Blood Type and Cognitive Decline

It is probably a good idea to be skeptical of links claimed between blood type and measures of degenerative aging. The evidence to date is either nebulous or shows little to no correlation. Where correlations are found the effects are not large, or are not reproduced in other study populations. Nonetheless, here is another paper on this topic:

Researchers claim that people with an 'O' blood type have more grey matter in their brain, which helps to protect against diseases such as Alzheimer's, than those with 'A', 'B' or 'AB' blood types. The researchers made the discovery after analysing the results of 189 Magnetic Resonance Imaging (MRI) scans from healthy volunteers. The researchers calculated the volumes of grey matter within the brain and explored the differences between different blood types. The show that individuals with an 'O' blood type have more grey matter in the posterior proportion of the cerebellum. In comparison, those with 'A', 'B' or 'AB' blood types had smaller grey matter volumes in temporal and limbic regions of the brain, including the left hippocampus, which is one of the earliest part of the brain damaged by Alzheimer's disease.

These findings indicate that smaller volumes of grey matter are associated with non-'O' blood types. As we age a reduction of grey matter volumes is normally seen in the brain, but later in life this grey matter difference between blood types will intensify as a consequence 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. However additional tests and further research are required as other biological mechanisms might be involved."

Link: http://www.sheffield.ac.uk/news/nr/blood-type-cognitive-disease-1.469296

Comments

According to the book, "The Answer is in Your Bloodtype" by Steven M. Weissberg, M.D. and Joseph Christiano, A.P.P.T. page 76 Table 5 Life Span Table as per Blood Type, there is a "most significant finding resulting from Table 5 is that there is a direct link between blood type and longevity. At this time in the United States, individuals of blood type O live 25 years longer than individuals of blood type A." The study was a group of 5,114 samples. Average death for type A was 61.6, type AB 69.5, type B 78.2 and type O lived to 86.7.

With such a large discrepancy between what you say is significant and what they say is significant, I wonder who is lying.

Posted by: Thomas Cool at June 17th, 2015 7:25 AM

@Thomas Cool: That fails even the simplest nonsense test. Think about it.

There is no such correlation; think for a moment about just how well known it would be if there was some simple thing by which one group of people lived two decades longer than another. There would be hundreds of studies supporting it, it would be in all of the text books, given how long blood types have been identifiable. That is not the situation at all.

Posted by: Reason at June 17th, 2015 7:40 AM

Thomas, I have to agree with Reason that an effect size that large just doesn't pass the sniff test. Do the authors give any citation to a study in the scientific literature for the table? The previous studies posted on FA!, including the recent review of studies on blood type and centenarianism, look to be sufficiently scattershot that it's either a wash, with individual studies falling prey to sample size problems or local founder populations, or maybe-maybe a very complex interaction between multiple genes.

Posted by: Michael at June 17th, 2015 10:39 AM

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