Sensory impairments and the risk of cognitive decline and dementia across sex, age, and regions: Longitudinal insights from Europe

Abstract

Background: In aging populations, understanding predictors of cognitive decline is essential. We aimed to investigate the risk of cognitive decline and dementia by sensory impairments across sex, age, and European regions, and examined the mediating role of activities of daily living (ADL), physical activity, and depressive symptoms.

Methods: A cohort study of 72,287 Europeans aged 50+ participating in at least two waves of the Survey of Health, Ageing and Retirement in Europe. We employed mixed-effects and time-to-event models, incorporating sex interactions, and adjusting for socio-demographic factors and medical history.

Results: Compared to individuals with good vision and hearing, lower cognitive function was found for people with vision impairment (VI) (males: coef. -0.70, 95 % CI -0.95; -0.46; females: coef. -1.12, 95 % CI -1.33; -0.92), hearing impairment (HI) (males: coef. -0.64, 95 % CI -0.93; -0.35; females: coef. -0.96, 95 % CI -1.27; -0.65) and dual sensory impairment (DSI, i.e. VI and HI) (males: coef. -1.81, 95 % CI -2.16; -1.46; females: coef. -2.71, 95 % CI -3.05; -2.38), particularly among females. Moreover, higher dementia risk was observed among participants with VI (hazard ratio (HR) 1.29, 95 % CI 1.17; 1.43), HI (HR 1.18, 95 % CI 1.05; 1.34), and DSI (HR 1.62, 95 % CI 1.45; 1.81) with no sex-interactions. Findings were overall consistent across age and European regions.

Conclusion: The results suggest the necessity of preventing sensory impairments to maintain good cognitive function. Mitigating depressive symptoms, ADL limitations, and physical inactivity could potentially reduce a significant portion of the total effect of sensory impairments on cognitive decline.

Keywords: Cognitive function; Dementia; Dual sensory impairment; Hearing; Mediation; Vision.