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

Kazuko Mitoku, Naoko Masaki, Yukiko Ogata, Kazushi Okamoto

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. 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. 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. Cognitive impairment was most common in individuals with dual sensory impairment, and those with dual sensory impairment and cognitive impairment had increased mortality.