Where does this news come from?

Researchers from 15 universities gathered data from 13 countries on temperatures and death rates from 1985 to 2012. They wanted to determine which temperatures are the most deadly. The countries for which temperature data was collected are Australia, Brazil, Canada, China, Italy, Japan, South Korea, Spain, Sweden, Taiwan, Thailand, the United Kingdom, and the United States. In total, almost 75,000,000 deaths were recorded.

Temperature data were divided into percentiles, with temperatures below the 2.5th percentile and above the 97.5th percentile considered extreme. Researchers then looked at how many deaths occurred and at what temperature and found that 20 times more people die in cold climates than in hot climates (1). For each participating country, the optimal temperature was determined; for example, for the United Kingdom it ranged between 15.9 and 19.5 degrees Celsius.

Researchers suggested that cold weather may be more stressful on the immune system and circulatory system.

Fountain

(1) Gasparrini A, Guo Y, Hashizume M, et al. Risk of mortality attributable to high and low ambient temperature: a multi-country observational study. The lancet. Published online May 20, 2015

How should you interpret this news?

These are pure calculations that do not take into account factors such as pollution, nutrition, age, income class, etc. It is not surprising that more deaths occur in bad weather, because extreme temperatures are less frequent in the participating countries. It makes sense that more people die in moderate temperatures when they prevail. The researchers themselves determine what extreme temperatures are.

Conclusion

More people would die during periods of bad weather than during periods of extreme heat and cold. This makes sense, since the countries involved in this study have many more days with moderate temperatures.

References

http://www.nhs.uk/news/2015/05May/Pages/Mild-cold-more-deadly-than-heat-waves-or-very-cold-snaps.aspx