title: Cardiorespiratory fitness and brain diffusion tensor imaging in adults over 80 years of age.
abstract: A positive association between cardiorespiratory fitness (CRF) and white matter integrity has been consistently reported in older adults. However, it is unknown whether this association exists in adults over 80 with a range of chronic disease conditions and low physical activity participation, which can influence both CRF and brain health. This study examined whether higher CRF was associated with greater microstructural integrity of gray and white matter in areas related to memory and information processing in adults over 80 and examined moderating effects of chronic diseases and physical activity. CRF was measured as time to walk 400 m as quickly as possible with concurrent 3T diffusion tensor imaging in 164 participants (57.1% female, 40.3% black). Fractional anisotropy (FA) was computed for cingulum, uncinate and superior longitudinal fasciculi. Mean diffusivity (MD) was computed for dorsolateral prefrontal cortex, hippocampus, parahippocampus, and entorhinal cortex. Moderating effects were tested using hierarchical regression models. Higher CRF was associated with higher FA in cingulum and lower MD in hippocampus and entorhinal cortex (β, sex-adjusted p: -0.182, 0.019; 0.165, 0.035; and 0.220, 0.006, respectively). Hypertension attenuated the association with MD in entorhinal cortex. Moderating effects of chronic diseases and physical activity in walking and climbing stairs on these associations were not significant. The association of higher CRF with greater microstructural integrity in selected subcortical areas appears robust, even among very old adults with a range of chronic diseases. Intervention studies should investigate whether increasing CRF can preserve memory and information processing by improving microstructure and potential effects of hypertension management.
authors.affiliation: Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA. Electronic address: qu.tian@nih.gov.
authors.forename: Qu
authors.initials: Q
authors.lastname: Tian
authors.affiliation: Intramural Research Program, National Institute on Aging, Baltimore, MD 21225, USA.
authors.forename: Eleanor M
authors.initials: EM
authors.lastname: Simonsick
authors.affiliation: Department of Psychology, University of Pittsburgh, Pittsburgh, PA 15260, USA.
authors.forename: Kirk I
authors.initials: KI
authors.lastname: Erickson
authors.affiliation: Departments of Psychiatry, Bioengineering, and Clinical and Translational Science, University of Pittsburgh, Pittsburgh, PA 15213, USA.
authors.forename: Howard J
authors.initials: HJ
authors.lastname: Aizenstein
authors.affiliation: Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Nancy W
authors.initials: NW
authors.lastname: Glynn
authors.affiliation: Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Boudreau
authors.affiliation: Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Anne B
authors.initials: AB
authors.lastname: Newman
authors.affiliation: Sticht Center on Aging, Section on Gerontology and Geriatric, Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA.
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Kritchevsky
authors.affiliation: Departments of Psychiatry, Neurology and Epidemiology, University of California, San Francisco, San Francisco, CA 94121, USA.
authors.forename: Kristine
authors.initials: K
authors.lastname: Yaffe
authors.affiliation: Intramural Research Program, Laboratory of Epidemiology, Demography, and Biometry, National Institute on Aging, Bethesda, MD, USA.
authors.forename: Tamara
authors.initials: T
authors.lastname: Harris
authors.affiliation: Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Caterina
authors.initials: C
authors.lastname: Rosano
mesh_terms: D000369:Aged, 80 and over; D016880:Anisotropy; D001921:Brain / Q000033:anatomy & histology*; D002908:Chronic Disease; D038524:Diffusion Magnetic Resonance Imaging; D056324:Diffusion Tensor Imaging; D005260:Female; D066128:Gray Matter / Q000033:anatomy & histology; D006801:Humans; D006973:Hypertension / Q000473:pathology / Q000503:physiopathology; D008297:Male; D010809:Physical Fitness / Q000502:physiology; D016138:Walking / Q000502:physiology; D066127:White Matter / Q000033:anatomy & histology
keywords: Cardiorespiratory fitness; Diffusion tensor imaging; Microstructural integrity; Neuroepidemiology; Very old adults