Identifying mechanisms that compensate for slow gait speed in older adults is crucial. Dopaminergic neurotransmission curbs deleterious associations of cerebrovascular disease with gait, but whether it compensates for peripheral systemic risk factors (PSRF) for gait slowing has not been studied. In this cross-sectional study of community-dwelling older adults, we examined the relationship between nigrostriatal dopaminergic terminal integrity and gait speed in individuals with and without ≥1 PSRF for gait slowing: obesity, joint pain, or reduced muscle strength. The primary outcome was percent difference in gait speed (%DGS) on transition from even to uneven surface. Participants underwent dopaminergic imaging with dihydrotetrabenazine [11C]DTBZ positron emission tomography. Among 197 individuals, (mean (SD) age 74.92 (4.53) years; 61.93% female; 90.86% White), 130 (65.99%) had ≥1 PSRF. Relationship between posterior putamen [11C]DTBZ binding and %DGS was modified by PSRF; in those with ≥1 PSRF (but not in those with no PSRF), posterior putamen [11C]DTBZ binding was associated with %DGS (β=0.198, p=0.03) independent of potential confounders. This cross-sectional study indicates that striatal dopaminergic neurotransmission may offer resilience to effects of PSRF on gait slowing.

The authors have declared no competing interest.

This work was supported by the National Institutes of Health grant U01AG061393 and 5R01AG075025. The Monongahela-Youghiogheny Healthy Aging Team (MYHAT) is funded by NIH R37 AG 023651.The Study of Muscle, Mobility and Aging is supported by funding from the National Institute on Aging, grant number AG059416. Study infrastructure support was funded in part by NIA Claude D. Pepper Older American Independence Centers at University of Pittsburgh (P30AG024827) and Wake Forest University (P30AG021332) and the Clinical and Translational Science Institutes, funded by the National Center for Advancing Translational Science, at Wake Forest University (UL1 0TR001420).

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