Obesity is associated with reduced cerebral blood flow – modified by physical activity

Silvin P. Knight*, Eamon Laird, Wilby Williamson, John O'Connor, Louise Newman, Daniel Carey, Celine De Looze, Andrew J. Fagan, Michael A. Chappell, James F. Meaney, Rose Anne Kenny

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

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This study examined the associations of body mass index (BMI), waist-to-hip ratio (WHR), waist circumference (WC), and physical activity (PA) with gray matter cerebral blood flow (CBFGM) in older adults. Cross-sectional data was used from the Irish Longitudinal Study on Ageing (n = 495, age 69.0 ±7.4 years, 52.1% female). Whole-brain CBFGM was quantified using arterial spin labeling MRI. Results from multivariable regression analysis revealed that an increase in BMI of 0.43 kg/m2, WHR of 0.01, or WC of 1.3 cm were associated with the same reduction in CBFGM as 1 year of advancing age. Participants overweight by BMI or with high WHR/WC reporting low/moderate PA had up to 3 ml/100g/min lower CBFGM (p ≤.011); there was no significant reduction for those reporting high PA. Since PA could potentially moderate obesity/CBF associations, this may be a cost-effective and relatively easy way to help mitigate the negative impact of obesity in an older population, such as cerebral hypoperfusion, which is an early mechanism in vascular dementia and Alzheimer's disease.

Original languageEnglish
Pages (from-to)35-47
Number of pages13
JournalNeurobiology of Aging
Early online date22 Apr 2021
Publication statusPublished - Sep 2021
Externally publishedYes

Bibliographical note

Funding Information:
The authors would like to acknowledge the continued commitment and cooperation of the TILDA participants and research team. MRI data collection was supported by the National Centre for Advanced Medical Imaging (CAMI); the authors would particularly like to acknowledge Jason McMorrow and Caoilfhionn Ni Leidhin for their assistance with MRI data processing. This research was funded by the Health Research Board (HRB) [HRA-PHR-2014-667]. TILDA is funded by The Irish Government, The Atlantic Philanthropies and Irish Life PLC . Funders played no role in the design, execution, analysis, interpretation of data or writing of this research. The National Centre for Advanced Medical Imaging (CAMI) is grant-funded by the HRB . One of the authors (SPK) acknowledges funding from Science Foundation Ireland (SFI) [18/FRL/6188]. One of the authors (MC) acknowledges funding from the Engineering and Physical Sciences Research Council UK [EP/P012361/1]. The Wellcome Centre for Integrative Neuroimaging is supported by core funding from the Wellcome Trust [203139/Z/16/Z].

Publisher Copyright:
© 2021 The Author(s)

Copyright 2021 Elsevier B.V., All rights reserved.


  • Arterial spin labeling MRI
  • Cerebral blood flow
  • Cerebral perfusion
  • Obesity
  • Physical activity

ASJC Scopus subject areas

  • Neuroscience(all)
  • Ageing
  • Developmental Biology
  • Clinical Neurology
  • Geriatrics and Gerontology


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