Prediction of mortality has focused on disease and frailty, although antecedent biomarkers may herald broad physiological decline. Olfaction, an ancestral chemical system, is a strong candidate biomarker because it is linked to diverse physiological processes. We sought to determine if olfactory dysfunction is a harbinger of 5-year mortality in the National Social Life, Health and Aging Project [NSHAP], a nationally representative sample of older U.S. adults. 3,005 community-dwelling adults aged 57–85 were studied in 2005–6 (Wave 1) and their mortality determined in 2010–11 (Wave 2). Olfactory dysfunction, determined objectively at Wave 1, was used to estimate the odds of 5-year, all cause mortality via logistic regression, controlling for demographics and health factors. Mortality for anosmic older adults was four times that of normosmic individuals while hyposmic individuals had intermediate mortality (p<0.001), a “dose-dependent” effect present across the age range. In a comprehensive model that included potential confounding factors, anosmic older adults had over three times the odds of death compared to normosmic individuals (OR, 3.37 [95%CI 2.04, 5.57]), higher than and independent of known leading causes of death, and did not result from the following mechanisms: nutrition, cognitive function, mental health, smoking and alcohol abuse or frailty. Olfactory function is thus one of the strongest predictors of 5-year mortality and may serve as a bellwether for slowed cellular regeneration or as a marker of cumulative toxic environmental exposures. This finding provides clues for pinpointing an underlying mechanism related to a fundamental component of the aging process.

African Americans are more likely to suffer from presbyosmia, a health disparity not explained by gender, education, cognition, physical or mental health, and health behaviors. This novel health disparity may result from lifetime environmental exposures, diet, or genetic susceptibility. Dissecting the interactions among these putative mechanisms will provide insight into ameliorating this decline in critical human sensory function.

Objectives Age-related decline of the five classical senses (vision, smell, hearing, touch, and taste) poses significant burdens on older adults. The co-occurrence of multiple sensory deficits in older adults is not well characterized and may reflect a common mechanism resulting in global sensory impairment. Design, Setting, and Participants The National Social Life, Health, and Aging Project, a representative, population-based study of community dwelling older US adults (57-85 years of age), collected biomarkers, social and health history, and other physiological measures, including sensory function. Measurements We estimated the frequency with which impairment co-occurred across the five senses as an integrated measure of sensory aging. We hypothesized that multisensory deficits would be common and reflect global sensory impairment which would largely explain the effects of age, gender, and race on sensory dysfunction. Results Two thirds (67%) of the older US population suffer from two or more sensory deficits, 27% from just one, and only 6% had none. Impairment of the sense of taste was the most common (74%); 70% had a poor sense of touch; 22% had poor sense of smell; 20% had impaired corrected vision; and 18% had poor corrected hearing. Older adults, men, African Americans, and Hispanics had greater multisensory impairment (all P<0.01). Global sensory impairment largely accounted for the effects of age, gender, and race on the likelihood of impairment of each of the five senses. Conclusion Multisensory impairment is prevalent in older US adults. These data support the concept of a common process that underlies sensory aging across the five senses. Clinicians assessing patients with a sensory deficit should consider further evaluation for additional cooccurring sensory deficits.

The rate of olfactory decline increases with age and is greater among men than women despite adjusting for differences in psychosocial and health conditions, indicating physiologic factors as drivers. African Americans are more likely to experience initial olfactory decline, consistent with an earlier onset of aging among this subgroup.