People with type A blood may be at greater risk of having a stroke before the age of 60 in comparison with different blood teams, researchers have discovered.
In distinction, these with blood type O are much less prone to have an early-onset stroke, in keeping with the brand new meta-analysis.
The analysis was carried out by a workforce led by scientists from the University of Maryland School of Medicine within the United States, who regarded on the relationship between genetic traits resembling blood type and their relationship to stroke.
To accomplish that, they checked out information from 48 genetic research on ischemic strokes in adults between the ages of 18 and 59. Ischemic strokes are brought on by a blockage of blood movement to the mind.
In complete, the research included round 17,000 stroke sufferers and practically 600,000 wholesome controls who had by no means skilled a stroke.
“We were interested in trying to identify the genetic determinants of stroke,” the study’s co-principal investigator Braxton Mitchell told Euronews Next.
“For stroke, we have recognized for a very long time that there is a massive environmental element, however there’s additionally a genetic element,” said Mitchell, who is a professor of medicine at the University of Maryland School of Medicine.
To examine this further, he and his colleagues looked across people’s genetic profiles, and ended up finding a link between early-onset stroke and the area of the chromosome that includes the gene determining a person’s blood type.
Humans have four main blood groups, A, B, AB and O, and a person’s blood group is determined by the genes they inherit from their parents. Blood group O is the most common.
What the researchers found was that those who had early-onset stroke were more likely to have blood type A and less likely to have blood type O, compared to people with late stroke and people who had never had a stroke.
“Having blood type A will increase your risk by about 16 per cent for early-onset stroke, however solely about 5 per cent for later onset stroke,” said Mitchell.
“If you have got blood type O, you are 12 per cent much less prone to get early-onset stroke, in comparison with solely 4 per cent much less prone to get later onset stroke”.
Increased risk of stroke very modest
But although the researchers found associations between having blood type A and the risk of early-onset stroke, they emphasised that the increased risk was very modest.
They stress that those with type A blood should not worry about having an early-onset stroke, or engage in extra screening or medical testing based on this finding.
“Clinically, we should not be anxious about our blood varieties placing us at excessive risk for stroke,” said Mitchell.
“There are different risk elements for stroke which might be rather more necessary, like hypertension and smoking, for instance. So if we wish to cut back our risk of stroke, these are actually the elements that we must be taking note of”.
He added: “Having mentioned that, what we marvel about is whether or not when you’ve got these risk elements, and also you even have blood type A, does that make these risk elements much more highly effective? We do not know that but. But that is one of the issues that we’re “.
It’s still unclear as to why blood type A confers this higher risk, but researchers think it might have something to do with blood clotting factors.
Other studies have suggested that those with an A blood type have a slightly higher risk of developing blood clots in the legs – known as deep vein thrombosis.
“This type of pro-clotting background of having blood group A in all probability places you at greater risk for clotting-related ailments, of which stroke is one of them,” said Mitchell.
One limitation of the analysis was the relative lack of diversity among participants, the majority of whom were of European ancestry, with researchers welcoming further follow-up studies on a more diverse population.
“We all have totally different genetic variants, and genetic variants typically are inclined to cluster inside totally different ancestry teams,” said Mitchell.
“So we may be lacking some necessary variants by solely a small illustration of ancestry teams”.
Blood type linked to risk of other conditions
It’s not just stroke risk – other research has suggested links between blood type and the risk of developing other health conditions.
For example, a study by scientists from the Harvard School of Public Health found that people with blood types A, B, or AB have a higher risk for coronary heart disease than people with blood type O.
Those with the rarest blood type, AB, had the greatest risk.
Other studies have suggested people with type A blood have a higher risk of stomach cancer, compared to those with other blood types.
It’s worth keeping in mind though that although studies have shown a relationship between blood type and certain health conditions, we still really don’t know the causes of these relationships.
So if you have type A blood, how worried should you be?
A person can’t really change their blood type, Mitchell points out. And there are other risk factors for stroke that are more within a person’s control, like nicotine habits, blood pressure, alcohol use and amount of exercise.
“I’d say, do not be anxious in any respect,” mentioned Mitchell. “I’d take into consideration these different modifiable risk elements and give attention to these, as a result of they don’t seem to be solely risk elements for stroke, however these are risk elements for coronary heart illness and cancers, and so forth”.
‘Great step’ towards helping to reduce stroke risk
Commenting on the findings, Clare Jonas from UK charity Stroke Association said the results were a “nice step” towards better monitoring of risk factors for early stroke.
“The majority of strokes occur to older folks, attributable to causes we’re generally conscious of resembling excessive blood stress, thickening of the arteries, or atrial fibrillation,” said Jonas, who is Research Communications and Engagement Lead at the Stroke Association, which provides support to those who have suffered a stroke.
“The causes of stroke in youthful adults aren’t as nicely understood, which makes them tougher to forestall,” she said in a statement.
“We don’t but know why folks with blood type A is perhaps at elevated risk of early stroke. This means we are able to’t but develop focused preventions for early stroke”.
“However, this analysis is a nice step in the direction of serving to healthcare professionals work out who would most profit from monitoring for different risk elements and being supplied interventions to assist cut back risk,” she added.