Exercise Can Delay Cognitive Decline in those at Genetic Risk for Alzheimer’s
While many factors are likely involved, genes play an important role in the development of Alzheimer’s disease. For those that carry a high-risk gene for the late-onset form of the disease, regular physical activity may promote brain changes that can protect against cognitive decline, finds a study conducted at the University of Wisconsin-Milwaukee.
APOE Gene is Risk Factor for Late-Onset Alzheimer's Disease Development
There is already evidence to suggest that regular exercise is associated with maintenance of cognitive function across a life span, but the study is one of the first to assess the effects of physical activity on those at a genetically higher risk for developing Alzheimer’s.
Lead researcher J. Carson Smith, an assistant professor of health sciences, compared brain activation using functional magnetic resonance imaging (fMRI) during memory processing in four separate groups of healthy 65 to 85 year olds. The participants were divided according to their risk status based on the presence of the apolipoprotein E-epsilon4 (APOE-4) allele.
The APOE gene is located on chromosome 19 and is involved in making a protein that helps carry cholesterol in the bloodstream. The epsilon 4 allele appears to influence the age at which Alzheimer’s disease begins. It occurs in about 40% of all people who develop late-onset Alzheimer’s disease and is present in about 25 to 30 percent of the population. A blood test is available that can identify those that carry APOE-4, but it is not yet possible to predict who will or will not go on to develop Alzheimer’s disease.
For those participants who carried high-risk gene, those who were more physically active had greater brain activity in memory-related regions than those who were sedentary. “Using more areas of the brain may serve as a protective function, even in the face of disease processes,” said Smith.
The Alzheimer’s Association estimates that today, just over 5 million Americans have Alzheimer’s disease and that number is expected to increase to 7.7 million by the year 2030.
The study, funded by the National Institutes of Health and the National Institute on Aging, will be published in the January 2011 issue of the journal NeuroImage.