Blood sample
Results showed a direct link between AB blood group and cognitive decline.littlepomegranate/Flickr

A person's blood type can tell whether he or she will develop dementia later in life, researchers reveal.

In a large study conducted on 30,000 Americans, people with AB blood group had 82% higher risk of experiencing memory loss and dementia than people who had other blood groups.

Researchers conducted different cognitive tests to find out the prevalence of "incident cognitive impairment" in the participants. Nearly 495 participants had thinking and memory problems. About 6% of the group had AB blood type.

To confirm the link between AB blood group and dementia, researchers selected another 587 people without any memory issues.

Results showed a direct link between AB blood group and cognitive decline.

To be cited as another remarkable finding of the study, researchers noticed that factor VIII (FVIII), an important protein needed for blood clotting, also played a huge role in cognitive decline.

People with higher levels of FVIII had a 24% increased risk of memory and thinking problems than those with lower levels. Level of FVIII was higher in AB type blood group than others.

However, researchers urged the public not to get panic with the findings as the risk was relatively very small. "People who have AB blood type should not be overly worried about these findings since the association we saw was relatively small and requires other research for confirmation," author of the study Mary Cushman of the University of Vermont College of Medicine in Burlington, told Health Day.

The study has been published in Neurology.

The blood group of a person is decided by antigens and antibodies present in the blood. Following are the four different blood groups, provided by NHS Choices UK:

  • People with blood group A have A antigens on red blood cells and anti-B antibodies in plasma
  • People with blood group B have B antigens and anti-A antibodies in the red blood cells and in plasma respectively
  • People with AB blood group have A and B antigens. They don't have any antibodies in plasma
  • Those with blood group O have anti-A and anti-B antibodies, but do not have any antigens

Previous studies have shown that blood group of a person influenced his or her health. In a study conducted on 20,000 people, researchers from the Pennsylvania University found that people with blood group O had a lowered risk of heart attacks.

Another study published in the Journal of the National Cancer Institute found an increased risk of pancreatic cancer in people who had type B (72%), type AB (51%) and type A (32%) blood group.

Research has also linked blood group AB or B in women to ovarian cancer; O blood type in men to obesity; blood group A to gastric cancer, blood group O to peptic ulcers, lowered egg count and poorer egg quality in women, according to Body and