Affiliations: [a] Department of Physical Therapy and Rehabilitation Sciences University of Kansas School of Allied Health, Kansas City, KS, USA | [b] Department of Neurology, University of Kansas School of Medicine, Kansas City, KS, USA | [c] Hoglund Brain Imaging Center, University of Kansas School of Medicine, Kansas City, KS, USA
Correspondence:
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Correspondence to: Jeffrey M. Burns, MD, University of Kansas School of Medicine, Department of Neurology, MSN 1065, 2100 W. 36th Ave, Suite 110, Kansas City, KS 66160, USA. Tel.: +1 913 588 0555; Fax: +1 913 945 5035; E-mail: jburns2@kumc.edu.
Abstract: Accelerated bone loss is associated with Alzheimer's disease (AD). Although the central nervous system plays a direct role in regulating bone mass, primarily through the actions of the hypothalamus, there is little work investigating the possible role of neurodegeneration in bone loss. In this cross-sectional study, we examined the association between bone mineral density (BMD) and neuroimaging markers of neurodegeneration (i.e., global and regional measures of brain volume) in early AD and non-demented aging. Fifty-five non-demented and 63 early AD participants underwent standard neurological and neuropsychological assessment, structural MRI scanning, and dual energy x-ray absorptiometry. In early AD, voxel-based morphometry analyses demonstrated that low BMD was associated with low volume in limbic grey matter (GM) including the hypothalamus, cingulate, and parahippocampal gyri and in the left superior temporal gyrus and left inferior parietal cortex. No relationship between BMD and regional GM volume was found in non-demented controls. The hypothesis-driven region of interest analysis further isolating the hypothalamus demonstrated a positive relationship between BMD and hypothalamic volume after controlling for age and gender in the early AD group but not in non-demented controls. These results demonstrate that lower BMD is associated with lower hypothalamic volume in early AD, suggesting that central mechanisms of bone remodeling may be disrupted by neurodegeneration.
Keywords: Alzheimer's disease, bone density, hypothalamus, voxel-based morphometry
