Bone tissue is innervated, and peripheral nerve function may impact BMD. Older black and white men and women (N = 2200) in the Health, Aging, and Body Composition Study with worse sensory and motor peripheral nerve function had lower hip BMD and calcaneal BUA independent of lean mass, strength, physical ability, and diabetes. Poor peripheral nerve function may directly affect bone.
Introduction: Bone tissue is innervated, yet little is known about the impact of nerve function on BMD. Poor peripheral nerve function may contribute to lower BMD and higher fracture risk, particularly in those with diabetic neuropathy.
Materials and methods: The Health, Aging, and Body Composition (Health ABC) Study included annual exams in white and black men and women 70-79 years of age recruited from Pittsburgh and Memphis. Nerve function in legs/feet was assessed by 1.4- and 10-g monofilament detection, vibration threshold, and peroneal motor nerve conduction velocity (NCV) and amplitude (CMAP). Total hip BMD, heel broadband ultrasound attenuation (BUA), and total fat and lean mass were measured 1 year later (QDR 4500A, Sahara QUS; Hologic).
Results: Participants (N = 2200) were 48% men and 37% black. Poor nerve function (lower monofilament detection, higher vibration threshold, lower CMAP, lower NCV) was associated with 1.4-5.7% lower BUA and significant for all but NCV, adjusted for demographics, diabetes, body composition, and physical ability. Results were similar for adjusted hip BMD, with 1.0-2.9% lower BMD, significant for monofilament and CMAP testing. When considering the components of BMD, total hip area was 1.8-4.9% higher in those with the worst nerve function, although BMC showed little difference. Lower monofilament detection and CMAP were independently associated with lower heel BUA (p < 0.01), and monofilament detection was associated with lower hip BMD (p < 0.05) in regression additionally adjusted for lifestyle factors, bone-active medications, and diabetes-related complications.
Conclusions: Poor peripheral nerve function may directly related to lower BMD, likely through an increase in bone area in older adults, independent of lean mass, strength, physical ability, and diabetes. Whether those with impaired nerve function are at higher risk for fracture independent of falls needs to be studied.