Abstract

BACKGROUND:

Few studies have examined impairment in multiple senses (multisensory impairment) and risk of dementia in comparison to having a single or no sensory impairment.

METHODS:

We studied 1,810 black and white non-demented participants from Health, Aging, and Body Composition (Health ABC) Study aged 70-79 at enrollment. Sensory impairment was determined at our study baseline (Year 3-5 of Health ABC) using established cut-points for vision (Bailey-Lovie visual acuity and Pelli-Robson contrast sensitivity test), hearing (audiometric testing), smell (12-item Cross-Cultural Smell Identification Test), and touch (peripheral nerve function tests). Incident dementia over 10 years of follow-up was based on hospitalization records, dementia medications, or ≥1.5 Standard Deviation decline in Modified Mini-Mental State Exam score (race-specific). Cox proportional hazard models with adjustment for demographics, health behaviors, and health conditions evaluated the relationship between risk of dementia and increasing number of sensory impairments.

RESULTS:

Sensory impairments were common: 28% had visual impairment, 35% had hearing loss, 22% had poor smell, 12% had touch insensitivity; 26% had 2+ impairments, and 5.6% had 3+ sensory impairments. Number of impairments was associated with risk of dementia in a graded fashion (p<0.001). Compared to no sensory impairments, the adjusted Hazard Ratio (HR) was 1.5 (95%CI:1.1,2.0) for 1 sensory impairment, 1.9 (95%CI:1.4,2.6) for 2 sensory impairments, and 2.8 (95%CI:1.9,4.3) for 3+ sensory impairments.

CONCLUSIONS:

Multisensory impairment was strongly associated with increased risk of dementia. Although, the nature of this relationship needs further investigation, sensory function assessment in multiple domains may help identify patients at high risk of dementia.