Could the Loss of Smell Predict Future Mortality?
In a recent study, researchers found an association between the loss of smell and an increased likelihood of future mortality in older adults.
The decade long prospective cohort study included 1774 Swedish participants between 40 and 90 years of age without dementia at baseline. Olfactory function was self-reported by participants, and researchers used the Scandinavian Odor Identification Test (SOIT) to assess olfactory performance. In addition, several social, cognitive, and medical risk factors at baseline were measured and incidence of dementia was documented.
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A total of 411 participants (23.2%) died during the 10-year follow-up.
The researchers’ findings showed a significant association between higher SOIT scores and lower mortality (hazard ratio [HR] 0.74 per point interval, 95% confidence interval [CI] 0.71–0.77, P<.001). After controlling for age, sex, education, and health-related cognitive variables, the effect was attenuated but remained significant (HR 0.92, 95% CI 0.87–0.97, P = .001). In addition, the association between SOIT scores and mortality remained significant after researchers controlled for incidence of dementia before death (HR 0.92, 95% CI 0.87–0.97, P = .001). Results based upon patients’ self-reported olfactory dysfunction were similar.
“Poor odor identification and poor self-reported olfactory function are associated with greater likelihood of future mortality. Dementia does not attenuate the association between olfactory loss and mortality, suggesting that olfactory loss might mark deteriorating health, irrespective of dementia,” the researchers concluded.
—Melissa Weiss
Reference:
Ekström I, Sjölund S, Nordin S, et al. Smell Loss Predicts Mortality Risk Regardless of Dementia Conversion [published online March 22, 2017]. J Am Geriatr Soc. doi:10.1111/jgs.14770.