Ozone Levels PM2.5 Linked to Out-of-Hospital Cardiac Arrest
Exposure to ozone at short time scales and on day of event linked to increased risk
MONDAY, Feb. 18 (HealthDay News) -- There is an increased risk of out-of-hospital cardiac arrest (OHCA) with higher levels of exposure to fine particulate matter (PM2.5) and ozone, according to a study published online Feb. 13 in Circulation.
To examine the correlation between OHCA and air pollution concentrations in the hours or days before onset, Katherine B. Ensor, Ph.D., from Rice University in Houston, and colleagues used data from 11,677 emergency medical service-logged OHCA events from 2004 to 2011 in Houston.
The researchers observed an increased risk of OHCA with an average increase of 6 µg/m³ in PM2.5 two days before onset (1.046; 95 percent confidence interval [CI], 1.012 to 1.082). There was an increased risk of OHCA with a 20 parts per billion (ppb) ozone increase for the eight-hour average daily maximum on the day of the event (1.039; 95 percent CI, 1.005 to 1.073). For each 20 ppb increase in ozone in the previous one to three hours there was an increased risk of OHCA (1.044; 95 percent CI, 1.004 to 1.085). Men, African-Americans, and those aged over 65 years had higher relative risk estimates.
"While this study identifies an association between PM2.5 and ozone air pollution and OHCA, future research to better define the exposure time period associated with triggering an OHCA is needed," the authors write.