A study from researchers at the Mayo Clinic, published in the February issue of the Journal of Alzheimer’s Disease, may show some insights into the genetics of the disease in Black Americans who develop the disease after age 65.

According to the Alzheimer’s Foundation, there are over 5.4 million people currently living with the disease, which is the sixth-leading cause of death in the United States.  African-Americans, however, have the highest rates of Alzheimer’s of any racial or ethnic group and, for older African-Americans, it is the fourth-leading cause of death. They are also twice as likely to develop late-onset Alzheimer’s.

According to senior investigator Dr. Nilufer Ertekin-Taner, M.D., Ph.D., a neurogeneticist and neurologist at the Mayo Clinic’s Florida campus who worked on the study, althugh the reasons for these high rates of Alzheimer’s in the Black community remains unknown, she cites “higher vascular risk factors such as hypertension, diabetes, high cholesterol, as well as differences in genetics and/or differences in socioeconomic factors” as some of the many possible reasons for the disease’s significant impact, according to NBC News.

“It is likely that the reason is some combination of these factors, all of which require further exploration,” Dr. Ertekin-Taner told NBC News.  She also adds that though African-Americans remain disproportionately affected, there is very little research available or being conducted on the impact in the Black community in comparison to their White counterparts.  “Despite being the largest published study of this type in this population to our knowledge, this study is still much smaller than similar ones being conducted in Caucasians.”

In addition to the emotional toll Alzheimer’s disease takes on families, the financial toll is high as well, with estimates for the cost of care for an individual patient running somewhere around $20,000 per year. And the annual costs related to the disease currently running somewhere around $200 billion for patients in the U.S.

Researchers, however, caution against rushing out to get genetic testing in families. Dr. Ertenkin-Tanner suggests that unless there is strong family history of early Alzheimer’s disease in multiple generations, “we do not advocate genetic testing for the known early-onset familial Alzheimer’s genes. This situation will likely change when we have more targeted therapies for Alzheimer’s disease,” she says.

Currently, there is no cure or way to slow down the progression of the disease.