Associations Between Inflammation and Multisensory Impairment Among Older Adults.

Background: Impairment in multiple senses (multisensory impairment) is common in older adults but the underlying mechanisms are unclear. We evaluated whether common blood-based markers of inflammation (e.g., Interleukin 6 (IL-6), C-Reactive Protein (CRP), and Tumor Necrosis Factor Alpha (TNF-α)) were associated with multisensory impairment.

Methods: We analyzed data from 1674 participants in the Health, Aging, and Body Composition Study, a prospective cohort study of Black and White older adults who were aged 70-79 at enrollment. IL-6, CRP, and TNF-α were assayed from blood samples at Year 1. Sensory function in 4 domains was assessed in Years 3-5; impairment was defined with clinical cut-points. Vision was measured by visual acuity and contrast sensitivity; hearing by pure tone audiometry (500, 1000, 2000, and 4000 Hz); smell by the 12-item Cross Cultural Smell Identification Test; and touch by vibration detection threshold and monofilament of the big toe. A previously developed multisensory impairment score (0-12) was calculated based on sample quartiles and summed across sensory domains. Regression models evaluated the associations of inflammation markers with individual and multiple sensory impairments (as separate outcomes) with adjustment for demographics, health conditions, and health behaviors.

Results: Higher CRP (ß = 0.07; 95% CI: 0.01-0.12; p = 0.01) and IL-6 (ß = 0.11; 95% CI: 0.04-0.18; p = 0.003) levels were associated with the number of sensory impairments. Participants with the highest quartile of IL-6 (OR = 1.45; 95% CI: 1.09-1.92; p = 0.01) and TNF-α (OR = 1.46; 95% CI: 1.12-1.91; p = 0.005) had higher odds of a poor multisensory impairment score. High CRP was associated with impaired vision (OR = 1.45; 95% CI:1.08-1.93; p = 0.01) and high TNF-α was associated with touch impairment (OR = 1.63; 95% CI:1.15-2.30; p = 0.006). Having multiple high markers was also associated with multisensory (OR: 1.76; 95% CI: 1.20-2.58; p = 0.004) and vision impairment (OR: 1.55; 95% CI: 1.13-2.13; p = 0.004).

Conclusions: Markers of inflammation were associated with multisensory impairment, but there were fewer associations with individual sensory impairments.