November Severe stroke risk linked to high blood pressure, smoking, and irregular heartbeat

High blood pressure, smoking, and atrial fibrillation - a common irregular heartbeat - are associated with increased severity of stroke, according to new findings from the global INTERSTROKE study led by University of Galway in collaboration with McMaster University, Canada.

INTERSTROKE is one of the largest international studies on stroke risk factors, involving over 26,000 people across 32 countries, including almost 13,500 who had experienced their first stroke.

The study’s findings, published online in Neurology®, the medical journal of the American Academy of Neurology, underline the importance of managing modifiable stroke risk factors.

The study looked at how common risk factors, such as high blood pressure, relate to risk of severe stroke, and mild-moderate stroke, which is regarded a stroke that does not affecting your ability to walk independently.

Three risk factors - high blood pressure, smoking, and atrial fibrillation were linked to higher risk of severe stroke, compared to mild-moderate stroke.

Lead author Dr Catriona Reddin, researcher at University of Galway and Geriatric Medicine Specialist Registrar at Health Services Executive Ireland, said: “Stroke can cause disability or death, yet many risk factors can be managed with lifestyle changes or medication.  Our results show that controlling high blood pressure, along with managing atrial fibrillation and avoiding smoking, are especially importance in reducing the risk of severe stroke.”

The study’s key findings include:

• High Blood Pressure: Among participants, 74% of those with severe stroke had high blood pressure, compared to 72% with mild to moderate stroke. High blood pressure was associated with a 3.2 times higher likelihood of severe stroke. High blood pressure was associated with both severe and mild-moderate stroke.
• Atrial Fibrillation: 11% of people with severe stroke had atrial fibrillation, compared to 9% with mild to moderate stroke. People with atrial fibrillation were 4.7 times more likely to suffer a severe stroke. Atrial fibrillation was associated with both severe and mild-moderate stroke.
• Smoking: 30% of people with severe stroke were current smokers, with smoking doubling the likelihood of severe stroke. Smoking was associated with both severe and mild-moderate stroke.

Professor Martin O’Donnell, Professor of Neurovascular Medicine, Executive Dean of the College of Medicine, Nursing and Health Sciences at University of Galway, and Consultant Stroke Physician with Health Services Executive Ireland, co-leads the INTERSTROKE study, in partnership with Professor Salim Yusuf from the Population Health Research Institute at McMaster University, Canada.

Commenting on the findings, Professor O’Donnell said: “In the main publication from INTERSTROKE study, we reported on key risk factors for stroke. In the current paper, we report on whether these common risk factors have an impact on severity of stroke. Our findings further emphasis the critical importance of detecting and treating hypertension, to reduce the rates of severe stroke, which is of relevance in all regions of the world. This research highlights practical steps that individuals and healthcare providers can take to lower stroke severity risk.”

The INTERSTROKE study, conducted with a diverse range of participants from various geographical, ethnic, and cardiovascular backgrounds, continues to build understanding of preventable risk factors to inform stroke prevention strategies worldwide.

A series of findings have been released as part of the wider INTERSTROKE project and can be accessed here. 

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