Olfactory identification deficits and increased mortality in the community.

OBJECTIVE

To examine the association between odor identification deficits and future mortality in a multiethnic community cohort of older adults.

METHODS

Participants were evaluated with the 40-item University of Pennsylvania Smell Identification Test (UPSIT). Follow-up occurred at 2-year intervals with information on death obtained from informant interviews and the National Death Index.

RESULTS

During follow-up (mean = 4.1 years, standard deviation = 2.6), 349 of 1,169 (29.9%) participants died. Participants who died were more likely to be older (p < 0.001), be male (p < 0.001), have lower UPSIT scores (p < 0.001), and have a diagnosis of dementia (p < 0.001). In a Cox model, the association between lower UPSIT score and mortality (hazard ratio [HR] = 1.07 per point interval, 95% confidence interval [CI] = 1.05-1.08, p < 0.001) persisted after controlling for age, gender, education, ethnicity, language, modified Charlson medical comorbidity index, dementia, depression, alcohol abuse, head injury, smoking, body mass index, and vision and hearing impairment (HR = 1.05, 95% CI = 1.03-1.07, p < 0.001). Compared to the fourth quartile with the highest UPSIT scores, HRs for mortality for the first, second, and third quartiles of UPSIT scores were 3.81 (95% CI = 2.71-5.34), 1.75 (95% CI = 1.23-2.50), and 1.58 (95% CI = 1.09-2.30), respectively. Participant mortality rate was 45% in the lowest quartile of UPSIT scores (anosmia) and 18% in the highest quartile of UPSIT scores.

INTERPRETATION: Impaired odor identification, particularly in the anosmic range, is associated with increased mortality in older adults even after controlling for dementia and medical comorbidity.