Your Blood Type Can Affect Risk of an Early Stroke, Scientists Discover
Blood types describe the rich variety of chemicals displayed on the surface of our red blood cells.
Among the most familiar are those named A and B, which can be present together as AB, individually as A or B, or not present at all, as O.
Even within these major blood types, there are subtle variations arising from mutations in the genes responsible.
In a study published in 2022, genomics researchers uncovered a clear relationship between the gene for the A1 subgroup and early onset stroke.
Researchers compiled data from 48 genetic studies, which included roughly 17,000 people with a stroke and nearly 600,000 non-stroke controls. All participants were between 18 and 59 years of age.
A genome-wide search revealed two locations strongly associated with an earlier risk of stroke. One coincided with the spot where genes for blood type sit.
A second analysis of specific types of blood-type gene then found people whose genome coded for a variation of the A group had a 16 percent higher chance of a stroke before the age 60, compared with a population of other blood types.
For those with a gene for group O1, the risk was lower by 12 percent.
The researchers noted, however, that the additional risk of stroke in people with type A blood is small, so there is no need for extra vigilance or screening in this group.
"We still don't know why blood type A would confer a higher risk," said senior author and vascular neurologist Steven Kittner from the University of Maryland.
"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."
While the study findings may seem alarming – that blood type could change early stroke risk – let's put these results into context.
Each year in the US just under 800,000 individuals experience a stroke. Most of these events – around three out of every four – occur in people 65 years and older, with risks doubling every decade after the age of 55.
Also, the people included in the study lived in North America, Europe, Japan, Pakistan, and Australia, with people of non-European ancestry only making up 35 percent of participants. Future studies with a more diverse sample could help clarify the significance of the results.
"We clearly need more follow-up studies to clarify the mechanisms of increased stroke risk," Kittner said.
Another key finding of the study came from comparing people who had a stroke before the age of 60 to those that had a stroke after the age of 60.
For this, the researchers used a dataset of about 9,300 people over the age of 60 who had a stroke, and some 25,000 controls over the age of 60 who didn't have a stroke.
They found that the increased risk of stroke in the type A blood group became insignificant in the late-onset stroke group, suggesting that strokes that happen early in life may have a different mechanism compared to those that occur later on.
Strokes in younger people are less likely to be caused by a build-up of fatty deposits in the arteries (a process called atherosclerosis) and more likely to be caused by factors to do with clot formation, the authors said.
The study also found that people with type B blood were around 11 percent more likely to have a stroke compared to non-stroke controls regardless of their age.
Previous studies suggest that the part of the genome that codes for blood type, called the 'ABO locus', is associated with coronary artery calcification, which restricts blood flow, and heart attack.
The genetic sequence for A and B blood types have also been associated with a slightly higher risk of blood clots in veins, called venous thrombosis.
This paper was published in Neurology.
An earlier version of this article was published in September 2022.
Losing Just One Night's Sleep Changes Your Immune System, Study Finds
World First: Scientists Printed Penises For Pigs And Restored Their Erections
Chewing Wood Could Give Your Brain an Unexpected Boost

Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles


Business Wire
10 hours ago
- Business Wire
MaaT Pharma Announces Exclusive Commercialization Partnership With Clinigen for Xervyteg ® in acute Graft-versus Host Disease in Europe
LYON, France--(BUSINESS WIRE)--Regulatory News: Clinigen's hemato-oncology expertise and leading European position in hospital distribution and market access make this team the ideal fit to bring this therapy to patients. MaaT Pharma (EURONEXT: MAAT – the 'Company'), a clinical-stage biotechnology company and a leader in the development of Microbiome Ecosystem Therapies TM (MET) dedicated to enhancing survival for patients with cancer through immune modulation, today announces the signature of a license and commercial agreement with Clinigen, a global specialty pharmaceutical services group and a leading European player in hospital distribution and market access, to streamline the pathway for ensuring access to this medicine across Europe 1. With this partnership, MaaT Pharma demonstrates its capability to supply products to pharmaceutical companies, including those specializing in rare diseases while ensuring scale-ups for commercial and extending its cash runway into January 2026. Hervé Affagard, CEO and co-founder of MaaT Pharma says: 'This deal is a pivotal step in bridging MaaT Pharma's innovation with healthcare professionals who care for patients with aGvHD. Clinigen's hemato-oncology expertise and leading European position in hospital distribution and market access make this team the ideal fit to bring this therapy to patients and we're confident that this new relationship will maximize the full revenue generation potential of full revenue generation potential of Xervyteg ® (MaaT013). I look forward to working closely with the Clinigen team as we prepare for a successful launch.' Jerome Charton, CEO of Clinigen, says: ' Following the EMA's acceptance of MaaT Pharma's submission of an application for assessment for MaaT013 in June, we are very excited about this new relationship. This collaboration brings a novel technology to the forefront of rare disease and oncology care. We're proud to play a leading role in ensuring access across Europe to this innovative therapy, and we look forward to working closely with MaaT Pharma as we prepare for potential launch.' Transaction Terms Under the terms of the agreement, MaaT Pharma will grant Clinigen exclusive European rights to distribute this medicine for the treatment of patients with aGvHD, if approved by the EMA. MaaT Pharma will receive an upfront payment of €10.5 million and additional eligible payments of up to €18 million depending on the achievement of pre-specified regulatory and sales milestones. MaaT Pharma will also be eligible to receive royalty payments on net sales of a percentage in the mid-thirties and regular cash flow as per the supply agreement. The hematology community has expressed interest in this medicine and this class of medicines to treat patients with aGvHD, as evidenced by the growing requests of Early Access Program between 2023 and 2024 (+75%). This program has been active in Europe since 2019. Under the terms of the agreement, Clinigen will take over this activity to meet the growing expectations of physicians while allowing MaaT Pharma to optimize its internal resources. This transition enhances MaaT Pharma's capacity to focus on clinical development, regulatory milestones, and industrial scale-up. MaaT Pharma management will host a conference call and webcast tomorrow Thursday, July 3 nd, 2025, at 3:00pm CET/ 9:00am EDT/ 6:00am PT/ 9:00pm CST. To register, please click here. Participants can also attend the conference by phone by dialing the following number: +33 1 78 42 94 76 + and using the PIN code 43 92 58 1 Includes the following countries: European Union, Iceland, Norway, Liechtenstein and the United Kingdom About Clinigen Clinigen is a global, specialist pharmaceutical services company focused on providing ethical access to medicines. Its mission is to accelerate access to medicines for patients in every corner of the globe. The Group supports pharmaceutical and biotech companies across the medical product lifecycle, from clinical through to commercial and operates from sites in North America, Europe, Africa, and the Asia Pacific. Clinigen has more than 1,100 employees across five continents in 15 countries and provides access in more than 130 countries every year. For more information on Clinigen, please visit About MaaT Pharma MaaT Pharma is a leading, late-stage clinical company focused on developing innovative gut microbiome-driven therapies to modulate the immune system and enhance cancer patient survival. Supported by a talented team committed to making a difference for patients worldwide, the Company was founded in 2014 and is based in Lyon, France. As a pioneer, MaaT Pharma is leading the way in bringing the first microbiome-driven immunomodulator in oncology. Using its proprietary pooling and co-cultivation technologies, MaaT Pharma develops high diversity, standardized drug candidates, aiming at extending life of cancer patients. MaaT Pharma has been listed on Euronext Paris (ticker: MAAT) since 2021. Forward-looking Statements All statements other than statements of historical fact included in this press release about future events are subject to (i) change without notice and (ii) factors beyond the Company's control. These statements may include, without limitation, any statements preceded by, followed by, or including words such as 'target,' 'believe,' 'expect,' 'aim', 'intend,' 'may,' 'anticipate,' 'estimate,' 'plan,' 'project,' 'will,' 'can have,' 'likely,' 'should,' 'would,' 'could' and other words and terms of similar meaning or the negative thereof. Forward-looking statements are subject to inherent risks and uncertainties beyond the Company's control that could cause the Company's actual results or performance to be materially different from the expected results or performance expressed or implied by such forward-looking statements. About acute Graft-versus-Host Disease Acute Graft-versus-Host Disease occurs in patients within 100 days of undergoing a stem cell or bone marrow transplant, where the transplanted cells initiate an immune response and attack the transplant recipient's organs, causing inflammation of the skin, liver and/or gastro-intestinal tract and leading to significant morbidity and mortality. GI involvement is associated with severe complications such as profound diarrhea, abdominal pain, intestinal bleeding, and death. These complications are often life-threatening, with increased mortality risk, due to the challenges of managing severe GI inflammation and the associated risks of infection, malnutrition, and organ failure. The standard first line therapy for treating aGvHD is the use of systemic steroids. If patients do not respond to steroids, they are considered Steroid Resistant (SR) and other agents can be administered. Currently the only agent approved for treating SR aGvHD after failure of steroid treatment is ruxolitinib, which is currently approved for this indication in USA and has received approval from the European Medicines Agency's Committee for Human Medicinal Products (CHMP) on March 25, 2022. About MaaT013 (Xervteg®) MaaT Pharma's Microbiome Ecosystem Therapies (MET) are designed to leverage a full microbiome ecosystem to restore balance and maximize clinical benefits for patients with severe, treatment-induced dysbiosis in acute diseases. MaaT013 (Xervyteg ®) is a full-ecosystem, off-the-shelf, standardized, pooled-donors, enema Microbiome Ecosystem Therapy TM for acute, hospital use. It is characterized by a consistently high diversity and richness of microbial species and the presence of Butycore TM (a group of bacterial species known to produce anti-inflammatory metabolites). MaaT013 (Xervyteg ®) aims to restore the symbiotic relationship between the patient's functional gut microbiome and their immune system to correct the responsiveness and tolerance of immune functions and thus reduce steroid-resistant, gastrointestinal (GI)-aGvHD. MaaT013 (Xervyteg ®) has been granted Orphan Drug Designation by the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA).


Newsweek
11 hours ago
- Newsweek
Video Shows Snake Trying To Eat Prey 10 Times Her Size
Based on facts, either observed and verified firsthand by the reporter, or reported and verified from knowledgeable sources. Newsweek AI is in beta. Translations may contain inaccuracies—please refer to the original content. A snake in Denmark has been spotted attempting to consume an oversized hare that's 10 times larger than itself. The chance observation of an adult female common European adder killing and intending to swallow a much larger prey—a European young hare—was captured in a series of videos by Klaus Birch, the co-author of a study on the encounter published in the journal Herpetozoa. The moment unfolded on the island of Læsø in the Kattegat region of northern Denmark—near a dirt road in open grassland around 32 feet from a sandy beach—back in August 2022. The snake appeared to be in a low nutritional status, likely after having given birth recently, the study said. "The adder under these circumstances might have benefited from a large prey to gain maximum energy after likely having given birth," the researchers said. Stills from videos showing a female Vipera berus snake biting and pulling the hare's front leg (pictured left) and examining and biting the head (pictured right). Stills from videos showing a female Vipera berus snake biting and pulling the hare's front leg (pictured left) and examining and biting the head (pictured right). Klaus Birch Birch arrived at the scene and found the adder examining the young hare and biting its left hind leg. "The hare was lying on the ground moving its four legs jerkily and head with difficulty and was unable to stand up," the researchers wrote in the study. The adder was startled by Birch's presence and escaped into the grass nearby. Within seconds, the adder returned to the hare and continued examining it, especially the front legs and the head, before zipping away into the grass again. However, around 20 seconds later, the snake returned to the scene and examined the hare "carefully and energetically," starting with its posterior parts, biting and moving the right hind leg, the study notes. The snake then examined the anterior parts of the hare, biting and pulling a front leg, before also biting its head. "The hare was still breathing but moved less than before," the study said. Birch chased the snake away and took the hare to attempt to save its life, but it died after around 30 minutes. While it is unknown whether the adder would have tried to swallow the hare had Birch not intervened, the researchers believe it is "likely" that the snake "would have abandoned its excessively large prey after careful examination." The study noted that it is unusual for snakes to regularly attack vastly oversized prey items that are clearly impossible to swallow. However, cases like this have been reported in previous research, such as an earlier observation of snakes that overestimated their abilities to swallow young rabbits and died while trying to do so. A previous study also noted a case of a snake that was found dead after it had just swallowed a large field vole. "The mass of the prey was 26g and the snake's mass after the prey had been removed was 28g. The adder had therefore consumed a meal equivalent to 92.9 percent of its mass," the team noted. The researchers concluded: "The above cases indicate that snakes killing and subsequently abandoning oversized prey items may well be an underreported phenomenon." Do you have a tip on a science story that Newsweek should be covering? Do you have a question about snakes? Let us know via science@ Reference Bringsøe, H., Jablonski, D., & Birch, K. (2025). Overly optimistic adder, Vipera berus (Linnaeus, 1758), killing and intending to swallow an oversized young hare, Lepus europaeus Pallas, 1778. Herpetozoa, 38, 155–159. Bull, D. (2016). Vipera berus (northern viper): Morphometrics of feeding on a common field vole. Herpetological Bulletin, 136, 33–34.


Miami Herald
13 hours ago
- Miami Herald
Overnight Canaveral launch marked 500th for SpaceX Falcon 9
An early Wednesday morning launch on the Space Coast marked the 500th time SpaceX has flown its workhorse Falcon 9 rocket, reusing the fleet-leading first stage booster for a record 29th time. The latest flight with a payload of 27 Starlink satellites lifted off Cape Canaveral Space Force Station's Space Launch Complex 40 at 2:28 a.m. coming just over nine hours since launch No. 499 from neighboring Kennedy Space Center, which sent up a European weather satellite. The booster, which first flew in 2021 and had since been used on two human spaceflights among 28 previous missions, completed flight 29 landing downrange on the droneship A Shortfall of Gravitas. The first Falcon 9 launched in 2010, and only two of the 500 launches have ended in complete failure. Elon Musk's company had its first successful orbital launch with the Falcon 1 rocket in 2008, but it only flew one more time before switching to the Falcon 9. It also has flown the Falcon Heavy, which is essentially three Falcon 9 rockets strapped together, 11 times. The launch was the 83rd Falcon 9 mission for SpaceX in 2025 from all of its facilities in Florida and California. No Falcon Heavy has launched yet this year. For the Space Coast, it marked the 58th orbital mission, with all by three flown by SpaceX. ------------ Copyright (C) 2025, Tribune Content Agency, LLC. Portions copyrighted by the respective providers.