According to a recent research, there may be a link between rare blood type AB and memory loss in later life.
People with AB blood, found in 4% of the population, appear more likely to develop thinking and memory problems than those with other blood groups.
The study, published in Neurology, builds on previous research showing blood type may influence heart risk.
A charity said the best way to keep the brain healthy was a balanced diet, regular exercise and not smoking.
The research team led by Dr. Mary Cushman, of the University of Vermont College of Medicine, Burlington, analyzed data from about 30,000 US citizens aged 45 and above.
It identified 495 participants who had developed thinking and memory problems, or cognitive impairment, during the three-year study.
They were compared to 587 people with no cognitive problems.
People with AB blood type made up 6% of the group who developed cognitive impairment, which is higher than the 4% found in the general population.
The study supported the idea that having a certain blood group, such as O, may give a lower risk for cardiovascular disease, which in turn protected the brain, the researchers said.
“Our study looks at blood type and risk of cognitive impairment, but several studies have shown that factors such as high blood pressure, high cholesterol and diabetes increase the risk of cognitive impairment and dementia,” said Dr. Mary Cushman.
“Blood type is also related to other vascular conditions like stroke, so the findings highlight the connections between vascular issues and brain health. More research is needed to confirm these results.”