January 08, 2019
A study published Monday might have found an explanation for why African-Americans may be twice as likely as Caucasian Americans to develop Alzheimer's disease.
Researchers at the Washington University School of Medicine in St. Louis have determined racial disparities between African-Americans and Caucasians in a biomarker used to identify Alzheimer's disease, Medical Xpress reports. The research, which was published in JAMA Neurology, suggests that current methods used to diagnose the illness may not effectively apply to African-Americans.
Researchers examined 1,255 black and white people to find that cerebrospinal fluid from African-Americans generally contained lower levels of the biomarker tied to Alzheimer’s. That said, these lower levels didn’t serve to protect black participants from the disease, either, NPR reports.
NPR explains the research method further:
Researchers used brain scans and samples of spinal fluid to look for two biological hallmarks of Alzheimer's — amyloid, a protein that forms sticky plaques in the brain and a protein called tau, which forms toxic tangles inside brain cells.
The concern is that Alzheimer's is likely under-recognized in African-Americans because the group as a whole seems to have lower levels of the brain protein tau, rendering them unable to meet the threshold to be diagnosed when the disease already has begun to develop in their brains, Medical Xpress states.
According to Quartz:
Researchers also found that even though a form of the APOE gene known as APOE4 has been linked to higher risks of Alzheimer’s in white populations, African-Americans who had APOE4 had lower levels of tau. This suggests that APOE4 may not be as big of a risk factor for African-Americans that it is for white people, according to John Morris, a neuroscientist at Washington University and lead author of the paper.
While these findings have the potential to suggest that Alzheimer’s works differently in different racial groups, the study was limited.
For example, according to NPR:
It couldn’t fully account for the effects of some other known Alzheimer's risk factors — including hypertension, diabetes and obesity — or some suspected risk factors, including stress and poverty. Also, of the participants, only 173 African-Americans were represented. Further, researchers were only able to obtain spinal fluid samples from half that group.
“We now need to make our research cohorts representative of the populations so we can begin to ask and address these questions,” said Dr. John Morris, an author of the study and director of the Knight Alzheimer's Disease Research Center at Washington University in St. Louis, per Quartz.