Kinesiophobia And White Matter Integrity In Sedentary Middle-Aged Adults At Heightened Risk For Alzheimer’s Disease

White matter integrity (WMI) in the brain is critical for efficient cognitive processing, is associated with physical activity (PA), and is vulnerable to age- and disease-related declines. In sedentary populations, assessing kinesiophobia-related barriers to PA (i.e., fear avoidance of PA), rather than PA, may be important for identifying how chronic disengagement in PA is related to WMI. PURPOSE: To investigate the relationship of WMI with kinesiophobia-related barriers to PA and self-reported PA in sedentary (< 90 min/week of PA) middle-aged adults with a family history of Alzheimer’s disease (AD). METHODS: Participants (n = 79, 13 males, Mage = 56.2 ± 5.9 yrs) completed diffusion tensor neuroimaging (DTI), the Kinesiophobia Causes Scale (KCS), and the International Physical Activity Questionnaire (IPAQ). Single-shell DTI was acquired with 32 directions at b = 1000 mm/s2 and b = 0 mm/s2. Standard preprocessing and DTI metric calculation (i.e., fractional anisotropy [FA], mean diffusivity [MD], axial diffusivity [AxD], and radial diffusivity [RD]) were completed using FSL. Tract-based spatial statistics analyses were performed to examine correlations between WMI and KCS Biological Domain, KCS Psychological Domain, KCS Total Score, and IPAQ Total Score, controlling for age and sex, within a region of interest mask relevant for aging, cognition, and PA (i.e., corpus callosum, fornix, hippocampal cingulum). RESULTS: Within the corpus callosum, greater FA was related to lower KCS Biological Domain score (p = .04), greater MD and AxD were related to higher KCS Psychological Domain score (ps < .01), and greater RD was related to higher KCS Total Score (p = .03). There was no relationship between WMI and IPAQ (p = .12). CONCLUSIONS: In sedentary, middle-aged adults at a heightened risk for AD, greater kinesiophobia-related barriers to PA, but not PA itself, are related to worse WMI in the corpus callosum, a region vulnerable to age- and AD-related declines. Measuring kinesiophobia-related barriers to PA, along with PA, in sedentary populations may therefore be an informative tool to discover the relationship between PA behaviors and brain health. Future studies should explore strategies to reduce perceived barriers to PA in midlife, which may lead to increased PA and have long-term benefits for brain health. NIH/NIA R01AG058919