Declining Diurnal Temperature Range Increases Human Longevity
Yang, J., Liu, H.-Z., Ou, C.-Q., Lin, G.-Z., Zhou, Q., Shen, G.-C., Chen, P.-Y. and Guo, Y. 2013. Global climate change: Impact of diurnal temperature range on mortality in Guangzhou, China. Environmental Pollution 175: 131-136.
Seeking to determine what role this phenomenon might have played among the inhabitants of Guangzhou, a subtropical city in China, Yang et al. examined the effects of DTR on cause-/age-/education-specific mortality during 2003-2010. This they did by combining a quasi-Poisson regression model with a distributed lag non-linear model to examine the effects of DTR on mortality, after first controlling for daily mean temperature, air pollutants, season and day of the week.
Based on their findings, the eight researchers report that "a 1°C increase in DTR at lag 0-4 days was associated with a 0.47% increase in non-accidental mortality." In addition, they report that stroke mortality was most sensitive to DTR, and that "females, the elderly and those with low education were more susceptible to DTR than males, the youth and those with high education, respectively."
As ever more researchers explore this phenomenon, it is becoming ever more clear that recent global warming - where the rise of the minimum temperature has occurred at a rate three times greater than that of the maximum temperature over most of the world (Karl et al., 1984, 1991) - has actually helped to reduce temperature-related deaths, not only by the means described here, but also due to the fact that extreme cold yearly kills far more people than extreme heat.
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Lim, Y.-H., Park, A.K. and Kim, H. 2011. Modifiers of diurnal temperature range and mortality association in six Korean cities. International Journal of Biometeorology 56: 33-42.