Scientists have long sought for a treatment that could cure Alzheimer's disease, an age-related neurodegenerative disease characterized by memory loss as well as behavioral and thinking problems. Preventive measures to reduce one's risks for the disease are not conclusive.

Researchers from the University of Sheffield in Britain, however, have found one factor that reduces a person's risks of suffering from the illness, the most prevalent form of dementia and which scientists remain stumped on its causes.

In a new study published in the Brain Research Bulletin, researchers looked at the results of 189 MRI scans from healthy individuals. They calculated the volumes of the grey matter in the brain and looked at the differences depending on the volunteers' blood type.

Grey matter is largely made up of neuronal cell bodies and is involved in the processing of information in the brain. It is known to reduce risks for diseases such as Alzheimer's.

The researchers found that those with an O blood type tend to have more grey matter in their brain compared with those with A, B or AB blood types, who notably had less grey matter in the areas of the brain involved in the formation of long-term memories.

The researchers said that a reduction in the volumes of grey matter is typically seen in people's brain as they age and this difference will intensify among those with different blood types as a result of ageing.

"The findings seem to indicate that people who have an 'O' blood type are more protected against the diseases in which volumetric reduction is seen in temporal and mediotemporal regions of the brain like with Alzheimer's disease for instance," said study researcher Matteo De Marco, from the University's Department of Neuroscience.

The findings of the study mirrored another study on blood type and brain function. The 2014 research conducted by researchers from the University of Vermont found evidence that people with AB blood type have increased risks of suffering from cognitive problems as they get older.

Nonetheless, the researchers of the new study acknowledged that additional research are needed to determine other biological mechanisms that could contribute to risks of Alzheimer's.

The researchers said that the biology of blood types appear to influence the development of the nervous system but experts said that for those who do not have O blood type, some studies suggest that adopting a healthy diet and engaging in mediation may help grow grey matter.

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