Exposure to Air Pollution and Particle Radioactivity With the Risk of Ventricular Arrhythmias

Abstract

Background: Individuals are exposed to air pollution and ionizing radiation from natural sources through inhalation of particles. This study investigates the association between cardiac arrhythmias and short-term exposures to fine particulate matter (particulate matter ≤2.5 µm aerodynamic diameter; PM_2.5) and particle radioactivity.

Methods: Ventricular arrhythmic events were identified among 176 patients with dual-chamber implanted cardioverter-defibrillators in Boston, Massachusetts between September 2006 and June 2010. Patients were assigned exposures based on residential addresses. Daily PM_2.5 levels were estimated at 1-km×1-km grid cells from a previously validated prediction model. Particle gross β activity was used as a surrogate for particle radioactivity and was measured from several monitoring sites by the US Environmental Protection Agency's monitoring network. The association of the onset of ventricular arrhythmias (VA) with 0- to 21-day moving averages of PM_2.5 and particle radioactivity (2 single-pollutant models and a 2-pollutant model) before the event was examined using time-stratified case-crossover analyses, adjusted for dew point and air temperatures.

Results: A total of 1,050 VA were recorded among 91 patients, including 123 sustained VA among 25 of these patients. In the single-pollutant model of PM_2.5, each interquartile range increase in daily PM_2.5 levels for a 21-day moving average was associated with 39% higher odds of a VA event (95% CI, 12%-72%). In the single-pollutant model of particle radioactivity, each interquartile range increase in particle radioactivity for a 2-day moving average was associated with 13% higher odds of a VA event (95% CI, 1%-26%). In the 2-pollutant model, for the same averaging window of 21 days, each interquartile range increase in daily PM_2.5 was associated with an 48% higher odds of a VA event (95% CI, 15%-90%), and each interquartile range increase of particle radioactivity with a 10% lower odds of a VA event (95% CI, -29% to 14%). We found that with higher levels of particle radioactivity, the effect of PM_2.5 on VAs is reduced.

Conclusions: In this high-risk population, intermediate (21-day) PM_2.5 exposure was associated with higher odds of a VA event onset among patients with known cardiac disease and indication for implanted cardioverter-defibrillator implantation independently of particle radioactivity.

Keywords: fine particulate matter; implanted cardioverter-defibrillators; particle radioactivity; ventricular arrhythmia.

Figure 1:

Log odds ratios of ICD Detected Ventricular Arrhythmias Associated with Each Interquartile Range Increase in Mean (A) Fine Particulate Matter (PM_2.5) or (B) Particle radioactivity 0–21 days prior to the Arrhythmic Event, Adjusted for Temperature and Dew Point in the ICD cohort from September 1, 2006 to June 30, 2010. * p<0.05; ** p<0.01