Both heat and cold increase the risk of death in England and Wales, but rates vary by geographic location, according to a new study.
New risk estimates suggest that London and other urban areas had the highest rate of heat-related deaths.
While cold-related deaths were highest in the north of England, Wales and the south-west.
The researchers say the findings indicate that the impacts of both heat and cold were stronger in poorer areas.
They argue that understanding these patterns is important when it comes to designing public health policies to protect vulnerable groups.
Detailed mapping of health burdens can help identify high-risk areas and population subgroups.
Dr. Antonio Gasparrini, LSHTM
Each year in England and Wales, there were an average of almost 800 heat-associated excess deaths, and more than 60,500 cold-associated deaths between 2000 and 2019, the study found.
The study was led by researchers from the Center for Climate Change and Planetary Health at the London School of Hygiene and Tropical Medicine (LSHTM), in collaboration with the UK Health Security Agency and researchers from several European universities.
London had the highest rate of heat-related deaths, with 3.21 excess deaths per 100,000 people, which translates to 170 excess heat-related deaths each year.
The risk of death associated with cold was higher in the northeast of England and Wales, with a mortality rate of more than 140.45 deaths and 136.95 deaths per 100,000 people, respectively.
The study found that London had the lowest risk associated with low temperatures, with 113.97 deaths per 100,000 people (nearly 5,800 excess cold-related deaths each year).
Dr Antonio Gasparrini, Professor of Biostatistics and Epidemiology at LSHTM and lead author of the study, said: “This study offers a comprehensive assessment of the health impacts of heat and cold in England and Wales, and provides several epidemiological indicators for over 37,000 areas across the two countries.
“These include estimates of the optimal temperature range, as well as measures of impact such as excess heat and cold mortality.
“Detailed mapping of health burdens can help identify high-risk areas and population subgroups.
“In particular, the results showed that the impacts of both heat and cold were stronger in the most deprived areas.
“Understanding these patterns is a critical step in designing effective public health policies at the local and national levels and protecting vulnerable groups, especially during the current cost of living crisis.”
The findings showed that the impacts of cold and, to a lesser extent, of heat, were more frequent in disadvantaged areas.
In addition, older people were the most vulnerable to both heat and cold, with a risk of death over 85 years of age twice that of people aged 0 to 64 years.
The researchers call for specific policies and better adaptation strategies to prevent more serious health consequences from both heat and cold.
In the study, they looked at 10.7 million deaths that occurred in England and Wales between 2000 and 2019 in more than 37,473 small areas that include around 1,600 residents.
Dr. Pierre Masselot, researcher in epidemiology and environmental statistics at LSHTM and co-author of the study, said: “The results come at a critical time, as countries and communities face ever-increasing health impacts from climate change and they need to find effective ways to adapt to changes in temperature.
“The analytical framework also provides a flexible tool that can be adapted for future studies that aim to model temperature-related risks and impacts at the small-area level under different climate change scenarios.”
The authors note that while the research showed that excess death attributed to cold was significantly higher than that attributed to heat, these results should be interpreted with caution as more cold than hot days were recorded throughout the year.
Funded by the Medical Research Council and the EU’s Horizon 2020 Programme, the findings are published in The Lancet Planetary Health.