[Association between high air temperature and mortality in summer: A multi-city analysis in China]

Objective: To understand the associations between changes of high air temperature and mortality in summer in 31 cities in China. Methods: Daily mortality and meteorological data in 31 cities in China from January 1, 2008 to December 31, 2013 were collected. Distributed lag nonlinear model was used to evaluate the association between high air temperature change and mortality in early summer and late summer after controlling for the long-term trend and the effect of "day of week" . Results: The relative risk of high air temperature on mortality was higher in early summer, with relative risk in the range of 1.08-2.14 in early summer and 1.03-1.67 in late summer. In early summer, the influence of high temperature on mortality was mainly below 5(th) of percentile and above 50(th) of percentile, while in late summer it was mainly above 95(th) of percentile. The lag effect of high air temperature on mortality in early summer was 6 days, while the lag effect in late summer was only about 2 days. Conclusions: Association existed between high air temperature and mortality. The influence of high air temperature on mortality in early summer was stronger than that in late summer. It is necessary to take targeted protection measures.