Middle-aged Black Americans living with both hypertension and diabetes face a significantly higher risk of neurodegeneration, according to a new study published in The Journal of Racial and Ethnic Health Disparities. The findings suggest that vascular conditions—not Alzheimer’s disease—may be the primary driver of early cognitive decline in this population.
Researchers followed 252 Black Americans from Iowa and Georgia over an 11-year period. Participants ranged in age from 45 to 79 and had diagnoses of hypertension and diabetes recorded in 2008. Blood samples collected in 2008 and again in 2019 were analyzed for neurofilament light chain (NfL), a marker of neurodegeneration, and phosphorylated tau181 (p-Tau181), a biomarker associated with Alzheimer’s disease.
The study found that individuals with both hypertension and diabetes had significantly elevated levels of NfL in 2019, and a marked increase over time. However, no association was found between these conditions and p-Tau181 levels. “Rather than being instances of AD, elevated rates of dementia among Black Americans may be largely vascular pathology caused by high rates of diabetes and high blood pressure,” wrote lead author Michelle M. Mielke, PhD, of Wake Forest University.
These findings underscore the urgent need to address vascular health disparities in Black communities. “Comorbid diabetes and hypertension exacerbate neurodegeneration and negatively impact brain health,” the researchers concluded, calling for early intervention to reduce long-term cognitive decline.
See: “Comorbid Hypertension, Diabetes Tied to Neurodegeneration in Middle-Aged Black Americans” (May 27, 2025)