Do the causes of stroke vary across different races? Are brain aneurysms more common in Asians or Caucasians? DR SRIRAM NARAYANAN, Senior Consultant Vascular and Endovascular Surgeon at The Harley Street Heart & Vascular Centre, shares his insights.
Stroke can lead to paralysis, loss of independence, mobility challenges and even death. It’s the fifth leading cause of death amongst Caucasians and the number one cause in China. Here, in the melting pot of races that is Singapore, it’s the fourth leading cause of death. About four percent of adults over the age of 50 are likely to have a stroke.
50, did I say? Yes, indeed. There is a growing trend worldwide for young adults in their forties and fifties to have a stroke. And, perhaps surprisingly, women across the world face a higher risk of stroke compared to men.
What are some common causes of stroke?
A stroke is the loss of blood supply to a part of the brain from a clot or by a bleed into the brain from a weak blood vessel wall. This leads to that part of the brain tissue dying from being starved of oxygen and nutrients. In about 15 percent of cases, strokes result from clots in the heart due to abnormal heart rhythms (atrial fibrillation) flying off to the brain. And here is where the differences between ethnic groups begin to show.
Causes of stroke – the Asian-Caucasian stroke paradox
Narrowing of the arteries that supply blood to the brain with cholesterol deposits tends to occur within the brain in Asians. Whereas in Caucasians, it typically happens in the carotid arteries at the neck. These are the sites where the clots form and block the blood flow to the brain. Ultrasound and MRI scan studies also show that the structure of the cholesterol deposits, also called plaques, in the neck carotid arteries is very different between the races. About half of all Caucasians who have a stroke have a “high-risk” plaque structure. That’s compared to only 16 percent of ethnic Chinese patients.
However, vessel wall weakening that leads to the wall ballooning out (brain aneurysms) and bleeding within the brain occurs much more frequently in Asians. An accurate generalisation would be to say that Caucasian strokes are caused more by cholesterol plaques in the neck arteries. Meanwhile, Asian strokes are caused more by blockages and bleeding within the brain itself.
What does this mean for stroke risk and screening?
The best way to treat a stroke is to try preventing it from happening – by screening the circulation and controlling, or even reversing, any underlying conditions. Stroke risk in Caucasians is more easily identified with a neck carotid artery ultrasound scan and minimised by aggressive management of any cholesterol-related problems. Asians, meanwhile, require careful control of blood pressure and diabetes, as well as early identification of brain aneurysms and narrowing of blood vessels in the brain through a CT or MRI scan.
Ideally, stroke risk screening should assess the neck and brain arteries, cholesterol levels, diabetes and blood pressure as well as identify any abnormal heart rhythms. Early treatment of any identified conditions is crucial. After all, your circulation is your lifeline.
The Harley Street Heart & Vascular Centre (Gleneagles Hospital)
#02-38/41 Annexe Block, 6A Napier Road
6472 0503 | WhatsApp 8822 8164
circulation@harleystreet.sg | vascular.harleystreet.sg/circulation-screening
This article about causes of strokes, brain aneurysms and stroke prevention first appeared in the February 2025 edition of Expat Living. You can purchase the latest issue or subscribe so you never miss a copy!
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