Despite stroke being preventable and treatable, the global burden of this condition has increased from 1990 to 2021, due to population growth, ageing, and increasing exposure to risk factors.

A stroke occurs when blood flow to a part of the brain is interrupted or reduced, depriving brain tissue of oxygen and nutrients. This can cause brain cells to die within minutes, leading to potential brain damage, disability, or death.

Immediate medical attention is required to treat this.

Stroke, which is entirely preventable, is associated with 23 modifiable risk factors, including air pollution, excess body weight, high blood pressure, smoking and physical inactivity.

A Lancet study showed that new cases of stroke reached 11.9 million in 2021, with 7.3 million stroke-related deaths, making stroke the third leading cause of death globally.

Research published in The Lancet Neurology, presented at the World Stroke Congress in 2024, highlights the urgent need for better prevention strategies, with findings showing that stroke incidence has increased by 70% since 1990, and 93.8 million people globally are stroke survivors.

Low- and middle-income countries are worst affected, accounting for more than three-quarters of global cases.

The number of years of healthy life lost due to stroke has also increased by 32%, making stroke the fourth leading cause of health loss globally.

Between 1990 and 2021, there were substantial increases in the global stroke burden associated with higher body mass index (BMI; increase by up to 88%), higher temperatures (increase by up to 72%), higher blood sugar (increase by up to 32%), diets high in sugar-sweetened beverages (increase by up to 23%), lower physical activity (increase by up to 11%), higher systolic blood pressure (increase by up to 7%), and diets low in omega-6 polyunsaturated fatty acids (increase by up to 5%).

While population growth and aging are the major causes of this burden, increasing environmental and behavioral risk factors such as high body mass index (BMI), high blood sugar, and low physical activity also play a major role.

Notably, age-standardised stroke rates have declined globally since 1990, but improvements have stagnated since 2015, particularly in Southeast Asia and Oceania.

For the first time, the study revealed a high contribution (equal to smoking) of particulate matter air pollution to subarachnoid hemorrhage (fatal brain bleeding).

The study highlighted that current prevention strategies are inadequate.

The researchers call for new approaches to tackle modifiable risk factors such as obesity, air pollution and unhealthy diets. The authors said 84% of strokes are linked to preventable factors, so there is a clear opportunity to stop this growing crisis.