Physical Activity Seems to Protect Those Genetically Prone to Alzheimer's

A physically active lifestyle is associated with decreased cerebral amyloid deposition—a trait of Alzheimer's disease—in cognitively normal individuals who have a genetic predisposition to develop the disease, researchers have found. Likewise, a sedentary lifestyle was linked to increased cerebral amyloid deposition.

The study, which was carried out at the Knight Alzheimer's Disease Research Center at Washington University in St. Louis, involved 201 cognitively normal adults between the ages of 45 and 88. To gauge levels of amyloid buildup in the brain, samples of cerebrospinal fluid were collected from 165 participants, and amyloid imaging was conducted on 163.

Participants were categorized as low or high exercisers based on a questionnaire regarding their level of activity over the previous decade. They also received genetic testing to determine whether they carried the ε4 allele of the apolipoprotein E (APOE-4) gene, which predisposes one to develop Alzheimer’s disease.

The researchers found that carriers of the APOE-4 gene who were categorized as high exercisers had a lower average buildup of amyloid than low exercisers. In addition, low exercisers who were carriers of the gene had an elevated buildup of amyloid while low exercisers who were not carriers did not. These results remained significant after the researchers accounted for numerous factors such as age, sex, educational level, body mass index, the presence or history of hypertension, diabetes mellitus, heart problems, or depression, and the interval between assessments.

“Collectively, these results suggest that cognitively normal sedentary APOE 4—positive individuals may be at augmented risk for cerebral amyloid deposition,” the authors conclude in the study abstract.

The study was published online earlier this week by Archives of Neurology.