Both heat and cold increase risk of death in England and Wales – but rates vary depending on geographical location, according to a new study.
New risk estimates suggest London and other urban areas had the highest heat-related death rate.
While cold-related deaths were highest in Northern England, Wales and the South West.
Researchers say the findings indicate that 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.
Each year in England and Wales, there were on average nearly 800 excess deaths associated with heat – and more than 60,500 associated with cold between 2000 and 2019, the study found.
The study was led by researchers from the Centre on Climate Change and Planetary Health at the London School of Hygiene & Tropical Medicine (LSHTM), in collaboration with the UK Health Security Agency and researchers from several European universities.
London had the highest heat-related death rate, with 3.21 excess deaths per 100,000 people, which translates to 170 heat-related excess deaths each year.
The risk of death associated with the cold was highest in the north east of England and Wales, with an excess death rate of 140.45 deaths and 136.95 deaths per 100,000 people, respectively.
The study found that London had the lowest risk associated with cold temperatures, with 113.97 deaths per 100,000 people (almost 5,800 cold-related excess deaths each year).
Dr Antonio Gasparrini, professor of biostatistics and epidemiology at LSHTM and lead author of the study, said: “This study offers a thorough evaluation of the health impacts of heat and cold across England and Wales, and provides several epidemiological indicators for more than 37,000 areas across the two countries.
“These include estimates of the optimal temperature range, as well as impact measures such as excess mortality for heat and cold.
“The detailed mapping of health burdens can help identify high-risk areas and population sub-groups.
“In particular, the results showed that the impacts of both heat and cold were stronger in more deprived areas.
“Understanding these patterns is a critical step to designing effective public health policies at 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 heat, were more prevalent in deprived areas.
Additionally, older people were the most vulnerable to both heat and cold, with death risk of over 85-year-olds twice as high as that of people aged zero to 64.
The researchers are calling for targeted policies and better adaptation strategies to prevent more severe health consequences from both heat and cold.
In the study, they analysed 10.7 million deaths which occurred in England and Wales between 2000 and 2019 across more than 37,473 small areas that include around 1,600 residents.
Dr Pierre Masselot, research fellow in environmental epidemiology and statistics at LSHTM and co-author of the study, said: “The results come at a critical time as countries and communities face increasing health impacts due to climate change and need to find effective ways to adapt to changing temperatures.
“The analytical framework also provides a flexible tool that can be adapted for future studies which aim to model temperature-related risks and impacts at small-area level under different climate change scenarios.”
The authors highlight 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 EU Horizon 2020 Programme, the findings are published in The Lancet Planetary Health.