TY - JOUR
T1 - Sedentary behavior associated with reduced medial temporal lobe thickness in middle-aged and older adults
AU - Siddarth, Prabha
AU - Burggren, Alison C.
AU - Eyre, Harris A.
AU - Small, Gary W.
AU - Merrill, David A.
N1 - Funding Information:
The following agencies supported the design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation of the manuscript: National Institutes of Health grants MH077650, AT003480, P01-AG024831, AG13308, P50 AG 16570, MH/ AG58156, AG10123, M01-RR00865, Department of Energy contract DE-FC03-87-ER60615, the McLoughlin Gift Fund for Cognitive Health, the Larry L. Hillblom Foundation, Fran and Ray Stark Foundation Fund for Alzheimer’s Disease Research, Ahmanson Foundation, Lovelace Foundation, the Sence Foundation, the UCLA Claude Pepper Older Americans Independence Center funded by the National Institute on Aging (5P30AG028748), AFAR, the John A. Hartford Foundation and the Centers of Excellence National Program, National Institutes of Health/National Center for Advancing Translational Science (NCATS) University of California Los Angeles Center for Translational Science Investigation Grant Number UL1TR000124. These agencies were not involved in the approval and review of the manuscript nor in the decision to submit the manuscript for publication. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health or other funding agencies.
Publisher Copyright:
© 2018 Siddarth et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
PY - 2018/4
Y1 - 2018/4
N2 - Atrophy of the medial temporal lobe (MTL) occurs with aging, resulting in impaired episodic memory. Aerobic fitness is positively correlated with total hippocampal volume, a heavily studied memory-critical region within the MTL. However, research on associations between sedentary behavior and MTL subregion integrity is limited. Here we explore associations between thickness of the MTL and its subregions (namely CA1, CA23DG, fusiform gyrus, subiculum, parahippocampal, perirhinal and entorhinal cortex,), physical activity, and sedentary behavior. We assessed 35 non-demented middle-aged and older adults (25 women, 10 men; 45–75 years) using the International Physical Activity Questionnaire for older adults, which quantifies physical activity levels in MET-equivalent units and asks about the average number of hours spent sitting per day. All participants had high resolution MRI scans performed on a Siemens Allegra 3T MRI scanner, which allows for detailed investigation of the MTL. Controlling for age, total MTL thickness correlated inversely with hours of sitting/day (r = -0.37, p = 0.03). In MTL subregion analysis, parahippocampal (r = -0.45, p = 0.007), entorhinal (r = -0.33, p = 0.05) cortical and subiculum (r = -0.36, p = .04) thicknesses correlated inversely with hours of sitting/day. No significant correlations were observed between physical activity levels and MTL thickness. Though preliminary, our results suggest that more sedentary non-demented individuals have less MTL thickness. Future studies should include longitudinal analyses and explore mechanisms, as well as the efficacy of decreasing sedentary behaviors to reverse this association.
AB - Atrophy of the medial temporal lobe (MTL) occurs with aging, resulting in impaired episodic memory. Aerobic fitness is positively correlated with total hippocampal volume, a heavily studied memory-critical region within the MTL. However, research on associations between sedentary behavior and MTL subregion integrity is limited. Here we explore associations between thickness of the MTL and its subregions (namely CA1, CA23DG, fusiform gyrus, subiculum, parahippocampal, perirhinal and entorhinal cortex,), physical activity, and sedentary behavior. We assessed 35 non-demented middle-aged and older adults (25 women, 10 men; 45–75 years) using the International Physical Activity Questionnaire for older adults, which quantifies physical activity levels in MET-equivalent units and asks about the average number of hours spent sitting per day. All participants had high resolution MRI scans performed on a Siemens Allegra 3T MRI scanner, which allows for detailed investigation of the MTL. Controlling for age, total MTL thickness correlated inversely with hours of sitting/day (r = -0.37, p = 0.03). In MTL subregion analysis, parahippocampal (r = -0.45, p = 0.007), entorhinal (r = -0.33, p = 0.05) cortical and subiculum (r = -0.36, p = .04) thicknesses correlated inversely with hours of sitting/day. No significant correlations were observed between physical activity levels and MTL thickness. Though preliminary, our results suggest that more sedentary non-demented individuals have less MTL thickness. Future studies should include longitudinal analyses and explore mechanisms, as well as the efficacy of decreasing sedentary behaviors to reverse this association.
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U2 - 10.1371/journal.pone.0195549
DO - 10.1371/journal.pone.0195549
M3 - Article
C2 - 29649304
AN - SCOPUS:85045477575
VL - 13
JO - PLoS ONE
JF - PLoS ONE
SN - 1932-6203
IS - 4
M1 - e0195549
ER -