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.

Self-reported olfactory function has poor sensitivity (i.e., people with measured olfactory dysfunction are unlikely to accurately report it). We aimed to identify factors associated with lack of awareness of smell dysfunction. Objective odor identification was evaluated using a validated 5-item test in respondents from the National Social Life, Health, and Aging Project, a representative sample of home-dwelling, US adults ages 57-85 (n = 1468). Self-reported olfaction was assessed with a 5-point Likert scale. Using multivariate logistic regression, we tested factors that might influence inaccuracy of self-reported olfaction, including age, gender, race/ethnicity, education, marital status, cognition, comorbidity, smoking, depression, anxiety, self-rated mental and physical health, and social activity. Among older US adults, 12.4% reported their sense of smell as fair or poor, while 22.0% had objective olfactory dysfunction (≤3 items correct out of 5). Among those with measured olfactory dysfunction, 74.2% did not recognize it; these individuals were more likely to be older, Black, never married, and to have worse cognitive function compared to individuals who recognized their dysfunction (P < 0.05, all). Individuals who lacked awareness of their olfactory dysfunction had the greatest cognitive impairment at 5-year follow-up, followed by individuals aware of their dysfunction and finally normosmics (P < 0.001). Older Americans with measured olfactory dysfunction are unlikely to report it, and those who lack awareness of this dysfunction have distinct demographic, social, and cognitive characteristics. Therefore, clinicians should objectively test patients. Individuals who lack awareness of their olfactory dysfunction have poor cognitive outcomes and should receive additional clinical scrutiny.

Objectives To investigate the relationship between olfactory dysfunction and subsequent diagnosis of dementia. Design Longitudinal study of a population representative of U.S. older adults. Setting Home interviews (National Social Life, Health, and Aging Project). Participants Men and women aged 57 to 85 (N = 2,906). Measurements Objective odor identification ability was measured at baseline using a validated five‐item test. Five years later, the respondent, or a proxy if the respondent was too sick to interview or had died, reported physician diagnosis of dementia. The association between baseline olfactory dysfunction and an interval dementia diagnosis was tested using multivariate logistic regression, controlling for age, sex, race and ethnicity, education, comorbidities (modified Charlson Comorbidity Index), and cognition at baseline (Short Portable Mental Status Questionnaire). Results Older adults with olfactory dysfunction had more than twice the odds of having developed dementia 5 years later (odds ratio = 2.13, 95% confidence interval = 1.32–3.43), controlling for the above covariates. Having more odor identification errors was associated with greater probability of an interval dementia diagnosis (P = .04, 1‐degree of freedom linear‐trend test). Conclusion We show for the first time in a nationally representative sample that home‐dwelling older adults with normal cognition and difficulty identifying odors face higher odds of being diagnosed with dementia 5 years later, independent of other significant risk factors. This validated five‐item odor identification test is an efficient, low‐cost component of the physical examination that can provide useful information while assessing individuals’ risk of dementia. Use of such testing may provide an opportunity for early interventions to reduce the attendant morbidity and public health burden of dementia.

Most measures of cognitive function used in large-scale surveys of older adults have limited ability to detect subtle differences across cognitive domains, and clinical instruments are impractical to administer in general surveys. The Montreal Cognitive Assessment (MoCA) can address this need, but has limitations in a survey context. Therefore, we developed a survey-adaptation of the MoCA, called the MoCA-SA, and describe its psychometric properties in a large national survey. Using a pretest sample of older adults (n=120), we reduced MoCA administration time by 26%, developed a model to accurately estimate full MoCA scores from the MoCA-SA, and tested the model in an independent clinical sample (n=93). The validated 18-item MoCA-SA was then administered to community-dwelling adults aged 62–91 as part of the National Social life Health and Aging Project (NSHAP) Wave 2 sample (n=3,196). In NSHAP Wave 2, the MoCA-SA had good internal reliability (Cronbach α=0.76). Using item-response models, survey-adapted items captured a broad range of cognitive abilities and functioned similarly across gender, education, and ethnic groups. Results demonstrate that the MoCA-SA can be administered reliably in a survey setting while preserving sensitivity to a broad range of cognitive abilities and similar performance across demographic subgroups.

A survey-based adaptation of the MoCA was successfully integrated into a nationally representative sample of older adults, NSHAP Wave 2.