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Coronary Disease in Australia
Enquselassie, F., Dobson, A.J., Alexander, H.M. and Steele, P.L.  1993.  Seasons, temperature and coronary disease.  International Journal of Epidemiology 22: 632-636.

What was done
For the five-year period 1 July 1985 to 30 June 1990, the authors investigated the effects of extremes of temperature and rainfall, as well as intermediate levels, on the number of coronary events, both fatal and non-fatal, reported in the Hunter Region of New South Wales, Australia, which is located on the east coast of the country about 150 km north of Sydney. "Daily temperature and rainfall," in their words, "were taken as indicators of acute effects of weather and the month when an event occurred was used to indicate longer-term or seasonal effects."

What was learned
With respect to seasonal effects, the authors report that "fatal coronary events and non-fatal definite myocardial infarction were 20-40% more common in winter and spring than at other times of year." With respect to daily temperature effects, they found that "rate ratios for deaths were significantly higher for low temperatures," noting that "on cold days coronary deaths were up to 40% more likely to occur than at moderate temperatures." Effects of humidity and rainfall were negligible.

What it means
The authors say their data "support the theory of increased risk of coronary mortality when temperatures are unusually low," and that "avoiding temperature extremes could contribute to reduction in annual peaks in coronary events," which occur during the colder part of the year. Clearly, therefore, a little global warming would likely reduce the incidence of heart attacks in this part of Australia.

Reviewed 13 August 2003