Brain injury ‘increases risk of stroke’

Sustaining brain injury is associated with a significantly increased risk of ischemic stroke – and two or more head injuries elevates that risk even further, a new study shows.

A person experiencing traumatic brain injury (TBI), no matter how severe, can led to a heightened chance of experiencing ischemic stroke, research reveals. 

And the risk of stroke with two head injuries can be raised by as much as 94 per cent, the study team found. 

“Our study found that those who experience two or more head injuries, including even mild head injuries, are at higher risk of subsequent ischemic stroke,” said Dr Holly Elser, lead author of the study and a neurology resident at the Hospital of the University of Pennsylvania, Philadelphia. 

“The findings underscore the importance of public health interventions to reduce the risk of head injury, as well as measures aimed at stroke prevention among individuals with a prior head injury.”

The research team analysed data from the Atherosclerosis Risk in Communities (ARIC) Study of 12,813 adults from diverse communities in the United States, who had not had a head injury or stroke when the study began in 1987. 

After 30 years, 2,158 people had experienced a head injury (73 per cent of which were mild), and of those with a head injury, 147 ultimately had an ischemic stroke.

Those who had a head injury had a 32 per cent increased risk of ischemic stroke, the most common type of stroke. 

Those who had two or more head injuries had a 94 per cent increased risk of ischemic stroke, compared to those with no head injury.

They found the risk of stroke after a head injury was similar among men and women as well as different racial groups.

Ischemic stroke is caused by a blockage in the vessels that supply blood to the brain. 

Prior research has suggested that TBIs might increase the risk of stroke by damaging tiny blood vessels in the brain, the cells lining those blood vessels, and the inner layer of arteries – all of which block or slow blood flow in the brain.

“Our results emphasise the importance of measures that prevent head injury, like always wearing seatbelts in the car and wearing a helmet while biking,” Dr Elser said. 

“Our results also suggest that measures to prevent stroke may be especially important in people who have suffered a head injury, which could include interventions like lowering blood pressure and cholesterol, increasing physical activity and smoking cessation.”