Environmental Changes and Stroke Risk
Environmental changes driven by climate change, such as extreme temperatures, sudden temperature fluctuations, humidity, air pressure variations, wildfires, dust storms, and sandstorms, may be linked to an increased risk of stroke, according to recent research. Scientists collaborating with the World Stroke Organization have analyzed published studies that explore the connection between stroke and climate-related environmental changes.
Their findings suggest that a more unstable climate could heighten the risk of both experiencing a stroke and dying from one. However, researchers emphasize that most of the evidence indicates associations rather than direct causation. Despite this, they note that the overall pattern of results is consistent and biologically plausible.
Anna Ranta, a senior lead author of the review and researcher at the Department of Medicine at the University of Otago in Wellington, New Zealand, explained that hot temperatures can lead to dehydration, which thickens the blood and increases the risk of blocked blood vessels. Additionally, changes in humidity and air pressure can elevate blood pressure, a significant contributor to strokes.
The Impact of Weather Extremes
Weather extremes often occur simultaneously, such as extreme heat and drought, or cold, humidity, and wind. These combinations can have an additive effect, further increasing the risk of stroke and death. The study highlights that certain groups are more vulnerable, including older adults, individuals with metabolic disorders, and those residing in colder or lower-income areas, where both extreme cold and heat can significantly contribute to the stroke burden.
The World Stroke Organization has also identified air pollution as a major factor in stroke risk. Their latest Global Stroke Fact Sheet reveals that environmental risk factors, primarily air pollution and lead exposure, account for approximately 37% of the global stroke burden.
Air Pollution and Stroke
Air pollutants, particularly particulate matter, enter the bloodstream through the lungs and cause damage to blood vessel walls. This damage can result in blocked or ruptured brain arteries, leading to a stroke. Since climate change and air pollution share a common source—the burning of fossil fuels—reducing greenhouse gas emissions could help mitigate climate-related stroke risks and protect brain health.
The Global Burden of Stroke
Stroke is the third leading cause of death and disability worldwide. In 2021, there were 11.9 million new cases, and one in four adults faces a lifetime risk of stroke, according to the World Health Organization. As climate change continues to impact the environment, understanding and addressing its effects on public health becomes increasingly critical.
