Background
Although studies have provided estimates of premature deaths attributable to either heat or cold in selected countries, none has so far offered a systematic assessment across the whole temperature range in populations exposed to different climates. We aimed to quantify the total mortality burden attributable to non-optimum ambient temperature, and the relative contributions from heat and cold and from moderate and extreme temperatures.
Discussion
Our findings show that temperature is responsible for advancing a substantial fraction of deaths, corresponding to 7·71% of mortality in the selected countries within the study period.
Most of this mortality burden was caused by days colder than the optimum temperature (7·29%), compared with days warmer than the optimum temperature (0·42%).
Furthermore, most deaths were caused by exposure to moderately hot and cold temperatures, and the contribution of extreme days was comparatively low
http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(14)62114-0/fulltext