Olfactory identification deficits and increased mortality in the community

ObjectiveTo examine the association between odor identification deficits and future mortality in a multiethnic community cohort of older adults. MethodsParticipants 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. ResultsDuring 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. InterpretationImpaired odor identification, particularly in the anosmic range, is associated with increased mortality in older adults even after controlling for dementia and medical comorbidity. Ann Neurol 2015;78:401-411