A new study suggests a potentially deadly link between the global climate crisis and the increasing rates of death and disability from stroke.
In a new study published today, researchers say the majority of strokes observed over 30 years were attributed to lower-than-optimal global temperatures. The researchers also noted a rise in strokes linked to higher-than-optimal temperatures. Lower temperatures can cause blood vessels to constrict, elevating blood pressure — a known risk factor for stroke. Conversely, higher temperatures may induce dehydration, impacting cholesterol levels and reducing blood flow, factors that can predispose individuals to stroke.
The researchers analyzed health records spanning three decades from more than 200 countries and territories. They examined stroke-related mortality and disability attributed to non-optimal temperatures across different regions, countries, age groups, and genders. The findings are published in the journal Neurology, the medical journal of the American Academy of Neurology.
Quan Cheng, PhD, of Xiangya Hospital Central South University in Changsha, China, the study’s lead author, said in a statement that dramatic shifts in global temperatures in recent years have affected human health, causing widespread concern. “Our study found that these changing temperatures may increase the burden of stroke worldwide, especially in older populations and areas with more health care disparities,” Cheng said.
While the study does not establish a causal relationship between climate change and stroke, it highlights an association between non-optimal temperatures and the rise in stroke-related mortality and disability. The researchers observed that temperatures deviating from the optimal range, either too high or too low, were increasingly associated with death and disability due to stroke. The study did not account for other established risk factors such as high blood pressure and high cholesterol levels.
In 2019 alone, there were 521,031 stroke deaths linked to non-optimal temperatures, along with 9.4 million disability-adjusted life years due to stroke associated with temperature deviations. Disability-adjusted life years quantify the years of life lost due to premature death and years lived with illness. The study found that the majority of stroke deaths — 474,002 in total — were associated with low temperatures. Furthermore, the rate of stroke-related mortality due to temperature fluctuations was higher among male participants compared to females.
Regional analysis indicated that central Asia exhibited the highest death rate from stroke linked to non-optimal temperatures, with 18 per 100,000. At the national level, North Macedonia recorded the highest death rate, with 33 per 100,000. Cheng emphasized the need for further research to understand the impact of temperature changes on stroke and to devise targeted solutions addressing health disparities. He added, “Future research should aim to reduce this threat by finding effective health policies that address potential causes of climate change, such as the burning of fossil fuels, deforestation, and industrial processes.”
The study comes as the European Court of Human Rights ruled on Tuesday that the Swiss government had violated the human rights of its citizens by failing to adequately address climate change. This landmark decision, in favor of over 2,000 Swiss women who brought the case, sets a precedent for future climate-related lawsuits and is expected to resonate across Europe and beyond, potentially emboldening more communities to challenge governments on climate action.
The ruling comes amidst a surge in climate litigation globally, underscoring the increasing urgency of addressing climate change through legal avenues. While the court’s decision specifically highlights Switzerland’s failure to meet its own emissions targets and implement sufficient climate policies, it sends a broader message about governments’ legal obligations to combat climate change to protect human rights. The verdict is likely to spur further legal action at both national and international levels, signaling a growing trend of citizens holding governments accountable for climate failures.
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