Research from Duke University finds a stronger risk for Alzheimer’s Disease among close family members of someone with the disease.
By Stephanie Soucheray
One out of every 10 Americans will develop late-onset Alzheimer’s, the degenerative disease that robs people in their 70s and 80s of their memory. If a close family member suffered from the disease, the chances increase to about 20 percent or 30 percent. The risk of developing the disease is even higher for someone with a family member who begins showing symptoms earlier.
Those are unforgiving numbers for an unforgiving disease, but researchers at Duke University are taking new steps to better understand the familial links and progression of Alzheimer’s. In a new paper published in the journal PLOS ONE Wednesday, researchers describe a study that found signs of the silent disease much earlier than expected in the brains of people with a familial history of Alzheimer’s.
“We looked for three things in the brains of people who have Alzheimer’s in their family,” explained P. Murali Doraiswamy, professor of psychiatry and medicine at Duke and author of the paper. Doraiswamy said his team looked for a buildup of Alzheimer’s telltale plaque and tangles and a shrinking of the brain’s memory center.
Doraiswamy and colleagues, including Duke undergraduate Erika Lambert, studied 257 people between the ages of 55 and 89. A positive family history of Alzheimer’s was defined as having either a sibling or parent with the disease. All participants were part of Duke’s branch of the Alzheimer’s Disease Neuroimaging Initiative (ADNI ).
Both tangles and plaque, marked by the presence of cerebrospinal fluid proteins, showed up in the brains of people genetically prone to Alzheimer’s much earlier than symptoms – usually when someone was in their 50s or 60s. Fifty percent of those with a family history of the disease met the criteria for preclinical Alzheimer’s based on their fluid samples, while only 20 percent of those without family history did. The area of the brain associated with memory was similar in all healthy people, suggesting changes to memory centers occur when the disease becomes symptomatic.
“If we know a time frame to the disease,” said Doraiswamy, “it will be easier to employ the right diagnostic test to monitor at-risk patients by targeting these biomarkers. We’ll know cut points of when fluid becomes abnormal, and we can establish a timeline for when to test people.”
Doraiswamy said this study will lead the way in making diagnostic tests available in the future; but right now, the tests can’t offer anyone with a family history of Alzheimer’s hope.
“We don’t have a way to prevent the disease except to recommend a healthy lifestyle,” said Doraiswamy. “What’s good for the brain are the same things that are good for the heart, like diet and exercise.”
Doraiswamy said people with a family history of Alzheimer’s should be wary of websites that offer tests for the disease, and to remember that they still have a strong chance of having a healthy brain well into old age.
Moreover, Doraiswamy said this paper ushers in a new wave of longitudinal studies taking place across the country that could help identify preventative interventions for those at risk for Alzheimer’s.
“I do think people with a family history should seek out clinical trials,” said Doraiswamy. “It helps science and themselves better understand the disease.”
Duke University, besides being an ADNI site, also hosts the Enlighten study, which is looking at a combination of diet and exercise on aging, hypertension and cognitive abilities.
Doraiswamy also said people should look for future trials featuring antibody therapies, which would pull the plaque out of a person’s brain before the disease begins to do its damage.
“And talk with your family,” said Doraiswamy. “Understand your risk.”