米国メディケア受益者における感覚運動障害と新規認知症

Sensorimotor impairments, including sensory (vision and hearing) and motor (standing balance, gait, chair stands, grip strength) deficits, are prevalent in older adults and are associated with an increased risk of dementia. Understanding the individual and combined effects of these impairments on dementia risk may enhance early detection and preventive strategies. We examined the association between baseline sensory difficulties and motor impairments, individually and collectively, with dementia over up to 11 years.

We used data from the National Health and Aging Trends Study (NHATS), a nationally representative study of US community-dwelling Medicare beneficiaries aged ≥ 65 years. Participants cognitively unimpaired at baseline in 2011 were followed annually through 2022. Baseline exposures included self-reported sensory difficulties (vision, hearing) and objectively measured motor impairments (standing balance, gait speed, chair stand, grip strength). The primary outcome was incident dementia, assessed annually based on NHATS consensus procedures. Survey-weighted Cox proportional hazards models assessed the association between each impairment and number of impairments and incident dementia, adjusting for demographics and clinical conditions.

The analytic sample included 3847 participants (weighted average age 73.9 (95% CI, 73.7-74.1) years, 56% women). Over an average follow-up of 5.2 years, vision difficulty (HR = 1.34; 95% CI, 1.13-1.60), standing balance impairment (HR = 1.23; 95% CI, 1.10-1.39), slow gait speed (HR = 1.49; 95% CI, 1.34-1.67), impaired chair stand performance (HR = 1.31; 95% CI, 1.18-1.47), and weak grip strength (HR = 1.31; 95% CI, 1.13-1.51) were each independently associated with higher dementia risk. Compared to no impairments, dementia risk increased significantly with three or more sensorimotor impairments (HR = 1.44 to 1.96).

In this nationally representative cohort, vision difficulty and motor impairments were independently associated with increased dementia risk over up to 11 years. The presence of multiple sensory difficulties and motor impairments substantially increased the risk of dementia, emphasizing the importance of their early detection and management to reduce dementia risk.