Pollution Free Cities: Heart Attacks in Cold Cities

Friday, October 19, 2012

Heart Attacks in Cold Cities

English: Pneumonia and influenza mortality for 122 US cities, 4 years through week ending October 31, 2009. This time series shows the seasonality of seasonal influenza, and that during the 2007-2008 season influenza exceeded the US epidemic threshold. (Photo credit: Wikipedia)

Influenza epidemics, seasonality, and the effects of cold weather on cardiac mortality(20 page pdf, Stephanie von Klot, Antonella Zanobetti and Joel Schwartz, Environmental Health, Oct.1, 2012)

Today we review a study of a large sample of seniors in 78 cities across the USA to assess what impact cold weather has on heart attacks and how much influence influenza epidemics has on the mortality rate – in the absence, unfortunately, of corresponding air pollution data which is known to have health impacts. Results indicate that there is a link between variations in mortality rates with the influenza. While these results are interesting, a similar study in colder countries with many more sub-zero winter days, such as Russia or Canada, along with associated air pollution data would be revealing.

Key Quotes:

“extremes in ambient temperature are associated with short term increases in mortality”

“hypothesized that the principle reason for the winter time increase in cardiac deaths is respiratory, primarily influenza epidemics”

“influenza related cardiac deaths over the study period added up to 69,714 over the cities, 2.3% of all cardiac deaths observed”

“In this study on the temperature effects on cardiac mortality we did not adjust for air pollution. The reason was that there were many cities with sparse air pollution data”

“we showed in a multi-city study that the association of cardiac mortality with ambient temperature could be parsimoniously fit by including influenza data into the time series analyses”