At Low Temps, Air Pollution May Up Risk of Sudden Cardiac Death

Particulate matter less than 2.5 µm in diameter linked to higher sudden cardiac death risk in women.
Particulate matter less than 2.5 µm in diameter linked to higher sudden cardiac death risk in women.

HealthDay News — Exposure to particulate matter less than 2.5µm in diameter (PM2.5) is associated with increased risk of sudden cardiac death (SCD) at low temperatures in women, according to a study presented at the annual meeting of the Heart Rhythm Society, held from May 9 to 12 in Boston.

Jamie E. Hart, ScD, from Brigham and Women's Hospital and Harvard Medical School in Boston, and colleagues examined the correlation between PM exposure and SCD among 112,061 women enrolled in the Nurses' Health Study. Daily exposures to PM2.5 and mean temperatures were ascertained at each participant's address. 

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The researchers identified 221 SCDs between 1999 and 2011. Increasing PM2.5 exposures on the same day correlated with a trend toward increase in SCD risk (odds ratio, 1.22; 95% confidence interval [CI], 0.97 to 1.53; P=.09) for each interquartile range increase in exposure (7.72 µg/m³). Ambient temperature significantly modified this correlation. In the lowest quartiles of temperatures, PM2.5 was significantly associated with SCD (quartile 1 [<39.03 degrees Fahrenheit]: odds ratio, 1.95; 95% CI, 1.83 to 2.09; P=.01; quartile 2 [39.03 to 54.65 degrees Fahrenheit]: odds ratio, 2.56; 95% CI, 2.35 to 2.80; P=.007). There were no correlations between PM2.5 and SCD in the higher quartiles.

"Our study demonstrates that even a small amount of air pollution on colder days could put people at risk," Hart said in a statement.

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