Longitudinal Association of Olfactory Function with Frailty in Older Adults: The Atherosclerosis Risk in Communities Study.

Background: Emerging evidence suggests that olfactory dysfunction may be a marker of frailty, a key predictor of adverse health outcomes in aging populations. This study examines the association between olfactory impairment and frailty in older adults.

Methods: We analyzed data from 5,231 participants (mean age: 75.3 ± 5.0 years; 59% women; 22% Black) of the Atherosclerosis Risk in Communities (ARIC) Study. Olfactory function, assessed using the 12-item Sniffin' Sticks Test at Visit 5 (2011-2013), was categorized as poor (0-8), moderate (9-10), or good (11-12). Frailty status was ascertained using both the Fried Frailty Phenotype and the Cumulative Frailty Index. Cross-sectional associations between olfactory function and frailty status were examined using logistic regression and linear regression. Logistic regression was used to examine the association between olfactory function and prefrailty or frailty occurring within five years among 1,519 participants robust at baseline.

Results: In cross-sectional analyses, good olfactory function was associated with lower odds of frailty (odds ratio [OR] = 0.29, 95% confidence interval [CI]: 0.22, 0.39) and prefrailty (OR = 0.52, 95% CI: 0.45, 0.61). These associations remained robust after adjusting for covariates. Longitudinal analyses similarly showed a dose-response pattern, with improved olfaction associated with decreased odds of experiencing prefrailty (OR=0.63 95% CI [0.48, 0.83]) or frailty (OR=0.50, 95% CI [0.25, 1.02]).

Conclusions: Good, as compared to poor, olfactory function is associated with lower frailty risk in older adults, suggesting that olfactory impairment may serve as an early marker of frailty. Further research is needed to elucidate the mechanisms linking olfaction and frailty and explore potential interventions.