Impaired mobility and MRI markers of vascular brain injury: Atherosclerosis Risk in Communities and UK Biobank studies.

Background: Vascular brain injury (VBI) may be an under-recognised contributor to mobility impairment. We examined associations between MRI VBI biomarkers and impaired mobility.
Methods: We separately analysed Atherosclerosis Risk in Communities (ARIC) and UK Biobank (UKB) study cohorts. Inclusion criteria were no prevalent clinical stroke, and available brain MRI and balance and gait data. MRI VBI biomarkers were (ARIC: ventricular and white matter hyperintensity (WMH) volumes, non-lacunar and lacunar infarctions, microhaemorrhage; UKB: ventricular, brain and WMH volumes, fractional anisotropy (FA), mean diffusivity (MD), intracellular and isotropic free water volume fractions). Quantitative biomarkers were categorised into tertiles. Mobility impairment outcomes were imbalance and slow walk in ARIC and recent fall and slow walk in UKB. Adjusted multivariable logistic regression analyses were performed.
Results: We included 1626 ARIC (mean age 76.2 years; 23.4% imbalance, 25.0% slow walk) and 40 098 UKB (mean age 55 years; 15.8% falls, 2.8% slow walk) participants. In ARIC, imbalance associated with four of five VBI measures (all p values<0.05), most strongly with WMH (adjusted OR, aOR 1.64; 95% CI 1.18 to 2.29). Slow walk associated with four of five VBI measures, most strongly with WMH (aOR 2.32; 95% CI 1.66 to 3.24). In UKB, falls associated with all VBI measures except WMH, most strongly with FA (aOR 1.16; 95% CI 1.08 to 1.24). Slow walking associated with WMH, FA and MD, most strongly with FA (aOR 1.57; 95% CI 1.32 to 1.87).
Conclusions: VBI is associated with mobility impairment in community-dwelling, clinically stroke-free cohorts. Consequences of VBI may extend beyond clinically apparent stroke to include mobility.
Competing Interests: Competing interests: RS reports grants from NIH Clinical Centre. AdH has received investigator-initiated clinical research funding from Regeneron, AMGEN and AMAG pharmaceuticals, and has equity in TitinKM and Certus. HK reports receiving personal fees from UnitedHealth, Element Science, Aetna, Reality Labs, F-Prime, Tesseract/4Catalyst, Martin/Baughman Law Firm, Arnold and Porter Law Firm, and Siegfried and Jensen Law Firm; being a cofounder of HugoHealth, a personal health information platform; being a cofounder of Refractor Health, an Enterprise Health Care artificial intelligence-augmented data management company; having contracts with the Centers for Medicare & Medicaid Services Association through Yale New Haven Hospital, to develop and maintain performance measures that are publicly reported; and receiving grants from Johnson & Johnson outside the submitted work. GJF reports grants from the Neurocritical Care Society Research Fellowship. KNS reports compensation from CSL Behring for consultant services; compensation from Sense for data and safety monitoring services; compensation from Cerevasc for consultant services; compensation from Rhaeos for consultant services; compensation from Certus for consultant services; service as President for Advanced Innovation in Medicine; a patent pending for Stroke wearables licensed to Alva Health. The other authors report no conflicts.
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