Short-Term Effects of the 2008 Cold Spell on Mortality in Three Subtropical Cities in Guangdong Province, China

Huiyan Xie,¹ Zhibin Yao,² Yonghui Zhang,³ Yanjun Xu,³ Xiaojun Xu,³ Tao Liu,^1,3 Hualiang Lin,^1,3 Xiangqian Lao,⁴ Shannon Rutherford,⁵ Cordia Chu,⁵ Cunrui Huang,^1,6 Scott Baum,⁵ and Wenjun Ma^1,3


¹Guangdong Provincial Institute of Public Health, Guangzhou, Guangdong, China; ²Guangdong Provincial Department of Health, Guangzhou, Guangdong, China; ³Center for Disease Control and Prevention of Guangdong Province, Guangzhou, Guangdong, China; ⁴School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China; ⁵Center for Environment and Population Health, School of Environment, Griffith University, Brisbane, Queensland, Australia; ⁶School of Public Health and Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia


Abstract

Background: Few studies have been conducted to investigate the impact of extreme cold events on mortality in subtropical regions.


Objective: In the present study we aimed to investigate the effects of the 2008 cold spell on mortality and the possibility of mortality displacement in three subtropical cities in China.


Methods: Daily mortality, air pollution, and weather data were collected from 2006 to 2009 in Guangzhou, Nanxiong (no air pollutants), and Taishan. We used a polynomial distributed lag model (DLM) to analyze the relationship between the 2008 cold spell and mortality. To observe the mortality displacement of the cold spell, we estimated the cumulative effects at lag0, lag0–6, lag0–13, lag0–20, and lag0–27 separately.


Results: During the 2008 cold spell, the cumulative risk of nonaccidental mortality increased significantly in Guangzhou [relative risk (RR) = 1.60; 95% CI: 1.19, 2.14] and Taishan (RR = 1.60; 95% CI: 1.06, 2.40) when lagged up to 4 weeks after the cold spell ended. Estimated effects at lag0–27 were more pronounced for males than for females, for respiratory mortality than for cardiovascular mortality, and for the elderly (≥ 75 years of age) than for those 0–64 years of age. Most of the cumulative RRs increased with longer lag times in Guangzhou and Taishan. However, in Nanxiong, the trend with cumulative RRs was less consistent, and we observed no statistically significant associations at lag0–27.


Conclusion: We found associations between the 2008 cold spell and increased mortality in the three subtropical cities of China. The lag effect structure of the cold spell varied with location and the type of mortality, and evidence of short-term mortality displacement was inconsistent. These findings suggest that extreme cold is an important public health problem in subtropical regions.


Key words: climate change, cold spell, mortality, subtropical cities, temperature. 


Environ Health Perspect 121:210–216 (2013). http://dx.doi.org/10.1289/ehp.1104541 [Online 31 October 2012]


Address correspondence to W. Ma, Guangdong Provincial Institute of Public Health, Center for Disease Control and Prevention of Guangdong Province, 176, Xin Gang Xi Rd., Guangzhou, China. Telephone: (8620) 84458530. E-mail: mwj68@vip.tom.com


This work was supported in part by the Adapting to Climate Change in China project, funded by the UK Department for International Development, the Swiss Agency for Development and Cooperation, and the UK Department for Energy and Climate Change. 


The authors declare they have no actual or potential competing financial interests.


Received 27 September 2012; Accepted 31 October 2012; Online 31 October 2012.