Peripheral nerve function and lower extremity muscle power in older men.

ABSTRACT

OBJECTIVE: To assess whether sensorimotor peripheral nerve function is associated with muscle power in community-dwelling older men. DESIGN: Longitudinal cohort study with 2.3±0.3 years of follow-up. SETTING: One clinical site. PARTICIPANTS: Participants (n=372; mean age ± SD, 77.2±5.1y; 99.5% white; body mass index, 27.9±3.7kg/m(2); power, 1.88±0.6W/kg) at 1 site of the Osteoporotic Fractures in Men Study (N=5994). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: A nerve function ancillary study was performed 4.6±0.4 years after baseline. Muscle power was measured using a power rig. Peroneal motor nerve conduction amplitude, distal motor latency, and mean f-wave latency were measured. Sensory nerve function was assessed using 10-g and 1.4-g monofilaments and sural sensory nerve conduction amplitude and distal latency. Peripheral neuropathy symptoms at the leg and feet were assessed by self-report. RESULTS: After adjustments for age, height, and total body lean and fat mass, 1 SD lower motor (ß=-.07, P<.05) and sensory amplitude (ß=-.09, P<.05) and 1.4-g (ß=-.11, P<.05) and 10-g monofilament insensitivity (ß=-.17, P<.05) were associated with lower muscle power/kg. Compared with the effect of age on muscle power (ß per year, -.05; P<.001), this was equivalent to aging 1.4 years for motor amplitude, 1.8 years for sensory amplitude, 2.2 years for 1.4-g monofilament detection, and 3.4 years for 10-g detection. Baseline 1.4-g monofilament detection predicted a greater decline in muscle power/kg. Short-term change in nerve function was not associated with concurrent short-term change in muscle power/kg. CONCLUSIONS: Worse sensory and motor nerve function were associated with lower muscle power/kg and are likely important for impaired muscle function in older men. Monofilament sensitivity was associated with a greater decline in muscle power/kg, and screening may identify an early risk for muscle function decline in late life, which has implications for disability.