Looking at nearly 50 studies previously published on the relationship between genes and ischemic stroke, researchers have found blood type may play a role in the likelihood of young adults experiencing this life-threatening event.
“The number of people with early strokes is rising,” explained Steven Kittner, from the University of Maryland Medical Center and co-lead on the new research. “These people are more likely to die from the life-threatening event, and survivors potentially face decades with disability. Despite this, there is little research on the causes of early strokes.”
Building on several years of research into the relationship between blood type and clotting, Kittner and colleagues performed a meta-analysis rolling together data from 48 different studies. The focus was on the genetic differences between around 17,000 stroke patients and 600,000 healthy controls, all aged between 18 and 59.
The research homed in on a particular gene variant that seemed to correlate with a higher risk of early-onset stroke. That gene determined a person’s blood type.
The findings revealed people with type A blood were 16% more likely to experience a stroke before the age of 60 compared to those with other blood types. Blood type O people were least likely to experience an early stroke, around 12 percent less likely compared to all other blood types. After the age of 60 there was no difference in stroke risk detected between different blood types.
“This study raises an important question that requires a deeper investigation into how our genetically predetermined blood type may play a role in early stroke risk,” said Mark Gladwin, from the University of Maryland School of Medicine.
So what could be going on here?
The researchers do suggest there is prior evidence to indicate blood clotting differences between blood types. Those with type A blood have been found to be at a greater risk of suffering clotting conditions such as deep vein thrombosis, while those with type O blood tend to be more likely to experience serious bleeding events.
“We still don’t know why blood type A would confer a higher risk, but it likely has something to do with blood-clotting factors like platelets and cells that line the blood vessels as well as other circulating proteins, all of which play a role in the development of blood clots,” noted Kittner. “We clearly need more follow-up studies to clarify the mechanisms of increased stroke risk.”
The new study was published in the journal Neurology.
