Stroke: Can lifestyle changes trump genetic risk?

Strokes happen when an obstruction restricts the blood supply to the brain, and so the brain does not receive enough oxygen. A person’s genetic makeup and their lifestyle both influence their risk of stroke, but which is more important?

According to the Centers for Disease Control and Prevention (CDC), every 40 seconds, a person in the United States has a stroke, and more than 795,000 people experience this cardiovascular event each year.

So far, specialists have identified a range of modifiable and nonmodifiable factors that influence an individual’s risk of stroke.

Thus, on the one hand, a person may be predisposed to such cardiovascular events due to their genetic makeup. At the same time, numerous lifestyle factors — such as smoking or drinking habits, level of physical activity, and diet — also affect stroke risk.

But which factors are more critical, and to what extent can we prevent stroke?

We may now, finally, have an answer to this question, thanks to a new study that specialists from numerous prestigious institutions across Europe — including the University of Cambridge in the United Kingdom, the Karolinska Institutet in Stockholm, Sweden, and the German Center for Neurodegenerative Diseases in Bonn, Germany — have conducted.

Together, the scientists report their findings in a study paper that appears in The BMJ and whose first author is Loes Rutten-Jacobs.

According to the authors, the results “highlight the potential of lifestyle measures to reduce risk of stroke across entire populations, even in those at high genetic risk of stroke.”

Which factors are more important?

In the current study, the researchers analyzed the genetic information of 306,473 participants from the U.K., which they sourced via the UK Biobank. All the individuals were between 40 and 73 years old, with no history of heart attack or stroke.

The investigators looked for 90 gene variants that scientists know are associated with stroke risk. Also, they determined whether each participant was leading a healthful lifestyle by looking at four factors — namely:

  • whether or not they smoked
  • whether or not they consumed a diet rich in fish, fruit, and vegetables
  • whether they had a body mass index (BMI) below 30, indicating that they were not overweight
  • whether they exercised on a regular basis

Over an average follow-up period of 7 years, the researchers then collected hospital and death records to discover occurrences of stroke.

Overall, they noted that in terms of both genetic and lifestyle risk, men tended to be more predisposed to stroke than women.

Furthermore, stroke risk was 35 percent higher in people with a high genetic predisposition versus those with a low genetic predisposition, regardless of their lifestyle choices.

At the same time, people who led an unhealthful life had a 66 percent higher risk of stroke than those who made healthful lifestyle choices. The increase was the same across all the genetic risk categories.

The most critical lifestyle factors that swayed a person’s risk of stroke appeared to be a smoking habit and whether or not they were overweight, the authors observed.

Finally, people who had both a high genetic risk of stroke and led an unhealthful life had more than twice as high a risk of stroke compared with peers who had a low genetic risk and made healthful lifestyle choices.