Objectives: To determine whether sensory and motor nerve function is associated cross-sectionally with quadriceps or ankle dorsiflexion strength in an older community-based population.
Design: Cross-sectional analyses within a longitudinal cohort study.
Setting: Two U.S. clinical sites.
Participants: Two thousand fifty-nine Health, Aging and Body Composition Study (Health ABC) participants (49.5% male, 36.7% black, aged 73-82) in 2000/01.
Measurements: Quadriceps and ankle strength were measured using an isokinetic dynamometer. Sensory and motor peripheral nerve function in the legs and feet was assessed using 10-g and 1.4-g monofilaments, vibration threshold, and peroneal motor nerve conduction amplitude and velocity.
Results: Monofilament insensitivity, poorest vibration threshold quartile (>60 mu), and poorest motor nerve conduction amplitude quartile (<1.7 mV) were associated with 11%, 7%, and 8% lower quadriceps strength (all P<.01), respectively, than in the best peripheral nerve function categories in adjusted linear regression models. Monofilament insensitivity and lowest amplitude quartile were both associated with 17% lower ankle strength (P<.01). Multivariate analyses were adjusted for demographic characteristics, diabetes mellitus, body composition, lifestyle factors, and chronic health conditions and included all peripheral nerve measures in the same model. Monofilament insensitivity (beta=-7.19), vibration threshold (beta=-0.097), and motor nerve conduction amplitude (beta=2.01) each contributed independently to lower quadriceps strength (all P<.01). Monofilament insensitivity (beta=-5.29) and amplitude (beta=1.17) each contributed independently to lower ankle strength (all P<.01). Neither diabetes mellitus status nor lean mass explained the associations between peripheral nerve function and strength.
Conclusion: Reduced sensory and motor peripheral nerve function is related to poorer lower extremity strength in older adults, suggesting a mechanism for the relationship with lower extremity disability.