APOE ε4 Genotype People Who Are Physically Active Have Lower Alzheimer's Risk

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Academic Journal
Main Category: Alzheimer's / Dementia
Also Included In: Neurology / Neuroscience;  Genetics
Article Date: 11 Jan 2012 - 8:00 PST


A report published Online First in the Archives of Neurology, one of the JAMA/Archives journals, found that a sedentary lifestyle is linked to greater cerebral amyloid deposition, characteristic of Alzheimer's disease (AD), amongst cognitively normal individuals with the ε4 allele of the apolipoprotein E (APOE) gene.

The background information in the article states that:

"The presence of an APOE ε4 allele is the most established genetic risk factor for Alzheimer disease (AD), with a higher percentage of individuals with AD having an ε4 allele in comparison with the general population. It has been suggested that APOE status may modify associations between lifestyle factors such as exercise engagement and risk of cognitive decline and dementia."

Denise Head, Ph.D. and her team set out to evaluate the relationship between exercise and cerebral amyloid deposition amongst patients with and without the APOE ε4 allele. They carried out APOE genotyping and surveyed 201 cognitively normal adults (135 women), between the ages of 45 to 88 years, from the Knight Alzheimer's Disease Research Center, in a questionnaire regarding physical exercise engagement over the last decade.

The researchers took samples of cerebrospinal fluid from 165 participants and performed brain amyloid imaging with positron emission tomography (PET) of the amyloid binding agent carbon 11-labeled Pittsburgh Compound B (PiB) on 163 patients.

They discovered that those patients who reported higher amounts of exercise had a lower average cortical PIB binding (binding potential values from the prefrontal cortex, gyrus rectus, lateral temporal, and precuneus regions), in comparison to patients who reported lower amounts of exercise. The findings also showed that ε4-positive participants had higher levels of cortical amyloid compared with those who were ε4-negative.

The researchers also noted a:

"..novel interaction between APOE status and exercise engagement for [11C] PiB binding [carbon 11-labeled Pittsburgh Compound B] such that a more sedentary lifestyle was significantly associated with higher [11C] PiB binding for ε4 carriers but not for noncarriers. All findings remain significant after controlling for age; sex; educational level; body mass index; the presence or history of hypertension; diabetes mellitus; heart problems, or depression; and the interval between assessments."

Previous research suggests that:

"APOE status is associated with increased risk of cognitive decline and elevated amyloid deposition. In contrast, exercise engagement has been associated with reduced risk of cognitive decline and lower levels of amyloid deposition."

The researchers conclude that:

"In summary, our findings suggest that exercise at levels recommended by the AHA [American Heart Association] may be particularly beneficial in reducing the risk of brain amyloid deposition in cognitively normal ε4-positive individuals."

Written by Petra Rattue
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

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