Causes and risk factors

Certain medical conditions are associated with an increased risk of stroke. These include:

  • high blood pressure,
  • heart conditions,
  • diabetes,
  • raised blood cholesterol,
  • excessive blood loss and
  • hereditary blood clotting conditions.

Other factors known to increase the likelihood of stroke are lifestyle factors such as:

  • smoking,
  • high alcohol intake,
  • obesity and
  • having an inactive lifestyle.

Stroke is also more common in people of African-Caribbean and South Asian origin. The risk of having a stroke increases with age, “Although most people who have a stroke are over 65, around a quarter of strokes happen in people who are younger,” (Stroke Association). See 'When stroke happens at a young age'.

Some people said how having the stroke had been a complete surprise because they had not known they had high blood pressure or diabetes. Some people felt they had been fit and healthy before the stroke and that it had actually been caused by other conditions, for example heart conditions or a stroke which occurred during a surgical procedure, although very few strokes occur in this way. 

Lifestyle - alcohol, smoking, diet and exercise.

Some people had been told by their doctor that smoking had been a major cause of their stroke. Others who had given up smoking over 20 years ago or had been light smokers wondered whether this may have contributed but some thought that it probably had not. The risk of stroke declines rapidly after stopping smoking, however even passive smoking is linked to stroke.

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A few people had been heavy drinkers and thought that this in combination with other factors such as smoking, poor diet and stress had contributed to them having a stroke. Drinking to excess, and particularly binge drinking, can raise blood pressure and cause stroke although research suggests that moderate drinking of around 1-2 units a day especially of red wine may reduce the risk of stroke.

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High fat diet, being overweight and lack of exercise were often seen as contributing to the stroke. People realised that high fat diet can be linked to high cholesterol but some were not aware that you do not have to be overweight to have raised cholesterol. High cholesterol is sometimes hereditary.

Two people had been abroad in a hot country and wondered whether their strokes had been partially due to over activity and dehydration. Current medical evidence suggests that dehydration can be linked to increased risk of stroke, but increased activity is not. 

Not getting health checked

A few people thought that not seeing their doctor and getting their health checked had been responsible for them having a stroke. Men in particular felt that this was a common male failing although women also said that they should have had their health checked.

One man, who had suffered a heart attack a few years earlier, regretted that he had not changed his lifestyle or attended follow up visits and felt that this was a major reason for his stroke. 

High blood pressure 

High blood pressure is a common cause of stroke. Whilst some people had been aware that they had high blood pressure others had not been aware because there were often no symptoms. They encouraged other members of their family and friends to get their blood pressure checked particularly if they were over 50. 

The wife of a man of south Asian origin explained that high cholesterol and high blood pressure ran in the family and that her brother who is a doctor had advised her husband's family to get checked as they may also be at risk of stroke.

Family history

Some of the people that we spoke to had close relatives who had also had a stroke and wondered whether there may be a genetic link. Stroke does run in families and some specific genetic conditions can also cause stroke.

One young woman that we spoke to had a rare clotting disorder called Factor V Leiden - her father and cousin also have the condition and now take medication to prevent a stroke. She thought that smoking and taking the pill may have increased her risk of having a stroke. Another woman who had a brain haemorrhage due to arterial venous malformation, which is sometimes hereditary, worried that other people in her family may be at risk. 


Some people thought that having a stressful job or busy lifestyle had contributed to their stroke. Others wondered whether their stroke had been triggered by a specific stressful event. Strokes can very occasionally be caused by one off stressful events but the long term impact of stress on the risk of stroke is not clear and the effects may be due the links between stress and lack of exercise and other high risk lifestyle factors. 

Heart and other vascular conditions

Blood clots that cause a stroke sometimes originate because of heart conditions or during operations on the heart, such as bypass operation or repair of a heart valve. 

A few people had been found to be suffering from a condition known as atrial fibrillation where changes in the electrical conducting system of the heart cause it to beat irregularly (arrhythmia). In the general population this is quite common and is a considerable risk factor for stroke. The erratic blood flow can lead to clots which can become lodged in the blood supply to the brain.

A few people had a stroke or TIA due to a narrowing of the arteries of the neck (carotid arteries) due to atherosclerosis (furring up of the arteries). One woman, however, thought that a vigorous neck massage precipitated clotting in her carotid artery, and another woman had been told that this type of stroke can occur because of a sudden jerk to the neck. These are relatively rare causes of stroke.

Last reviewed August 2013
Last updated August 2011



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