Tuesday, 7 January 2014
Out in the cold - the understudied public health effects of frigid temperature
For those who have any interest in the relationship between health and weather, this site has some interesting postings. Weather that kills; Communicating the risks of weather; air pollution and AQHI
As a polar vortex captures much of North America, and temperatures in Saskatchewan are at in inhumane -50 C wind chills, there is lots of talk about the safety concerns since we all know the discomfort associated with getting too cold.
Little is said of the deaths associated with cold. For some reason, we have been able to parse out the impact of heat, but have little on the impact of cold. Multiple studies have demonstrated that the risks associated with subzero temperatures continue to rise as temperature drops, in fact the risk begins to increase as temperature dips below about 20C, so once we are into subzero temperatures, the relative risk is about 10% higher, and by -30 that risks is over 20% and likely closer to 30% - however the data are scarce since major cities don’t experience such extreme temperatures for long enough periods to parse out the impact (for examples see AJE eastern US cities)
Frustratingly, even in studies looking at ambient temperature, the focus is on the increased temperature such as science direct Asian capitals while the graphic relationship shows the steeper curve in mortality as temperature drops
So why is cold, being left out in the cold? The relationship between the increase in deaths seems to be more complex, as issues like wintertime crowding, circulation of influenza and other viruses complicate the analysis of the long term baseline information. This should be adjustable for, and in doing so some estimates of the real risks of cold weather undertaken.
As this site has noted, it may be estimated that colder climates contribute up to 5000 deaths annually in Canada.
So as we bundle ourselves inside, perhaps someone with time series regression knowledge might produce a paper on what we in Canada know only too well, that the cold can be uncomfortable and tragically it sometimes kills.
For the sociologists, some understanding of who is affected by hypothermia and who dies during cold spells would help fill an icy void in our understanding of the Canadian chill.
Why is this an understudies area? Look at the news, the concern is about infrastructure, about being stranded in heated airports, about the inconvenience in having events and schools closed. It affects us all in our daily activities, and perhaps in doing so we are sliding over those that suffer through such disastrous temperatures.