A new study has found that a healthy lifestyle reduces the risk of stroke even in those who are at high genetic risk.

A stroke occurs when the blood supply to the brain is interrupted, depriving it of oxygen. As a result, some of the brain cells die and others are damaged. Every year in Ireland, some 10,000 people suffer a stroke and 2,000 die as a result. Thousands more are left with stroke-related disabilities.

Stroke is a complex condition caused by both genetic and environmental factors, such as diet and lifestyle. A team of international researchers set out to determine whether following a healthy lifestyle could offset genetic risk.

They developed a genetic risk score based on data from over 306,000 men and women aged between 40 and 73 years, who had no history of stroke or heart attack.

The participants' adherence to a healthy lifestyle was based on four factors:
-being a non-smoker
-consuming a diet rich in fruit, vegetables and fish
-maintaining a healthy body weight
-exercising regularly.

They were followed up for an average of seven years and during this time, hospital and death records were used to identify any stroke events.

The researchers found that the risk of stroke was 35% higher among those considered at high genetic risk of stroke compared to those at low genetic risk. Those at high genetic risk would include people who have a family history of the disease, e.g. a parent or sibling who suffered a stroke.

However, the researchers also found that an unhealthy lifestyle was linked with a 66% increased risk of stroke compared with a healthy lifestyle, and this increased risk was present in all genetic risk groups.

The findings ‘highlight the potential of lifestyle measures to reduce risk of stroke across entire populations, even in those at high genetic risk of stroke', the researchers said.

Overall, those with a high genetic risk who also followed an unhealthy lifestyle were twice as likely to suffer a stroke compared to those with a low genetic risk who maintained a healthy lifestyle.

When it came to a healthy lifestyle, the two factors which were most associated with a reduced stroke risk were not smoking and not being overweight or obese.

The researchers acknowledged that this is an observational study, so no firm conclusions can be drawn, and the study only included Europeans.

However, they insisted that the large sample size enabled them to study the topic in detail and they believe the findings highlight the benefit for adhering to a healthy lifestyle for entire populations, independent of genetic risk.

Details of these findings are published in the British Medical Journal.