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Forget extreme temperatures: Nothing kills as many people as moderate cold

Some are scoffing at the idea that rising heating costs will kill people. But check out the number-one temperature-killer in 74 million deaths across 13 countries. It’s not the extremes that we need to worry about, the deadly phrase is “mildly suboptimal temperatures”. Look at the blue finger of death in the graph below, starkly showing how irrelevant “extreme heat”, or any other ambient temperature zone, is.

Do you need an excuse to turn the heater on in winter? Low ambient room temperatures will thicken your blood.

Moderate cold accounted for as many as 6.6% of all deaths. Extreme temperatures (either cold or hot) were responsible for only 0·86%.

Join the dots — will we save more lives by:

a) making homes cold now in the hope that lower “carbon” emissions will,

b) mean less deaths from heat in 90 years time despite people probably having better access to heaters and air conditioners?

Would you sacrifice ten years of your life…

Death rates, mortality, international, room temperature, Lancet, graph.

Note the big killer “moderate cold”  |  Click to enlarge

Cold is more likely to kill you in Sydney than in Sweden

Check out the curves below. As a percentage of the population, there are more deaths in Sydney than in Bejing at 5C.

Australian houses are not designed to be warm. Sweden’s are.

Lancet, Graph, Death, Mortality. excess, country, ambient temperature, UK, USA, Australia, Korea, Canada, Sweden, Taiwan, Italy, BrazilJapan.

Figure 1 shows overall cumulative exposure-response curves (best linear unbiased predictions) for 13 cities selected to represent each country, with the corresponding minimum mortality temperature and the cutoff s to defi ne extreme temperatures. |. Click to enlarge

Blame house design, we Australians don’t take the cold seriously (read more about the flaws at this link).

Professor Adrian Barnett, a researcher based at the Queensland University of Technology, has studied death rates associated with abnormal weather conditions plus occupant access to heating and cooling, and has established a link to the quality of housing in Australia and a corresponding increase in death rates during cold spells.

Professor Barnett’s studies have concluded that Australia’s death rate due to cold weather, which at 6.5% is almost double that of Sweden’s at 3.9%, is almost entirely due to the poor quality to which we build our homes.

Swedish homes are designed and built to stay comfortable during all weather conditions, whereas comfort in Australian homes is often an afterthought, usually covered by an oversized air conditioner which continually battles poorly insulated walls, leaky doors and windows.  Australian homes are referred to as “glorified tents” due to this phenomenon, which particularly affects less affluent homeowners and of course, renters.

The internal temperatures of Federation or Queenslander style homes in winter often drop well below 17°C, while Swedish homes usually remain at a stable 22-23°C whatever the weather.  According to Barnett, “Many Australian homes are just glorified tents and we expose ourselves to far colder temperatures than the Scandinavians do.”

In the Energy + Illawarra program the University of Wollongong’s Sustainable Buildings Research Centre team recently identified surprisingly cold living conditions in 158 households across the Illawarra, Shoalhaven & Wingecarribee regions of NSW.  Researchers found that approximately half of all households studied were experiencing extended periods (>25% of the time) when the living room temperatures were well below 16°C.  In fact some houses did not exceed 14°C throughout a number of days, some occupants reported being too anxious to turn heating on due to the cost of energy and ‘bill anxiety’.

Save carbon emissions and raise your blood pressure

In the cold, the naked ape suffers from thickened blood, local inflammation, weakened immunity, bronchoconstriction:

 The biological processes that underlie cold-related mortality mainly have cardio vascular and respiratory effects. Exposure to cold has been associated with cardiovascular stress by aff ecting factors such as blood pressure and plasma fibrinogen, vasoconstriction and blood viscosity, and inflammatory responses. Similarly, cold induces bronchoconstriction and suppresses mucociliary defences and other immunological reactions, resulting in local inflammation and increased risk of respiratory infections. These physiological responses can persist for longer than those attributed to heat, and seem to produce mortality risks that follow a smooth, close-to-linear response, with most of the attributable risk occurring in moderately cold days.

 I wrote about this enormous study, on 74 million deaths across Australia, Brazil, Canada, China, Italy, Japan, South Korea, Spain, Sweden, Taiwan, UK & USA: Cold weather kills 20 times more than heat does. But the paper is now fully available with more detail, and hardly any politician seems to have got the message the first time around. Hence the revisit.

Please someone send this to Craig Kelly and the SMH.

The benefits we can derive,
From warming, helps keep us alive,
While our true foe is cold,
Killing both young and old,
Who with warming would otherwise thrive.

  Ruairi

REFERENCE

Antonio Gasparrini et al.  (2015) Mortality risk attributable to high and low ambient temperature: a multicountry observational study. The Lancet, May 2015 DOI: 10.1016/S0140-6736(14)62114-0Full PDF.

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