Which Blood Type Increases Your Risk of Dementia?

Esther Heerema, MSW
·2 min read

Medically reviewed by Brigid Dwyer, MD

Science has identified several risk factors for dementia including smoking, high blood pressure, genetics, diabetes and more. But one study suggests that your blood type may also influence your risk for cognitive problems, affecting memory, word-finding, personality, and more.

Lutz Pape / Getty Images
Lutz Pape / Getty Images

Risk Factors

A team of researchers studied more than 30,000 people over the course of a 3 1/2 year period. During the study, the participants' cognitive functioning was tested to determine if any decline was present. Researchers used tests that measured verbal fluency, immediate memory, orientation, and ability to learn a 10-word list.

At the end of the study period, significant cognitive decline had developed in 495 people. Of this group, researchers found that one particular blood type demonstrated a higher risk for cognitive decline. Blood type AB was associated with an increased risk of cognitive impairment with an odds ratio (OR) of 1.82 (95% CI 1.15–2.90). This was independent of age, race, region, and sex. Additionally, higher levels of factor VIII- a protein that facilitates clotting of blood- were also correlated with a greater risk of cognitive problems, with an OR of 1.24 (95% CI 1.10–1.38 per each 40 IU/dL higher FVIII).



What Is an Odds Ratio?

An odds ratio (OR) is a measure of association between risk factors (or exposures) and outcomes. In other words, the "odds" is the ratio of the probability that the event of interest (or outcome) occurs to the probability that it does not occur. Therefore, an odds ratio greater than 1 suggests that the outcome is more likely in the exposed group versus the non-exposed group.



How Many People Have the AB Blood Type?

AB blood is quite rare. According to the American Red Cross, about 4% of Caucasians, 4% of African-Americans, 2% of Latino Americans and 7% of Asian Americans have AB blood.

Why Is the Risk Higher?

One theorized reason by the study's authors why blood type AB is correlated with a higher risk of cognitive impairment is that this blood type influences cardiovascular disease (CVD) risk, and research has already demonstrated a tie between CVD risk factors and cognitive decline.

What Should You Do if You Have AB Blood?

First, remember that this is only a single study, and it needs to be replicated to determine if the same results occur in other research.

Also, although this study does show a correlation (note that it does not prove that one causes the other) between blood type and risk of cognitive decline, research has demonstrated that there are many other factors that have shown to be associated with a reduced risk of dementia. In other words, there are many things that you CAN control that reduce your dementia risk. Diet, physical exercise, and mental activity all have repeatedly been correlated with reduced risk of dementia.

Read the original article on Verywell Health.