In their analysis, the researchers found that physical activity was associated with enhanced cognitive function, and that this relationship was differentially influenced by the person's APOE genotype: non-E4 carriers and people with one copy of E4 performed better than people with two copies of E4.
Alzheimer's Risk Gene May Reduce Benefits of Physical Activity to Cognitive Ability
While the relationship of physical activity with cognitive performance as we age is a subject of considerable research, much less is known about how this relationship is impacted by the Alzheimer's risk gene Apolipoprotein E (APOE). The APOE gene comes in three types, or alleles, known as e2, e3, and e4. Each person gets one type of APOE from each parent, making the possible combinations: e2/e2, e2/e3, e2/e4, e3/e3, e3/e4, e4/e4. Having two copies of e4 conveys the highest risk for Alzheimer's; having one e4 also raises one's risk. E3 is the most common type. E2, though rare, is thought to be protective.
Thomas Obisesan, MD, MPH, FAAFP, Chief of the Division of Geriatrics at Howard University Hospital and professor of medicine at Howard University College of Medicine, Washington, D.C., and colleagues examined this issue using data from The Third National Health and Nutrition Examination Survey (NHANES III, 1988-1994). They identified 1,799 men and women age 60 and older who had data on levels of aerobic-related physical activity (AR-PA), such as walking, jogging, bicycling or swimming; mental status test scores; and APOE genotype.
In their analysis, the researchers found that physical activity was associated with enhanced cognitive function, and that this relationship was differentially influenced by the person's APOE genotype: non-E4 carriers and people with one copy of E4 performed better than people with two copies of E4. After adjusting for age, ethnicity, severe chronic medical illness, lean body mass, and education, aerobic physical activity continued to show a statistically significant association with cognitive function in non-E4 carriers but not in people with E4 (any combination)
"In our nationally representative sample, persons who reported higher levels of aerobic physical activity had better memory than those who reported no such activity.
This was especially true in those people who didn't have the APOE-e4 Alzheimer's risk gene," Obisesan said.
"Because physical activity is a low-cost, low-risk, readily available intervention, it may prove to be an important public health strategy to reduce or prevent memory loss and other symptoms of mental decline in the elderly. Future rigorous clinical trials are needed to confirm these findings," Obisesan added.
Thomas Obisesan, et al – Aerobic-related physical activity interacting with apolipoprotein E genotypes, is associated with better cognitive function in a nationally representative sample: The Third National Health and Nutrition Examination Survey (NHANES III) (Funder: National Institutes of Health)
About ICAD 2009
The 2009 Alzheimer's Association International Conference on Alzheimer's Disease (ICAD 2009) brings together more than 5,000 researchers from 60 countries to share groundbreaking research and information on the cause, diagnosis, treatment and prevention of Alzheimer's disease and related disorders. As a part of the Association's research program, ICAD 2009 serves as a catalyst for generating new knowledge about dementia and fostering a vital, collegial research community. ICAD 2009 will be held in Vienna, Austria at Messe Wien Exhibition and Congress Center from July 11–16.
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Bob DeMarco is the Founder of the Alzheimer's Reading Room and an Alzheimer's caregiver. The blog contains more than 2,255 articles with more than 272,100 links on the Internet. Bob resides in Delray Beach, FL.
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Original content Bob DeMarco, the Alzheimer's Reading Room