Over 7 million stroke deaths every year linked to air pollution, high blood pressure

A Lancet study has revealed that over 11 million stroke cases were reported in 2021, which has risen by 70% since 1990.

In Short

• With over 7 million deaths in 2021, stroke is the third leading cause of death globally
• For the first time, the study revealed the high contribution of air pollution to stroke
• Population growth and ageing are also major causes of this burden

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

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

It requires immediate medical attention for treatment.

A stroke, which is highly preventable, is tied to 23 modifiable risk factors, including air pollution, excess body weight, high blood pressure, smoking, and physical inactivity.

A Lancet study has revealed that new stroke cases 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, highlighted the urgent need for improved prevention strategies, with findings showing stroke incidence has risen by 70% since 1990, with 93.8 million people surviving strokes globally.

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

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

Between 1990 and 2021, the global stroke burden linked to high body mass index (BMI; up by 88%), high temperatures (up 72%), high blood sugar (up 32%), diet high in sugar-sweetened drinks (up 23%), low physical activity (up 11%), high systolic blood pressure (up 7%), and diet low in omega-6 polyunsaturated fatty acids (up 5%) increased substantially.

While population growth and ageing are major causes of this burden, rising environmental and behavioural risk factors like high body mass index (BMI), high blood sugar, and low physical activity play a major role.

Notably, age-standardized stroke rates have decreased globally since 1990, but improvements have stagnated since 2015, especially in Southeast Asia and Oceania.

For the first time, the study revealed the high contribution (on a par with smoking) of particulate matter air pollution to subarachnoid haemorrhage (fatal brain bleed).

The study emphasised that current prevention strategies are insufficient.

Researchers have called for new approaches to tackle modifiable risk factors such as obesity, air pollution, and unhealthy diets. With 84% of strokes linked to preventable factors, there's a clear opportunity to curb this rising crisis, the authors said.