Study provides support for relationship between APOE4 gene and risk of Alzheimer's disease in Latinos

A brain-imaging study published today in the Archives of Neurology suggests that a major genetic risk factor for Alzheimer's disease in the Anglo population is also a risk factor for the disease in Latinos.

While a gene called APOE4 has been firmly established to increase an Anglo person's risk of Alzheimer's disease, its relationship to the disease in different Latino populations has been less clear. In previous studies, researchers from the Banner Alzheimer's Institute and their collaborators in the Arizona Alzheimer's Consortium used a brain-imaging technique called PET to show that cognitively healthy late-middle-aged carriers of the APOE4 gene have lower activity than non-carriers of the gene in brain regions known to be affected by Alzheimer's disease.

In the present study, they extended their findings to 27 Latinos with and without the APOE4 gene, mostly from Arizona's Mexican-American community. As predicted, cognitively healthy Latinos in their 50s and 60s with the APOE4 gene had lower activity than non-carriers of the gene in brain regions known to be affected by Alzheimer's disease.

"This study provides support for the relationship between the APOE4 gene and the risk of Alzheimer's disease in Latinos," said Dr. Jessica Langbaum, staff scientist at the Banner Alzheimer's Institute and the study's lead author. "It also shows how brain imaging techniques can be used in healthy people to evaluate genetic and non-genetic risk factors for this disorder."

Latinos are about 1.5 times more likely than Anglos to develop Alzheimer's disease, according to the Alzheimer's Association. Alzheimer disease is the most common form of dementia. Between the years 2000 and 2050, the number of affected Latinos is projected to increase by 600 percent. Latinos may be at higher risk due to higher amounts of diabetes mellitus, obesity, cardiovascular disease and hypertension, each of which is also a risk factor for Alzheimer's disease.

The researchers have proposed using the same brain imaging techniques in healthy APOE4 carriers to evaluate promising treatments to prevent Alzheimer's disease without having to wait many years to determine whether they go on to develop symptoms. Among other things, the present study supports the inclusion of APOE4 carriers from Latino community in these studies.