Poor odor identification predicts mortality risk in older adults without neurodegenerative diseases: the Shanghai Aging Study

Abstract

BackgroundIrrespective of neurodegeneration, the decline of olfactory function might also reflect a wider range of pathological conditions contributing to mortality. However, the potential explanations and their predictive values have rarely been reported.MethodsA total of 1,433 older adults aged ≥ 60 years without neurodegenerative disease were administered a follow-up of 8.6 years on average. Sniffin’ Sticks Screening Test was used to assess the olfactory identification at baseline. Survival status during the follow-up was obtained from the local Center for Disease Control and Prevention. Bidirectional stepwise Cox proportional hazards regression was used to identify variables associated with mortality. Two predictive models were constructed by statistical learning methods.ResultsAll-cause mortality rate was 1.1/100 person-years during the follow-up. Sex (HR = 0.65, 95%CI 0.46 - 0.93), age (HR = 1.12, 95%CI 1.10 - 1.15), chronic kidney disease (HR = 1.88, 95%CI 1.09 - 3.25), low density lipoprotein (HR = 0.81, 95%CI 0.67 - 0.99), anemia (HR = 2.74, 95%CI 1.19 - 6.30), and fail to identify coffee odor (HR = 1.96, 95%CI 1.19 - 3.23) were significantly associated with all-cause mortality. The logistic regression and the random forest predictive models showed similar predictive accuracy (0.91 and 0.90) and area under the receiver operating characteristic curve (0.77 and 0.75).ConclusionsThe association between poor olfactory and long-term mortality was verified among Chinese older population. Certain odors identification ability may contribute to the prediction of long-term mortality along with other important risk factors.