It is worth discussing the higher or lower risks of developing certain forms of dementia as part of a larger conversation involving genetically inherited diseases. The accepted conclusion is that the earliest origins of AD can be traced back to Volga German ancestry. However, AD has been found in every ethnic group that has been systematically studied, which has included West Europeans (not just Germans), Japanese, Mexicans, Hispanics (especially with stronger continental Spanish/West European blood ties), and Ashkenazic Jews (about 80% of Jews are Ashkenazic, the rest of Sephardic, which is more Iberian peninsula-origin).
Current studies are examining which genes are more likely responsible by ethnic group. In other words, even though every ethnic group can be susceptible to Alzheimer’s disease, the reason may not be the same across all groups. For most, it is the apoE-4 gene. In this case, Caucasians had a stronger apoE-4 gene-related reason for developing AD than those of African descent. Japanese-descent subjects had an even stronger association than Caucasians. This doesn’t mean all other ethnic groups are off the hook because there are variations of this apoE-4 gene (such as E2 and E3) that could be equivalent (or greater) culprits for specific groups, such as African- or Hispanic-descent.
What does this all mean? It means that for those interested in genetic testing to predict the likelihood of developing AD, it may not be worth the money for incomplete or possibly misleading results. So far, the most understood gene is the apoE-4 gene, but even that isn’t without its mysteries. That means for someone to test “clear” on the apoE-4 gene doesn’t mean there is no risk for AD because perhaps one of those mysterious parts of E4 were not yet understood or it was another E-variation that hasn’t been discovered at all. Better safe than sorry and focus on the preventable factors in the meantime.