the mechanisms have not been fully elucidated. Since driving and air pollution have also been associated with ventricular arrhythmias in patients with implantable cardioverter defibrillators, we hypothesized that exposure to traffic might more broadly elevate sudden cardiac death (SCD) risk.

Methods: As a proxy for traffic exposure, we calculated distance to the nearest of several different US Census Feature Class road segments (in meters) for all residential addresses among 87,189 women from the Nurses' Health Study, a prospective cohort study of women aged 30-55 at study inception in 1976. SCD was defined as death within 1 hour of symptom onset and was confirmed through autopsy/medical reports. Information on a variety of risk factors for SCD was available from biennial questionnaires. Time-varying multivariable Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (95%CI) of the effect of distance to road on disease risk.

Results: There were a total of 292 cases of SCD over the 26 years of follow-up (1984-2010). As shown in Table 1, women living closer to roadways had an elevated risk of SCD. These risks were somewhat attenuated in multivariable models, but remained statistically significantly elevated among women living within 50 meters of a major road. As compared to women living 200m or more away, women within 50 meters of any major roadway had a 37% increased risk of SCD.

Conclusions: These prospective data suggest that exposure to traffic (as measured by distance to road) is associated with an increased risk of SCD in this group of middle-aged and elderly women.