Trajectories of cognitive decline before and after new‐onset dual sensory impairment: findings from two longitudinal studies

INTRODUCTION: The trajectories of cognitive decline before and after new-onset dual sensory impairment (DSI) remain largely unknown. METHODS: Participants were included without DSI at baseline and with at least two recorded cognitive measures. A linear mixed-effects model was used to analyze the trend of cognitive function changes over time before and after DSI. RESULTS: The annual rate of cognitive decline was similar at baseline between individuals who experienced DSI onset and individuals with non-DSI. After the DSI onset, the slope of global cognitive decline in the DSI group was statistically different from that in the non-DSI group (in the China Health and Retirement Longitudinal Study, β: -0.098 standard deviation [SD]/year; 95% confidence interval [CI]: -0.145 to -0.050. In the English Longitudinal Study of Ageing, β: -0.085 SD/year; 95% CI: -0.165 to -0.006). DISCUSSION: Participants experienced accelerated cognitive decline upon developing new-onset DSI. Incident DSI is associated with accelerated cognitive decline after, but not before, the event.