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Exercise and Alzheimer's disease biomarkers in cognitively normal older adults

Authors

  • Kelvin Y. Liang BS,

    1. From the Program in Neuroscience, Division of Biology and Biomedical Sciences, Washington University, St. Louis, MO
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  • Mark A. Mintun MD,

    1. Alzheimer's Disease Research Center, Washington University, St. Louis, MO
    2. Department of Radiology, Washington University, St. Louis, MO
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  • Anne M. Fagan PhD,

    1. Alzheimer's Disease Research Center, Washington University, St. Louis, MO
    2. Hope Center for Neurological Disorders, Washington University, St. Louis, MO
    3. Department of Neurology, Washington University, St. Louis, MO
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  • Alison M. Goate PhD,

    1. Alzheimer's Disease Research Center, Washington University, St. Louis, MO
    2. Hope Center for Neurological Disorders, Washington University, St. Louis, MO
    3. Department of Neurology, Washington University, St. Louis, MO
    4. Department of Psychiatry, Washington University, St. Louis, MO
    5. Department of Genetics, Washington University, St. Louis, MO
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  • Julie M. Bugg PhD,

    1. Department of Psychology, Washington University, St. Louis, MO
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  • David M. Holtzman MD,

    1. Alzheimer's Disease Research Center, Washington University, St. Louis, MO
    2. Hope Center for Neurological Disorders, Washington University, St. Louis, MO
    3. Department of Neurology, Washington University, St. Louis, MO
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  • John C. Morris MD,

    1. Alzheimer's Disease Research Center, Washington University, St. Louis, MO
    2. Department of Neurology, Washington University, St. Louis, MO
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  • Denise Head PhD

    Corresponding author
    1. From the Program in Neuroscience, Division of Biology and Biomedical Sciences, Washington University, St. Louis, MO
    2. Alzheimer's Disease Research Center, Washington University, St. Louis, MO
    3. Department of Radiology, Washington University, St. Louis, MO
    4. Department of Psychology, Washington University, St. Louis, MO
    • Washington University, Department of Psychology, Campus Box 1125, One Brookings Dr, St. Louis, MO 63130

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Abstract

Objective

In addition to the increasingly recognized role of physical exercise in maintaining cognition, exercise may influence Alzheimer's disease (AD) pathology, as transgenic mouse studies show lowered levels of AD pathology in exercise groups. The objective of this study was to elucidate the association between exercise and AD pathology in humans using Pittsburgh compound-B (PIB), amyloid-β (Aβ)42, tau, and phosphorylated tau (ptau)181 biomarkers.

Methods

Sixty-nine older adults (17 males, 52 females) aged 55 to 88 years, were recruited and confirmed to be cognitively normal. A questionnaire on physical exercise levels over the past decade was administered to all. Cerebrospinal fluid samples were collected from 56 participants, and amyloid imaging with PIB was performed on 54 participants.

Results

Participants were classified based on biomarker levels. Those with elevated PIB (p = 0.030), tau (p = 0.040), and ptau181 (p = 0.044) had significantly lower exercise, with a nonsignificant trend for lower Aβ42 (p = 0.135) to be associated with less exercise. Results were similar for PIB after controlling for covariates; tau (p = 0.115) and ptau181 (p = 0.123) differences were reduced to nonsignificant trends. Additional analyses also demonstrated that active individuals who met the exercise guidelines set by the American Heart Association had significantly lower PIB binding and higher Aβ42 levels with and without controlling for covariates (PIB: p = 0.006 and p = 0.001; Aβ42: p = 0.042 and p = 0.046). Last, the associations between exercise engagement and PIB levels were more prominent in APOE epsilon 4 noncarriers.

Interpretation

Collectively, these results are supportive of an association between exercise engagement and AD biomarkers in cognitively normal older adults. Ann Neurol 2010;68:311–318

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