The world endured its hottest summer on record in 2024, and the transition to fall brought devastation from multiple hurricanes in the U.S. The growing effects of climate change are widespread and becoming more severe. Now, new research is making it apparent that my field of neurointerventional surgery must confront the growing and deadly link between climate change and an increase in stroke.
Just last month, the latest stroke update from the Global Burden of Disease, Injuries, and Risk Factors (GBD) study in The Lancet Neurology reported that “rises in ambient temperature (including heatwaves) and climate change are associated with increased stroke morbidity and mortality.”
Earlier this year, another study published in Neurology found that, in 2019, more than half a million people died due to strokes that were linked to extreme temperatures (including both extreme highs and lows). From the study, “Globally, low temperature (deaths 474,002, 95% UI 355,077–606,537; DALYs 8,357,198, 95% UI 6,186,217–10,801,911) contributed more to stroke deaths and DALYs [disability-adjusted life years] than high temperature (deaths 48,030, 95% UI 5,630–104,370; DALYs 1,089,329, 95% UI 112,690–2,375,345) in 2019.”
While research on the climate change-stroke connection focuses mostly on extreme temperatures and air pollution, we know that service disruptions due to other extreme weather events — like the hurricanes and flooding that caused so much devastation in the Southeastern U.S. — will ultimately lead to treatment delays and a potential increase in death and disability from stroke. In fact, in preparation for the extreme effects of Hurricane Milton, first responders were forced to suspend answering 911 calls.
As with so many health issues, the poorer a patient is, the more vulnerable they are. In these studies, the connection between climate change and stroke mortality was stronger in low-income countries than high-income countries. Moreover, emerging research at the intersection of environmental justice and medicine is shedding light on comparable injustices being experienced here in the U.S., further exacerbating serious health disparities in stroke care.
Specifically, research released at the Society of NeuroInterventional Surgery’s annual meeting this summer found that worsening air quality and temperature extremes in the U.S. are linked to increased stroke burden, especially among those with lower incomes and a lack of health resources.
Researchers found that stroke prevalence was higher in areas with higher climate vulnerability scores, especially in the Southeast and the Midwest. Across the entire country, stroke incidence was 1.5 times higher in areas with the highest climate vulnerability scores (in the top 10th percentile in the Climate Vulnerability Index) compared to areas with lower scores (in the 50th percentile). Rural areas were especially likely to have high levels of combined climate vulnerability and stroke prevalence.
What this growing body of research makes clear is climate change is altering what it means to be “at risk” for a stroke. And to best serve potential patients, the fields of stroke and neurointerventional medicine and public health need to adapt our approach to stroke care.
Today, much of the public-facing stroke messaging is focused on prevention, and while stroke prevention is important, stroke education cannot end there. Focusing on risk factors alone can leave those who fall outside of the “high-risk” category unprepared. Plus, now we know the risk factors are shifting. Strokes affect people of all ages, including children, as well as those who have a healthy diet and have no family history of stroke.
The authors of the GBD stroke study conclude, “In summary, our study findings continue to point out that currently used stroke prevention strategies are not sufficiently effective to halt, let alone reduce, the fast-growing stroke burden.”
I agree. We need to approach the reduction of the global stroke burden from multiple angles.
A common barrier to better care is that many people are unfamiliar with stroke symptoms. According to a recent omnibus survey, around two-thirds of adults (63%) say they would know if they were having a stroke, but only 16% of adults can correctly identify common stroke symptoms, and around 1 in 10 (11%) get all these common symptoms incorrect.
Healthcare providers need to share the BE FAST acronym with every patient. It is a critical tool to assess stroke symptoms: Balance loss, Eyesight changes, Facial drooping, Arm weakness, Speech difficulty, Time to call 911.
The survey also found that less than half of American adults would call 911 for a stroke. That statistic points to a huge gap in public understanding, one that can be the difference between life and death.
Nearly 2 million brain cells die every minute a severe stroke goes untreated. The longer a patient’s treatment is delayed, the greater the impact of a stroke, including the potential for severe disability and death. Yet, not realizing it’s time-sensitive, too many people drive themselves to the hospital or have a family member or friend drive them instead of calling 911. Our patients need to understand that even one, “mild” symptom of stroke is a reason to call 911.
So many of us feel powerless to mitigate the effects of climate change, but stroke is one place where public education can increase quality of life and survival. As we continue to learn more about the influence of climate change on stroke, we can take action now to reduce stroke death and disability by emphasizing to our patients, our loved ones, and the American public at large that stroke can happen to anyone at any age. Knowing BE FAST and seeking emergency treatment options immediately will save lives and reduce disability.
Johanna Fifi, MD, is a neuroendovascular surgeon at Mount Sinai Hospital in New York City and the president of the Society of NeuroInterventional Surgery. She serves as a professor of Neurosurgery, Neurology, and Radiology at the Icahn School of Medicine at Mount Sinai and is the director of the Pediatric Neuroendovascular Program, associate director of the Cerebrovascular Center, and co-director of the Neuroendovascular Surgery Fellowship Program.
Disclosures
Fifi is a consultant for Medtronic, Cerenovus, Stryker, MIVI, and Microvention. She owns stock in Imperative Care.
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