Heat wave impact on mortality in Pudong New Area, China in 2013

Background: In 2013 southeast China suffered from an unusual high temperature, which had broken the heat records in the past 141 years. Few studies have examined the impact of heat waves on mortality in Asia.

Objective: To estimate the impact of the heat wave in 2013 on mortality among the registered permanent residence population and identify susceptible subpopulations in Pudong New Area.

Methods: To model the relationship between the maximum temperature and mortality, a quasi-poisson generalized additive model was applied using data from 1 January 2008 to 15 June 2013. Extrapolating the model the estimated daily expected number of deaths was calculated over the period of 16 June 2013 to 15 September 2013.

Results: There were four heat waves in 2013, causing 167 (95% CI: 46-280) excess deaths in all-cause mortality, corresponding to an excess mortality of 10.51%. After the first two heat waves, the cumulative excess death counts gradually reduced to the level before the start of the heat waves. In contrast, the cumulative excess death numbers increased rapidly during the last two heat waves, without decreasing after the heat waves. Females (male: 10.43%, female: 11.79%) and people aged ≥ 80 years old (excess deaths were 129 (95% CI: 47-203) and excess mortality was 16.64%) were strongly affected by the heat waves. The excess mortalities of cardiovascular and respiratory disease were 22.34% and 20.68% respectively, which were higher than that of all-cause deaths.

Conclusions: The 2013 heat wave had a significant impact on mortality even after the considered "mortality displacement". Females and people aged ≥ 80 years old were significantly vulnerable to the heat waves. The observed excess mortalities of cardiovascular and respiratory disease were higher than all-cause deaths. These results could provide scientific evidences for policy makers to frame heat wave-related prevention measures, which may help in reducing the mortality.