Higher hourly heat exposure tied to acute ischemic stroke risk

 FYI.

Higher hourly heat exposure tied to acute ischemic stroke risk

Key takeaways:

• Higher hourly heat exposure conferred elevated risk for acute ischemic stroke.
• The findings could help in developing public policies to combat the risks of climate change.

High hourly heat exposure was associated with elevated risk for acute ischemic stroke, researchers reported in JAMA Network Open.

“A nationwide case-crossover investigation based on individual acute ischemic stroke onset time is imperative to quantify the association between acute ischemic stroke onset and hourly ambient heat exposure,” Xinlei Zhu, MS, from the School of Public Health, Key Lab of Public Health Safety of the Ministry of Education and National Health Commission Key Lab of Health Technology Assessment, Fudan University, Shanghai, and colleagues wrote. “As one of the world’s largest middle-income countries, China has the highest stroke burden and is among the most vulnerable to global climate change. Accordingly, in the present time-stratified case-crossover analysis, we aimed to evaluate the association between hourly high ambient temperature and the onset of acute ischemic stroke using a nationwide registry of acute ischemic stroke. Additionally, we assessed possible association modifiers, such as geographic region, smoking, alcohol drinking, sex, age and history of other disease.”

Higher hourly heat exposure conferred elevated risk for acute ischemic stroke. Image: Adobe Stock

The analysis involved 82,455 patients with acute ischemic stroke (mean age, 66 years; 63% men) included in a national registry of more than 200 stroke centers in China who were hospitalized in the warm seasons from 2019 to 2021.

The researchers found that a monotonically increasing risk for acute ischemic stroke onset was associated with higher temperatures, and that the excess acute ischemic stroke risk occurred immediately at lag 0 hours and persisted for 10 hours.

Compared with the reference temperature of 12.1°C, the cumulative OR over lag of 0 to 10 hours of acute ischemic stroke onset for extremely high temperatures (33.3°C) was 1.88 (95% CI, 1.65-2.13), Zhu and colleagues wrote.

The exposure-response curve was steeper in Northern institutions (OR = 1.8; 95% CI, 1.53-2.11) compared with Southern institutions (OR = 1.57; 95% CI, 1.31-1.87; P for z score = .27), according to the researchers.

The ORs were greater among men than women and for those with a history of dyslipidemia or atrial fibrillation compared with those without a history, but the differences were not significant, Zhu and colleagues wrote.

The study “presents robust evidence of high temperature as an important factor in increased risk of acute ischemic stroke onset,” the researchers wrote. “The results add valuable insights to the adverse cardiovascular outcome of climate warming and may benefit the formulation of public health strategies to reduce cerebrovascular risk associated with high ambient temperature under global warming. Additionally, the findings underscore the ongoing need for public health agencies to advocate for interventions that mitigate heat exposure and bolster cooling measures, particularly among populations at high risk for acute ischemic stroke.”

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Sources/Disclosures

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Source:

Zhu X, et al. JAMA Network Open. 2024;doi:10.1001/jamanetworkopen.2024.0627.

Disclosures: The authors report no relevant financial disclosures.

Read more about

acute ischemic stroke

public health

climate change

heat-related illness