Temporal associations between treated and untreated hearing loss and mild behavioral impairment in older adults without dementia

INTRODUCTION: Hearing loss (HL) and mild behavioral impairment (MBI) are non‐cognitive markers of dementia. This study investigated the relationship between hearing and MBI and explored the influence of hearing aid use on the treatment of hearing loss, both cross‐sectionally and longitudinally. METHODS: Data were analyzed from National Alzheimer's Coordinating Center participants, age ≥50, dementia‐free at baseline, collected between 2005 and 2022. Three self‐report questions were used to generate a three‐level categorical hearing variable: No‐HL, Untreated‐HL, and Treated‐HL. MBI status was derived from the informant‐rated Neuropsychiatric Inventory Questionnaire (NPI‐Q) using a published algorithm. At baseline (n = 7080), logistic regression was used to examine the association between hearing status (predictor) and the presence of global and domain‐specific MBI (outcome), adjusting for age, sex, cognitive diagnosis, and apolipoprotein E4 (APOE4). Cox proportional hazard models with time‐dependent covariates were used to examine the effect of (1) hearing status as exposure on the rate of incident MBI (n = 5889); and (2) MBI as exposure on the rate of incident HL in those with no HL at baseline (n = 6252). RESULTS: Cross‐sectionally, participants with Untreated‐HL were more likely to exhibit global MBI (adjusted odds ratio (aOR) = 1.66, 95% CI: 1.24–2.21) and individual MBI domains of social inappropriateness (aOR = 1.95, 95% CI: 1.06–3.39), affective dysregulation (aOR = 1.71, 95% CI: 1.21–2.38), and impulse dyscontrol (aOR = 1.71, 95% CI: 1.21–2.38), compared to those with No‐HL. Participants with Treated‐HL (i.e., hearing aid use) did not differ from No‐HL for odds of global or most MBI domains, except for impulse dyscontrol (aOR = 1.38, 95% CI: 1.05–1.81). Longitudinally, we found relationships between Treated‐HL and incident MBI (adjusted hazard ratio (aHR) = 1.29, 95% CI: 1.01–1.63) and between MBI and incident Untreated‐HL (aHR = 1.51, 95% CI: 1.19–1.94). DISCUSSION: Our cross‐sectional results support that hearing aid use is associated with lower odds of concurrent global MBI in dementia‐free participants. Longitudinally, relationships were found between MBI and HL. The severity of HL was not assessed, however, and may require further exploration. HIGHLIGHTS: Hearing Loss (HL) and mild behavioral impairment (MBI) are markers of dementia. Cross‐sectionally: Untreated‐HL was associated with global MBI burden, but HL treated with hearing aids was not. We found associations between MBI and incident Untreated‐HL;