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Abstract
Objective: To examine whether engagement in physical activity might favorably alter the age-dependent evolution of Alzheimer disease (AD)-related brain and cognitive changes in a cohort of at-risk, late-middle-aged adults.
Methods: Three hundred seventeen enrollees in the Wisconsin Registry for Alzheimer's Prevention underwent T1 MRI; a subset also underwent 11C-Pittsburgh compound B–PET (n = 186) and 18F-fluorodeoxyglucose–PET (n = 152) imaging. Participants' responses on a self-report measure of current physical activity were used to classify them as either physically active or physically inactive based on American Heart Association guidelines. They also completed a comprehensive neuropsychological battery. Covariate-adjusted regression analyses were used to test whether the adverse effect of age on imaging and cognitive biomarkers was modified by physical activity.
Results: There were significant age × physical activity interactions for β-amyloid burden (p = 0.014), glucose metabolism (p = 0.015), and hippocampal volume (p = 0.025) such that, with advancing age, physically active individuals exhibited a lesser degree of biomarker alterations compared with the physically inactive. Similar age × physical activity interactions were also observed on cognitive domains of Immediate Memory (p = 0.042) and Visuospatial Ability (p = 0.016). In addition, the physically active group had higher scores on Speed and Flexibility (p = 0.002) compared with the inactive group.
Conclusions: In a middle-aged, at-risk cohort, a physically active lifestyle is associated with an attenuation of the deleterious influence of age on key biomarkers of AD pathophysiology. However, because our observational, cross-sectional design cannot establish causality, randomized controlled trials/longitudinal studies will be necessary for determining whether midlife participation in structured physical exercise forestalls the development of AD and related disorders in later life.
GLOSSARY
- Aβ=
- β-amyloid;
- Aβi=
- β-amyloid indeterminate;
- AD=
- Alzheimer disease;
- DVR=
- distribution volume ratio;
- FDG=
- 18F-fluorodeoxyglucose;
- FH=
- parental family history;
- MET=
- metabolic equivalent;
- MNI=
- Montreal Neurological Institute;
- PCC=
- posterior cingulate cortex;
- PiB=
- 11C-Pittsburgh compound B;
- WRAP=
- Wisconsin Registry for Alzheimer's Prevention
Footnotes
Go to Neurology.org for full disclosures. Funding information and disclosures deemed relevant by the authors, if any, are provided at the end of the article.
- Received April 15, 2014.
- Accepted in final form August 6, 2014.
- © 2014 American Academy of Neurology
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