Is stroke in your genes?

A landmark international study of DNA samples from 520,000 people around the world, including 67,000 stroke patients, identified 22 new genetic risk factors for stroke. 

It is the largest genetic study of stroke to date, and could lead to stroke drug development, said Sudha Seshadri, M.D., co-author of the study published in Nature Genetics. It also has implications for dementia treatment.

“Understanding these newly identified risk factors for stroke should also enable us to find novel treatments for dementia,” said Dr. Seshadri, founding director of the university’s Glenn Biggs Institute for Alzheimer’s & Neurodegenerative Diseases. “Vascular disease in the brain—a series of strokes—can lead to dementia.”

The risk factors identified were for all major subtypes of ischemic stroke, the most common stroke that occurs when a blood vessel supplying the brain is blocked. 

The study found the largest correlation between genetic risk factors and blood pressure. Hypertension is a major risk factor for stroke. Vascular health is important for brain function. The brain does not store energy and requires a constant supply of blood and oxygen, as well as blood glucose.

“Any disruption can lead to cognitive problems,” Dr. Seshadri said. “The most obvious example of that is stroke. There is a deficit in the blood supply and that is associated with very obvious changes in cognitive function.”

In another study, Dr. Seshadri and colleagues from the Framingham Heart Study found a trend, over 30 years, of people showing signs of dementia later in life. This is partly attributable to greater control of blood pressure, she said.

 “We are looking at other causes, such as lower burden of multiple infections because of vaccination, and possibly lower levels of lead or other pollutants in the atmosphere,” she said. “Early education and nutrition might also play a role.”

Both studies illustrate the strong connection between heart health and brain function.

“What’s good for your heart also seems to be very good for your brain,” she said.