Climate change, and its effects on weather patterns and adverse weather events, is likely to negatively affect the health of people with brain conditions, researchers have warned.
The scientists argue that in order to preserve the health of people with neurological conditions, including Alzheimer’s and stroke, there is an urgent need to understand how climate change affects them.
As an example, they say that higher temperatures through the night can disrupt sleep, which could have a negative effect on some brain conditions.
There is clear evidence for an impact of the climate on some brain conditions, especially stroke and infections of the nervous system— Professor Sanjay Sisodiya
Following a review of 332 papers published across the world between 1968 and 2023, the team, led by Professor Sanjay Sisodiya of UCL Queen Square Institute of Neurology, said they expect the scale of the potential effects of climate change on neurological diseases to be substantial.
Professor Sisodiya, who is also director of genomics at the Epilepsy Society and a founding member of Epilepsy Climate Change, said: “There is clear evidence for an impact of the climate on some brain conditions, especially stroke and infections of the nervous system.
“The climatic variation that was shown to have an effect on brain diseases included extremes of temperature (both low and high), and greater temperature variation throughout the course of day – especially when these measures were seasonally unusual.
“Nighttime temperatures may be particularly important, as higher temperatures through the night can disrupt sleep.
“Poor sleep is known to aggravate a number of brain conditions.”
The researchers considered 19 different nervous system conditions, chosen on the basis of the Global Burden of Disease 2016 study, including stroke, migraine, Alzheimer’s, meningitis, epilepsy and multiple sclerosis.
They also analysed the impact of climate change on several serious but common psychiatric disorders including anxiety, depression and schizophrenia.
According to the findings, there was an increase in hospital admissions, disability or death as a result of a stroke in higher ambient temperatures or heatwaves.
The researchers also suggest that people with dementia are susceptible to harm from extremes of temperature and weather events such as flooding or wildfires, as their condition can impact their ability to adapt behaviour to environmental changes.
Writing in The Lancet Neurology, the researchers say: “Reduced awareness of risk is combined with a diminished capacity to seek help or to mitigate potential harm, such as by drinking more in hot weather or by adjusting clothing.
“This susceptibility is compounded by frailty, multimorbidity and psychotropic medications.
“Accordingly, greater temperature variation, hotter days and heatwaves lead to increased dementia-associated hospital admissions and mortality.”
The researchers say it is important to ensure that research is up to date and considers not only the present state of climate change but also the future.
Professor Sisodiya added: “The whole concept of climate anxiety is an added, potentially weighty, influence: many brain conditions are associated with higher risk of psychiatric disorders, including anxiety, and such multimorbidities can further complicate impacts of climate change and the adaptations necessary to preserve health.
“But there are actions we can and should take now.”
Funded by the Epilepsy Society and the National Brain Appeal Innovation Fund, the research is being published ahead of The Hot Brain 2: climate change and brain health event, which is led by Professor Sisodiya and jointly organised by UCL and The Lancet Neurology.
