DID YOU KNOW THOSE WITH ONE PARTICULAR BLOOD TYPE are associated with a slightly higher risk for early onset stroke? That’s the finding of a recent meta-analysis of nearly 17,000 individuals who suffered from a stroke before age 60. Today we look at blood type and stroke risk
What is the higher-risk blood type? Those with type A have a slightly higher risk, while individuals with type O blood have a slightly lower risk of early onset stroke.
Stroke basics
A stroke is a medical emergency. There are two types of stroke, ischemic and hemorrhagic. Ischemic stroke is more common and happens when a blood clot blocks a blood vessel in the brain. When the blood vessel is obstructed, blood cannot flow to the brain. Within minutes, brain cells begin to die.
Sometimes an artery narrowing (stenosis) can be the cause of a stroke. Stenosis can occur with atherosclerosis, a plaque build-up in the artery.
Hemorrhagic stroke is caused by bleeding into the brain because of the rupture of a blood vessel. Unfortunately, hemorrhagic stroke is associated with severe morbidity and high death rates. Progression of hemorrhagic stroke is associated with worse outcomes.
Early diagnosis and management are critical, given the usual rapid expansion of bleeding, resulting in neurological dysfunction and the sudden deterioration of consciousness.
Transient ischemic attacks (TIAs) happen when the brain’s blood supply is briefly interrupted. A TIA can put you at risk of a more serious stroke. TIAs are emergencies.
Stroke symptoms include:
- Sudden weakness or numbness of the face, arm, or leg (especially on one side of the body)
- Sudden difficulty speaking, understanding speech, or confusion
- Sudden challenges seeing in one or both eyes
- Sudden dizziness, loss of balance, trouble walking, or coordination
- Sudden severe headache (with no known cause)
Stroke is an emergency: Please remember that it is critical to seek medical care immediately if you are someone for whom you care has any symptoms suggestive of a stroke.
Stroke history
The Battle of Halule in 691 BC marked a critical period in the Ancient Near East. It showed the complex power balance between the Ancient Assyrian Empire and a group of kingdoms that eventually became the Persian Empire.
While the Assyrians (led by the biblical figure Sennacherib) lost the battle, they re-invaded Babylon two years later. The Assyrians great took advantage of the suffering of the opposing king, Elamite Humban-Nimena III (ruler from 692 BC to 689 BC). The king had “ his mouth seized so that he could not speak.” The king died from a stroke. The stroke even had tremendous geopolitical ramifications.
In 1658, in his Apoplexia, Johann Jacob Wepfer (1620–1695) identified the cause of hemorrhagic stroke. The Swiss pathologist and pharmacologist suggested that individuals who died of “apoplexy” had brain bleeding.
Blood type and early-onset stroke risk
Ischemic stroke is a complex genetic disorder that is the product of environmental and genetic factors.
We know that there is a genetic predisposition to stroke, and researchers are trying to identify genes associated with stroke. In the Framingham Study, parental history of ischemic stroke before age 65 appeared to be associated with a 2.2-fold increase in the risk of ischemic stroke in offspring.
Numerous genome-wide association studies (GWAS) of stroke have aimed to understand the role of inherited genetics better. Today, we look at a new GWAS evaluation looking at blood type and the risk of early-onset stroke.
The Genetics of Early Onset Ischemic Stroke Consortium, a collaboration of 48 studies across North America, Europe, Japan, Pakistan, and Australia, recently assessed early-onset ischemic stroke in patients 18 to 59.
Let’s get right to the findings:
People with type A blood have just over a one-sixth (16 percent) higher risk for early onset stroke than those with other blood types.
A separate meta-analysis of nearly 17,000 cases of ischemic stroke in adults younger than 60 years showed that having type O blood reduced the early-onset stroke risk by about one-eighth (12 percent).
Moreover, the genetic associations of stroke risk were much stronger in early-onset stroke than those with late-onset stroke. This suggests a stronger role for clot risk-raising factors in the younger cohort.
Blood type and early onset stroke risk — My take
Ischemic stroke risk increases exponentially with age. Still, about 1 in 10,000 individuals in the 15 to 45-year age range will suffer from a stroke, at least among those of predominantly European ancestry. For Blacks, the risk is double that amount.
The risk factors for early-onset stroke are similar to those for late-onset disease, but the incidence of these risk facts (and their effects on stroke) differ by age.
Compared with older adults, individuals 18 to 44 with ischemic stroke have a lower prevalence of diabetes, high blood pressure, cholesterol problems (dyslipidemia), and atrial fibrillation. The younger cohort is also less likely to have a history of coronary or peripheral artery disease.
On the other hand, despite their lower prevalence, some stroke risk factors appear to have a stronger effect on the young population. The relative risk of stroke associated with high blood pressure is four-fold higher among those under 50 (and decreases with age).
Reducing stroke risk — 7 tips
Harvard Health Publishing offers that while you can’t reverse the years or change your family history, there are many other stroke risk factors that you can control.
- Lower blood pressure
- Lose weight
- Exercise more. For example, take a walk around your neighborhood every morning after breakfast.
- If you drink alcohol, do so in moderation.
- Treat atrial fibrillation
- Treat diabetes
- Avoid smoking, as it accelerates clot formation.
Thank you for joining me today in this look at blood type and early-onset stroke risk.
The information I provided in this blog is for educational purposes only and does not substitute for professional medical advice. Please consult a medical professional or healthcare provider if you seek medical advice, diagnoses, or treatment. I am not liable for risks or issues associated with using or acting upon the information in this blog.
