Losing your memory as you get older might seem like a sad inevitability, but dementia doesn't affect everyone. In fact, many people make it through older age without ever experiencing the loss of their memory and other cognitive functions. So what causes dementia? Because there are so many different variations of the condition and potential risk factors, it's hard to pinpoint one source. However, it turns out that one of your innate characteristics might play a role: One study found that your blood type could raise your risk of developing dementia. Read on to find out which blood type is associated with a higher risk, and for more things your blood type can tell you, If You Have This Blood Type, Your Heart Attack Risk Is Higher, Study Says.
If you have blood type AB, you're more likely to develop dementia.
A 2014 study published in Neurology, the medical journal of the American Academy of Neurology, found a connection between blood type and dementia. Researchers for the study—which was part of a larger study of more than 30,000 people observed for more than three years—identified 495 participants who developed thinking and memory problems during the study, and compared them to 587 people who experienced no cognitive impairment. They found that people with blood type AB were 82 percent more likely to develop thinking and memory problems that can lead to dementia than those with other blood types. And for more risk factors to be aware of, Sleeping Less Than This Many Hours Per Night Doubles Your Dementia Risk.
This could be the result of a protein that people with AB blood are more likely to have.
Researchers for the study also looked at the blood levels of factor VIII, which is a protein that helps the blood to clot. According to the study, people who had high levels of factor VIII protein were also at a higher risk of dementia, as they were 24 percent more likely to develop thinking and memory problems than people with lower levels of this protein. In an article for The Conversation, study co-author Kristine Alexander, PhD, a medical policy research analyst for Cambia Health Solutions, wrote that people with blood type AB have the highest levels of factor VIII—nearly 40 percent higher than those with blood type O. And for more useful health content delivered straight to your inbox, sign up for our daily newsletter.
People with AB blood also have a higher risk of stroke, which can lead to dementia.
A different 2014 study done by the same group of researchers—and part of the same larger study—found that when compared with blood type O, blood type AB was associated with an increased risk of stroke, while blood type A and B were not. According to WebMD, people who have had a stroke are far more likely to develop dementia than people who have not. In fact, about one in four people who have had a stroke will go on to develop signs of dementia.
"Blood type is also related to other vascular conditions like stroke, so the findings highlight the connections between vascular issues and brain health," Mary Cushman, MD, an author for both studies and a hematologist at the University of Vermont Medical Center, said in a statement. And for more on stroke risks, check out these 17 Surprising Habits That Increase Your Risk of a Stroke.
Blood type AB is the least common blood type, however.
Fortunately, if you don't know your blood type, there's a very good chance that you do not have blood type AB. According to the American Red Cross, blood type AB is the least common blood type in the U.S. Less than 1 percent of Americans have AB negative blood, while less than 4 percent have AB positive blood. In comparison, about 43 percent of Americans have type O blood.
"With that in mind, there is no reason to panic if you have blood type AB. There are a number of lifestyle factors that can reduce your risk of cognitive problems and dementia, and many of them have more of an impact than your blood type," Alexander wrote for The Conversation. She cited eating well and getting exercise as two healthy lifestyle choices that "are important for both cardiovascular and brain health." Furthermore, Alexander added that "keeping blood pressure, cholesterol, and blood sugar under control will also lower your risk for these problems." And for more risks associated with blood types, If You Have Type A Blood, You’re at Higher Risk for This Kind of Cancer.