Community Outreach

Georgia: Alzheimer's Disease in the African American Community

Atlanta Daily, Cynthia Post

Audience served: African American community in Atlanta, Georgia.

Clinical Trial Tries To Shed Light On Impact Of Genetics On Alzheimer’s Disease by Cynthia Post, Atlanta Daily World.

Morehouse School of Medicine researchers hope to recruit more African-Americans for a clinical trial involving genetics and Alzheimer’s disease. They confirm a higher rate of Alzheimer’s disease among African-Americans. This is probably not due to any differences between ethnic groups in either the action or prevalence of genes known to be associated with Alzheimer’s. The group is looking at alternative explanations such as environmental factors. A recent analysis suggests that about 3.4 million Americans age 71 and older — one in seven people in that age group - have dementia, and 2.4 million of them have Alzheimer’s disease.

The study, supported by the National Institutes of Health, was the latest in a series of analyses attempting to assess the prevalence of dementia and Alzheimer’s disease, the most common form of dementia.

Current research shows Alzheimer’s disease is more prevalent among African-Americans than among whites - with estimates ranging from 14 percent to almost 100 percent higher.

Since 1995, Morehouse School of Medicine has participated in the Multi Institutional Research of Alzheimer Genetic Epidemiology, or MIRAGE, Project. The Project, funded by the National Institute on Aging since 1991, is the largest genetic epidemiology study of Alzheimer’s disease in the world. The Project has collected detailed clinical, risk factor and family history information on more than 2,500 rigorously examined Alzheimer’s disease patients.

The Atlanta clinical trial has collected information on 150 African-American families and 300 individuals, said Dr. Abimbola Akomalafe, associate professor of clinical medicine, Morehouse School of Medicine.

Apolipoprotein E (APOE) is a well-studied gene that is a susceptibility gene in late on set Alzheimer’s disease. APOE has functions throughout the body, transporting cholesterol, regulating the immune system, aiding in nerve regeneration, and metabolism. There are four different forms of the APOE genes.

Inheriting one of these forms called E4 increase a person’s risk of developing Alzheimer’s disease, several studies have demonstrated this and Morehouse School of Medicine is one of the recruiting sites for the genetic epidemiology study funded by the National Institutes of Health and African-Americans recruited in this studies have also demonstrated similar findings, said Akomalafe.

Inheriting two copies of E4 increases risk of developing Alzheimer’s disease 12- to 15-fold. People with two copies of E4 also tend to develop Alzheimer’s disease earlier in life than the general population. The E4 version of APOE is present in about 15 percent of all Caucasians and is even more common in people of African descent. However, not all people who have Alzheimer’s disease also have the E4 version of APOE this means that other environmental or genetic factors are also required in order for a person to develop AD.

Several other candidate genes have been reported as risk factors, including the Nitric oxide synthase 3 (NOS3) genes. Located on chromosome 7q35, NOS3 encodes endothelial NOS (eNOS). Nitric oxide (NO) accounts for the biologic activity of endothelium-derived relaxing factor (EDRF). Nitric oxide is synthesized in endothelial cells from L-arginine by nitric oxide synthase (NOS). Endothelium-derived relaxing factor (EDRF) is important in regulation of vasomotor tone and blood flow by inhibiting smooth muscle contraction and platelet aggregation, said Akomalafe.

“Our study suggests that the presence of GG genotype of the rs 1799983 polymorphism in the NOS3 coding region, may be a risk factor for the development of Alzheimer’s disease in our African-American population,” said Akomalafe. “No previous studies to date have looked at the African-American population in relation to this gene and we examined multiple SNPs spanning the gene.”

Individuals, siblings and families are encouraged to participate in the clinical trial, said Akomalafe.

“Genetic risk factors or some combination of genetic and non-genetic risk factors, may allow us to identify vulnerable individuals and focus preventive therapies upon those who have the highest risk,” said Akomalafe. “Results from this clinical trial may have immediate impact on the development of new treatment or prevention strategies.”

Individuals with a family history of dementia – or those who want to prevent memory loss – can become more educated about genetics and Alzheimer’s disease.

“As people mature their risk of heart attacks, strokes and memory loss increase,” said Dr. Floyd B. Willis, chair, Department of Family Medicine, Mayo Clinic Jacksonville. “Genetics and personal choices, such as tobacco use, poor diet and inactivity and alcohol consumption, are linked to the aging process.

“These personal choices may also contribute to unhealthy brain aging,” continued Willis. “Preventative measures, such as eating well and staying mentally and physically active, should become everyday practices to combat memory loss.”

Memory loss such as Alzheimer’s disease occurs in stages - early, middle and late - and can progress at different rates in each person, said Willis.

The following are tips for brain health to help decrease the chance of memory loss: mental exercise (reading, doing puzzles, playing memory games); physical exercise at a safe pace (walking, bicycling); eat a balanced diet that includes: a handful of nuts (almonds, walnuts, pecans), fish two to three times per week (salmon, halibut, mackerel), curry spices, foods high in antioxidants (grape juice, pomegranate juice, beans, berries, green tea), plenty of water, B-complex vitamins (one per day), Vitamin C (500 mg per day); write down your thoughts; talk with friends and family; and have regular check-ups.

For more information on Morehouse School of Medicine’s clinical trial regarding genetics and Alzheimer’s disease, contact Jolita Wainwright at 404-752-1877.

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