The Blood Types That Can Increase Your Risk Of Dementia

Unless you donate blood often, you probably don't know your blood type. Blood types are distinguished by the types of proteins, called antigens, found on your red blood cells. A person with an A blood type has the A antigen on the blood cells and the B antibody in the plasma. Whether you have a positive or negative blood type (like A+) depends on whether you have an inherited protein on your blood cells.

Your blood type might not factor too much into your life unless you need a blood or plasma transfusion. However, your blood type can show your propensity to certain conditions. A 2014 study in Neurology found that people with the less common AB blood type had an 82% higher risk of developing memory and thinking problems compared to people with type O.

"Blood type is also related to other vascular conditions like stroke, so the findings highlight the connections between vascular issues and brain health," said study author Mary Cushman, M.D. in a news release. The study also found that people with the AB blood type had a higher average level of a certain clotting protein called Factor VIII, which is linked to cognitive decline and dementia.

A small percentage of people in the United States have the AB blood type, whereas the O blood type is much more common. If you're one of those people with the AB blood type, it doesn't necessarily mean you're going to develop dementia. In fact, other studies have found different results, suggesting that blood type may not always have a strong link to cognitive decline. A 2017 study in Medical Science Monitor found that older adults with the A blood type were more likely to experience postoperative cognitive dysfunction. However, a 2015 study in PLoS One involving 1.5 million people determined that blood type had no link to dementia. Those over 70 with the A blood type had a 7% lower risk of developing dementia compared with those with blood type O. (Read other ways your blood type can affect your health.)

Compared with the O blood type, people with the A, B, and AB blood types have higher levels of proteins that affect clotting, according to a 2022 meta-analysis in Neurology. The ABO gene, which determines your blood type, is also linked to other proteins that affect inflammation and blood vessel function. Inflammation of the brain is associated with cognitive decline (per a 2022 article in the International Journal of Molecular Sciences), and vascular dementia results from reduced blood flow to the brain.

Although you can't change your blood type, you can lower your risk of cognitive decline through several lifestyle changes. The World Health Organization recommends exercise because it not only protects the brain but also reduces inflammation and boosts your immune system. You should aim for at least 150 minutes each week of moderate aerobic activity or 75 minutes of vigorous aerobic exercise. It's fine to split up your exercise into 10-minute bouts. Adults over 65 should also strength train at least twice a week and work on their mobility three times a week to prevent falls.

Your diet can also play a role in your risk of dementia. Adopting a healthy eating plan such as the Mediterranean Diet or the MIND Diet can support your cognition now and later in life. A 2017 review in Alzheimer's and Dementia found that obesity in midlife is associated with a 33% increased risk of dementia, so following a healthy diet and exercise program can help reduce excess weight. You'll also want to curb your excessive drinking habits. Because smoking at midlife is linked to dementia later in life, the WHO suggests enrolling in a smoking cessation program. Managing your high blood pressure, diabetes, high cholesterol, and depression is also important to reduce your dementia risk.