Worse Sensorimotor Peripheral Nerve Function is Associated with Lower Objective Physical Activity in Older Men

Abstract

Sensorimotor peripheral nerve (PN) impairments are common in older adults and negatively impact mobility and lower extremity physical function. Whether worse PN is related to lower physical activity levels (PA) is unclear, though PA may be in the pathway from PN to mobility disability. PURPOSE: To determine whether worse PN function is associated with lower PA levels in older men. METHODS: In 2007–09, participants at the Pittsburgh, PA, site of the Osteoporotic Fractures in Men Study (age 78.9 ± 4.7 years) underwent sural sensory nerve (SNAP=amplitude in uV) and peroneal motor nerve (CMAP=amplitude in mV) conduction testing using a neurodiagnostic instrument. CMAP and SNAP were categorized into tertiles, with lower tertiles indicating worse PN function. Objective PA was assessed using a multisensor armband. Multivariate linear regression modeled the association between PN and minutes per day of sedentary (<1.6 METS, excluding sleep), light (1.6 to <3.0 METS), moderate (3.0 to <6.0 METS) and vigorous (6.0+ METS) activity, adjusting for demographic, lifestyle, and health factors. Proprietary algorithms estimated METS using age, smoking, and body mass index, so they were not included in the primary models, though age-adjusted sensitivity analyses were done. RESULTS: Participants (n=307) spent a median of 832, 64, 70, and 9 minutes in sedentary, light, moderate, and vigorous activity per day, respectively. After adjusting for health status and diabetes, men in the lowest tertile of CMAP participated in 16%, 17%, and 32% fewer minutes of light, moderate and vigorous activity and 4% more sedentary time compared to the middle/highest tertile (p<0.05 for all). Compared to the middle/highest tertile, men with the lowest SNAP participated in 16%, 20%, and 28% fewer minutes of light, moderate and vigorous activity, respectively (p<0.05 for all), though sedentary time did not differ. Further adjustment for age slightly attenuated associations between PN and PA, with relationships to moderate PA becoming non-significant. CONCLUSION: Worse PN is associated with less daily PA in older men, indicating a potential pathway for disability that warrants further investigation. Supported by NIH: U01 AR45580, U01 AR45614, U01 AR45632, U01 AR45647, U01 AR45654, U01 AR45583, U01 AG18197, U01 AG027810, UL1 TR000128 and T32-AG000181.