Vision and hearing impairments, cognitive impairment and mortality among long-term care recipients: a population- based cohort study

Background: Vision and hearing impairments among elders are common, and cognitive impairment is a concern. This study assessed the association of vision and hearing impairments with cognitive impairment and mortality among long-term care recipients. Methods: Data of 1754 adults aged 65 or older were included in analysis from the Gujo City Long-Term Care Insurance Database in Japan for a mean follow-up period of 4.7 years. Trained and certified investigators assessed sensory impairments and cognitive impairment using a national assessment tool. Five-level scales were used to measure vision and hearing impairments. Cognitive performance was assessed on two dimensions, namely communication/ cognition and problem behaviors. We performed logistic regression analysis to estimate odd ratios (ORs) and 95 % confidence intervals (CIs) for the association of vision and hearing impairments with cognitive impairment. Using Cox proportional hazard regression models, we obtained hazard ratios (HRs) for mortality. Results: Of 1754 elders, 773 (44.0 %) had normal sensory function, 252 (14.4 %) vision impairment, 409 (23.3 %) hearing impairment, and 320 (18.2 %) dual sensory impairment. After adjusting for potential cofounders, ORs of cognitive impairment were 1.46 (95 % CI 1.07-1.98) in individuals with vision impairment, 1.47 (95 % CI 1.13-1.92) in those with hearing impairment, and 1.97 (95 % CI 1.46-2.65) in those with dual sensory impairment compared to individuals with normal sensory function. The adjusted HR of overall mortality was 1.29 (95 % CI 1.01-1.65) in individuals with dual sensory impairment and cognitive impairment relative to normal sensory and cognitive functions. Conclusions: Cognitive impairment was most common in individuals with dual sensory impairment, and those with dual sensory impairment and cognitive impairment had increased mortality.