Extremely cold and hot temperatures increase the risk of ischaemic heart disease mortality: epidemiological evidence from China
- Yuming Guo1,2,
- Shanshan Li3,
- Yanshen Zhang4,
- Ben Armstrong5,
- Jouni J K Jaakkola6,
- Shilu Tong7,
- Xiaochuan Pan1
- 1Department of Occupational and Environmental Health, School of Public Health, Peking University, Beijing, China
- 2School of Medicine, The University of Queensland, Brisbane, Australia
- 3Department of Epidemiology and Biostatistics, School of Population Health, The University of Queensland, Brisbane, Australia
- 4Center for Environmental Risk and Damage Assessment, Chinese Academy for Environmental Planning, Beijing, China
- 5Department of Social and Environmental Health Research, London School of Hygiene & Tropical Medicine, London, UK
- 6Center for Environmental and Respiratory Health Research, Institute of Health Sciences, University of Oulu, Oulu, Finland
- 7School of Public Health and Social Work and Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia
- Correspondence to Dr Yuming Guo, School of Medicine, The University of Queensland, Brisbane, QLD 4006, Australia; Professor Xiaochuan Pan, Department of Occupational and Environmental Health, School of Public Health, Peking University, Beijing 100191, China; firstname.lastname@example.org
- Received 1 June 2012
- Revised 4 October 2012
- Accepted 6 October 2012
- Published Online First 13 November 2012
Objective To examine the effects of extremely cold and hot temperatures on ischaemic heart disease (IHD) mortality in five cities (Beijing, Tianjin, Shanghai, Wuhan and Guangzhou) in China; and to examine the time relationships between cold and hot temperatures and IHD mortality for each city.
Design A negative binomial regression model combined with a distributed lag non-linear model was used to examine city-specific temperature effects on IHD mortality up to 20 lag days. A meta-analysis was used to pool the cold effects and hot effects across the five cities.
Patients 16 559 IHD deaths were monitored by a sentinel surveillance system in five cities during 2004–2008.
Results The relationships between temperature and IHD mortality were non-linear in all five cities. The minimum-mortality temperatures in northern cities were lower than in southern cities. In Beijing, Tianjin and Guangzhou, the effects of extremely cold temperatures were delayed, while Shanghai and Wuhan had immediate cold effects. The effects of extremely hot temperatures appeared immediately in all the cities except Wuhan. Meta-analysis showed that IHD mortality increased 48% at the 1st percentile of temperature (extremely cold temperature) compared with the 10th percentile, while IHD mortality increased 18% at the 99th percentile of temperature (extremely hot temperature) compared with the 90th percentile.
Conclusions Results indicate that both extremely cold and hot temperatures increase IHD mortality in China. Each city has its characteristics of heat effects on IHD mortality. The policy for response to climate change should consider local climate–IHD mortality relationships.