Outdoor air pollution and out-of-hospital cardiac arrest in Okayama, Japan.

OBJECTIVES

We evaluated the association between short-term exposure to outdoor air pollution and out-of-hospital cardiac arrest in Japan.

METHODS

We studied 558 residents of Okayama, Japan, who visited hospital emergency departments between January 2006 and December 2010 for out-of-hospital cardiac arrest using a time-stratified case-crossover design. We calculated city-representative average concentrations of different air pollutants and examined the association between air pollution and cardiac arrest.

RESULTS

Exposure to air pollution was associated with an elevated risk of cardiac arrest; for example, odds ratios was 1.17 (95% confidence interval, 1.02 to 1.33) per interquartile-range increase in suspended particulate matter concentrations in the previous 48 to 72 hours. We also observed different susceptibilities to suspended particulate matter and ozone exposures by age category.

CONCLUSIONS

Short-term exposure to outdoor air pollution was associated with increased risk of cardiac arrest.