Grip Strength, Gait Speed and Plasma Markers of Neurodegeneration in Asymptomatic Middle-aged and Older Adults.

BACKGROUND

Pragmatic biomarkers of preclinical dementia would allow for easy and large-scale screening of risk in populations. Physical function measures like grip strength and gait speed are potential predictive biomarkers but their relationship with plasma markers of Alzheimer's Disease and neurodegeneration have not been elucidated.

OBJECTIVES

To examine association between physical function measures and plasma markers of Alzheimer's Disease (AD) and neurodegeneration.

DESIGN

Cross-sectional and longitudinal analyses.

SETTING

Community-based cohort in the city of Framingham, Massachusetts.

PARTICIPANTS

2336 participants of the Framingham Heart Study Offspring cohort with an average age of 61.

MEASUREMENTS

Plasma Aβ40 and Aβ42 were measured in 1998-2001 (Exam-7) and plasma total tau measured 5 years later (Exam-8). Grip strength, fast walk speed and chair stand speed were measured at both exams. Quantification of Aβ isoforms in plasma was performed using INNO-BIA assays and plasma total-tau was measured using Quanterix Simoa HD-1 assay. Confounder-adjusted linear regression models examined associations between physical function and plasma markers, Results: Grip strength at Exam-7 was associated with plasma Aβ40 (β -0.006, p-value 0.032) at Exam-7 and plasma total-tau (β -0.010, p-value 0.001) at Exam-8. Grip strength and fast walk speed at Exam-8 were associated with plasma total-tau at Exam-8 (GS: β -0.009, p 0.0005; FWS: β -0.226, p-value <0.0001). Chair stand speed was not associated with plasma markers; Aβ42 was not associated with function.

CONCLUSION

Grip strength and fast walk speed are associated with plasma markers of neurodegeneration in dementia-free middle aged and older individuals. Both these measures could be used as potential screening tools for identifying individuals at a higher risk for AD and related dementias alongside other validated markers.