More on Mild Traumatic Brain Injuries , and a Clue Regarding Higher Rates of AD in Women

I read an article in this weeks ALZ Forum about several recent studies correlating brain injury with dementia.  The article made reference to the studies I discussed in my April 30 post, but the study that was the centerpiece of the new article addressed brain injuries that did not involve loss of consciousness.  Again, the study did not attempt to explicitly associate the dementias with AD.  What was interesting here was the way the study addressed increased rates of dementia even when the brain injury was not sufficient to cause unconsciousness.

In the same issue of ALZ Forum was an article suggesting why women are more likely to get AD than men.  This has been a mystery, and it can't be simply attributed to women living longer than men.  The idea in the article focuses on the ApoE4 gene, which is the most prominent genetic risk factor for AD.  Other variants of the ApoE gene are ApoE2 and ApoE3.  Each of us carries two copies of the gene, but they may not all be the same variant.

Apparently estrogen affects expression of the ApoE gene, but estrogen levels decrease after menopause and vary the influence of the different gene variants.  The protein synthesized from the ApoE4 gene is implicated in higher levels of inflammation in the brain, which plays a role in the development of AD.  Apparently, changes in estrogen levels can vary the how much of the protein originates from the different variants of the gene.  More protein from ApoE4 means more inflammation, hence a higher likelihood of AD.  Or that's what I got from the article.