Heredity, Environment Play Alzheimer's Role

African Americans whose parents have Alzheimer's Disease are far more likely to also contract the disease than other races, according to a recent study conducted at Oregon Health & Science University.

The reasons for this occurrence can be attributed both to genetics and the social environment, said Fred Miller, director of the African American Dementia and Aging project at Oregon Health & Science University.

"There's a greater familial risk among African Americans," said Miller, who has been working with a group of 100 African Americans in an aging and memory loss study for six years. "Genetic and environmental factors work differently (than in other races) to cause Alzheimer's Disease in African Americans."

For instance, researchers have found that African Americans who have a gene protein called APOE 44 may have a 30 percent greater chance of having Alzheimer's Disease than other races, Miller said. However, he added, more research is needed to determine how the gene affects other races.

African Americans with high blood pressure or high cholesterol are twice as likely to contract Alzheimer's than other races, Miller said. Those with both conditions are four times as likely to suffer from Alzheimer's or some other form of dementia related to vascular illness.

In addition, African Americans have a 60 percent higher risk of type 2 diabetes, which also contributes to vascular disease and could lead to Alzheimer's.

How much these conditions — and Alzheimer's itself — are caused by stress and other "traditional" practices in the African American culture is one of the questions Miller is pursuing.

"We found there is a clear relationship between stress and memory, but the question is does stress … due to racism and prejudice cause permanent memory problems? We can't answer that yet," Miller said.

Those in the study undergo an extensive annual physical exam that tests the heart, blood and memory. They have a neuropsychology test to determine how they see themselves fitting within their traditional culture, and they go through an MRI, where the hippocampus in the brain is measured. Scientists have discovered that the hippocampus in Alzheimer's patients shrinks as the disease progresses. The hippocampus plays a role in memory and navigation.

Miller also is looking at the stress hormone called cortisol. While a specific stressful incident can enhance the memory of a person who can recall the incident as if it were happening at that moment, the long-term effects of constant stress can be toxic to the brain and cause the hippocampus to shrink, he said.

In the study, Miller has tested the participants in terms of how they practice traditional African American values, beliefs and practices and how much they have melded with the dominant White culture in the Portland and Vancouver area.

Although African Americans have been in the United States since 1619, they have actually only been "free" since Congress passed civil rights legislation 40 years ago, Miller noted. Until then, most African Americans were slaves until 1865 or were segregated from the rest of society.

"African Americans are like immigrants," Miller added. "My argument is that they are still making the transition."

Miller found that 44 of his participants are still immersed in the original African American culture: They tend to stay within the local African American community, they don't speak formal English and their dialect is of the ethnic region where they originally came from.

A person's culture and language make a difference when they see a doctor, Miller noted. A doctor may not understand an African American patient who says, "I got gravel," meaning a urinary infection. Or, the patient might say, "My ankles and legs are strutting," which means they are cramping.

"How can doctors appreciate a patient's symptoms if they can't understand what the patient is saying?" Miller asked.

He hopes to enhance communication between doctors and their African American patients. In addition, if the seniors in the study agree, he sends the results of the physical exams to their personal physicians.

"Our hope is to ask these physicians how they can better communicate with their patients. We talked to doctors of traditional African American patients, and they tell us, 'They come to me, but they don't give me the information I need,' " Miller said.

This lack of communication may be one reason that vascular-related symptoms may not be monitored as early as they could be or that Alzheimer's isn't diagnosed until the later stages in African American patients, he added.

Being caught between the traditional and dominant cultures also may lead to more ongoing stress for African Americans, according to Miller. Many of the participants may straddle the cultural gulf, for instance, by following traditional religious beliefs and practices but being highly educated. In addition, as they age, they may become even more traditional and involve themselves more with the African American culture and fall away from participating in the dominant culture.

Although the study originally was slated to last only five years, it has been extended to 10 years, Miller said. By then, he hopes to be able to study more of his participants who may contract Alzheimer's. Over 10 percent of all persons over 65, and half of those over 85 have Alzheimer's Disease.

Also involved in the African American Dementia and Aging Project are: Dr. Jeffrey Kaye, M.D.; Barbara Stewart, Ph.D.; Georgene Siemsen, R.N.; and Dr. Clifford Coleman, M.D.

Eventually, Miller said, he hopes to replicate the results of the study by conducting it in the southern and eastern United States. The results could add more information than ever about the health of African Americans.
"At no time in the United States has the health of African Americans ever equaled or even come close to that of European Americans," Miller added.

To learn more about Alzheimer's Disease, the Alzheimer's Association of Oregon offers classes on the early stages, living with a loved one with Alzheimer's Disease and the disease's later stages. Call 503-413-7115 or visit www.alzheimers-oregon.org.

Legacy Health System also offers classes for caregivers of people with Alzheimer's Disease and other chronic or terminal conditions. The classes help caregivers learn the tools for thriving on their own while giving care either directly or by long distance. Call 503-335-3500 or visit www.legacyhealth.org and ask for the Powerful Tools for Caregiving classes.