Climate change poses grave threat to brain health: study

A team of researchers led by University College London (UCL) has sounded the alarm over the potential impact of climate change on the health of people with brain conditions. 

In a new research published in The Lancet Neurology journal, the team emphasizes the urgent need to understand and address this issue to preserve the well-being of those affected and prevent widening inequalities.

Climate change aggravates brain conditions

After reviewing 332 papers published worldwide between 1968 and 2023, the researchers, led by Professor Sanjay Sisodiya from the UCL Queen Square Institute of Neurology, expect the scale of the potential effects of climate change on neurological diseases to be substantial.

The study considered 19 different nervous system conditions, including stroke, migraine, Alzheimer's, meningitis, epilepsy, and multiple sclerosis, as well as several serious psychiatric disorders such as anxiety, depression, and schizophrenia.

"There is clear evidence for an impact of the climate on some brain conditions, especially stroke and infections of the nervous system," said Professor Sisodiya, who is also the Director of Genomics at the Epilepsy Society and a founding member of Epilepsy Climate Change.

The researchers found that extremes of temperature, both low and high, as well as greater temperature variation throughout the day, especially when these measures were seasonally unusual, affected brain diseases. Notably, higher nighttime temperatures can disrupt sleep, which is known to aggravate various brain conditions.

The study revealed an increase in admissions, disability, or mortality resulting from strokes during periods of higher ambient temperatures or heatwaves. People with dementia were also found to be susceptible to harm from temperature extremes and adverse weather events, as cognitive impairment can limit their ability to adapt their behaviour to environmental changes.

Risk awareness lowered by frailty

"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," the researchers said, adding that this susceptibility is compounded by frailty, multimorbidity, and psychotropic medications.

Furthermore, the incidence, hospital admissions, and mortality risk for many mental health disorders were associated with increased ambient temperatures, daily fluctuations in temperature, or extreme hot and cold temperatures.

As adverse weather events increase in severity and global temperatures rise, populations are being exposed to worsening environmental factors that may not have been severe enough to affect brain conditions in some of the earlier studies reviewed.

Professor Sisodiya emphasized the importance of ensuring that research remains up-to-date and considers not only the present state of climate change but also future projections, noting that few studies have estimated health consequences on brain diseases under future climate scenarios, making planning challenging.

"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," he said. "But there are actions we can and should take now."

The research was funded by the Epilepsy Society and the National Brain Appeal Innovation Fund, underscoring the urgency and significance of this issue for the medical and scientific communities, as well as policymakers and the general public.