Hypertension and Disparities in AD

It is well-established that the incidence of Alzheimer’s Disease (AD) is disproportionately higher among Black Americans. Studies have pointed to possible explanations for this disparity, such as diabetes, heart disease, and hypertension. However, many of these explanations are based on correlations. The field of neuroscience has therefore been left lacking a quantitative explanation. In a paper written by researchers at Duke University, they apply the Blinder-Oaxaca algorithm, a statistical model, to investigate the potential causes for this disparity. They analyzed the influence of different diseases and health conditions including hypertension, diabetes, renal disease, depression, cerebrovascular disease, cardiovascular disease, and traumatic brain injury, all of which are more prevalent in Black Americans than white Americans. The study used an algorithm to separate the impact of these diseases on AD risk into two different components: exposure and vulnerability. In this context, “exposure” refers to the incidence of the diseases themselves in Black and white Americans. By evaluating the influence of disease exposure on AD risk, the researchers sought to determine whether AD incidence is higher in Black Americans because there are more cases of these health conditions in Black populations. On the other hand, “vulnerability” refers to the impact of a disease on the risk of developing Alzheimer's Disease, where the researchers wanted to determine if, for example, having diabetes would increase the risk of developing AD to a greater degree in a Black American than a white American or vice versa.

Of the diseases analyzed, they found that hypertension had the greatest influence on the differences between the incidence of AD in Black and white Americans, notably larger than the impact of all the other diseases of interest combined. In other words, between two people with hypertension, a Black American has a higher risk of developing Alzheimer’s disease due to hypertension compared to a white American. Though the reason for this difference in risk increase is not yet fully understood, it is clear that managing hypertension is important to all older adults. It may be especially important for Black Americans, as this may be a key factor reducing the risk of AD.

Additionally, medications for hypertension, including ACE inhibitors and angiotensin II receptor blockers (ARBs) have not only been found to effectively treat hypertension, but also reduce the risk of development of neurofibrillary tangles associated with development of Alzheimer’s Disease. However, prescription and adherence rates for these medications are lowest in Black Americans. It is essential that Black Americans get the attention they are lacking in treating hypertension, which will in turn help decrease the rates of Alzheimer’s disease in the population.

Article of Interest:

Akushevich I, Kolpakov S, Yashkin AP, Kravchenko J. Vulnerability to Hypertension Is a Major Determinant of Racial Disparities in Alzheimer's Disease Risk. Am J Hypertens. 2022;35(8):745-751. doi:10.1093/ajh/hpac063