Vulnerability to the mortality effects of warm temperature in the districts of England and Wales

Dr. James Bennett, Dr. Marta Blangiardo, Dr. Daniela Fecht, Prof. Paul Elliott and Prof. Majid Ezzati
MRC-PHE Centre for Environment and Health, School of Public Health, Imperial College

 

“It is well known that warm weather can increase the risk of cardiovascular and respiratory deaths, especially in elderly people” said Dr. James Bennett, the lead author of the study from the MRC-PHE Centre for Environment and Health at Imperial College London, “Climate change is expected to raise average temperatures and increase temperature variability, so we can expect it to have effects on mortality even in countries like the UK with a temperate climate.”

The study led by Professor Majid Ezzati at the Centre for Environment and Health, Imperial College assessed the risks associated with climate change and its impact to public health by quantifying the effects of warm temperatures on mortality from cardiorespiratory causes from local authority districts in England and Wales from 2001-2010. Bayesian spatial methods were applied using geo-coded mortality and environmental data provided by the Centre for Environment and Health's Small Area Health Statistics Unit (SAHSU) to conduct a national small-area analysis of the mortality effects of warm temperature for all 376 districts in England and Wales. The study identified the most vulnerable districts are those in London and the South/Southeast England with the odds of mortality from cardiorespiratory causes increasing up to 10% for 1C of warmer temperature. In comparison, no effects were detected with more resilient districts in the far North. Nationally, women above the age of 75 were more vulnerable to warm temperature than men, consistent with other studies of temperature. The study also predicted that 2C increase in temperature may result in 1,552 additional deaths, about half of which would occur in 95 districts. In the most vulnerable districts (for example, the deprived districts of Hackney and Tower Hamlets in London), the odds of dying would more than double on hot days such as those of August 2003. 

 

Professor Majid Ezzati explained “The reasons for the uneven distribution of deaths in warm weather need to be studied. It might be due to more vulnerable individuals being concentrated in some areas, or it might be related to differences at the community level, like quality of healthcare, that require government action. We might expect that people in areas that tend to be warmer would be more resilient, because they adapt by installing air conditioning for example. These results show that this isn’t the case in England and Wales. While climate change is a global phenomenon, resilience and vulnerability to its effects are highly local.”

 

The study also looked at the effects of winter temperature whereby a 2C increase in winter temperature would see 6,225 fewer deaths. Prof Ezzati explained that if climate change increased temperatures uniformly across both summer and winter, then the higher summer death rate would be more than offset by a cut in the rate of winter deaths. "But we don't want to be betting on [uniform warming] as a society," he said. "Climate change means more variable winters, not just uniformly warmer."

 

These high-resolution findings on health effects of temperature could potentially be used by health service planners to allow more effective response to emerging warm temperatures such as focusing local interventions in vulnerable districts. 

 

Lastly, by assessing vulnerability and resilience in relation to age, gender and selected community characteristics, this study hopes to encourage and initiate further investigations exploring other social factors such as the effects and quality of housing and healthcare access on vulnerability and resilience to emerging warmer temperatures. 

 

These findings are published in Nature Climate Change

http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2123.html

This research was funded by Medical Research Council, Public Health England, and the National Institute for Health Research (NIHR) Imperial Biomedical Research Centre.

 

Media coverage

The Guardian 
http://www.theguardian.com/environment/2014/mar/23/south-east-england-vulnerable-heatwave-deaths

Science Daily 
http://www.sciencedaily.com/releases/2014/03/140323152000.htm

BBC and ITV coverage
http://www.itv.com/news/london/2014-03-24/londoners-most-at-risk-of-dying-due-to-climate-change/

http://blueandgreentomorrow.com/2014/03/24/london-and-south-east-most-vulnerable-to-heatwave-related-deaths/

http://www3.imperial.ac.uk/newsandeventspggrp/imperialcollege/newssummary/news_24-3-2014-10-1-34