Associations of Peripheral Neuropathy Defined by Monofilament Insensitivity with Mild Cognitive Impairment and Dementia in Older Adults

Introduction: The aim of this study was to assess the association of peripheral neuropathy (PN) as defined by monofilament insensitivity with mild cognitive impairment (MCI) and dementia in older adults with and without diabetes. Methods: We conducted a cross-sectional analysis of 3,362 Black and White participants in the Atherosclerosis Risk in Communities Neurocognitive Study (ARIC-NCS) who underwent monofilament testing at visit 6 (2016-2017, age 71-94 years). Participants' cognitive status was classified by an adjudication committee as cognitively normal, MCI, or dementia after completing a comprehensive battery of neurocognitive assessments. We used logistic regression to evaluate the association of PN with MCI or dementia overall and stratified by diabetes status after adjusting for traditional dementia risk factors. We also compared age-adjusted brain MRI measures among a subset (N = 1,095) of participants with versus without PN. Results: Overall, the prevalence of MCI (21.9% vs. 16.7%) and dementia (7.8% vs. 3.9%) were higher among participants with versus without PN (both p < 0.05). After adjustment, PN was positively associated with MCI or dementia in the overall study population (OR 1.45, 95% CI 1.23, 1.73). Results were similar by diabetes status (diabetes: OR 1.38, 95% CI 1.03-1.87; no diabetes: OR 1.48, 95% CI 1.20-1.83; p-for-interaction = 0.46). Age-adjusted total and lobar brain volumes were significantly lower in participants with versus without PN (both, p < 0.05). Discussion/Conclusions: PN as defined by monofilament insensitivity was associated with cognitive status independent of vascular risk factors and regardless of diabetes status. Our findings support a connection between PN and cognitive impairment, even in the absence of diabetes.