AB blood type may increase dementia risk

People with the least common blood type, AB, are more likely to develop thinking and memory problems that can lead to dementia in later years than people with other blood types, says a study.

"Our study looks at blood type and risk of cognitive impairment," said study author Mary Cushman from the University of Vermont, College of Medicine in Burlington.

Those with AB blood were 82 percent more likely to develop memory problems than others.

"Blood type is also related to other vascular conditions like stroke, so the findings highlight the connections between vascular issues and brain health," Cushman added.

The study was part of a larger study (Reasons for Geographic And Racial Differences in Stroke) of more than 30,000 people followed for an average of 3.4 years.

People with AB blood type made up 6 percent of the group who developed cognitive impairment, which is higher than the 4 percent found in the population.

The researchers also looked at levels of factor VIII, a protein that helps blood to clot. High levels of factor VIII are related to higher risk of cognitive impairment and dementia.

People with AB blood had a higher average level of factor VIII than people with other blood types.

The study appeared in the journal Neurology.