Odor detection thresholds in a population of older adults

Abstract

OBJECTIVE To measure odor detection thresholds and associated nasal and behavioral factors in an older adult population. STUDY DESIGN Cross-sectional cohort study METHODS Odor detection thresholds were obtained using an automated olfactometer on 832 participants, aged 68–99 (mean age 77) years in the 21-year (2013–2016) follow-up visit of the Epidemiology of Hearing Loss Study. RESULTS The mean odor detection threshold (ODT) score was 8.2 (range: 1–13; standard deviation = 2.54), corresponding to a n-butanol concentration of slightly less than 0.03%. Older participants were significantly more likely to have lower (worse) ODT scores than younger participants (p<0.001). There were no significant differences in mean ODT scores between men and women. Older age was significantly associated with worse performance in multivariable regression models and exercising at least once a week was associated with a reduced odds of having a low (≤5) ODT score. Cognitive impairment was also associated with poor performance while a history of allergies or a deviated septum were associated with better performance. CONCLUSION Odor detection threshold scores were worse in older age groups but similar between men and women in this large population of older adults. Regular exercise was associated with better odor detection thresholds adding to the evidence that decline in olfactory function with age may be partly preventable.

Olfaction and Aging: A Review of the Current State of Research and Future Directions

“…Identification of everyday odors may also be assessed without the provision of contextual cues (i.e., free odor identification or odor naming) which is a cognitively effortful task ( Larsson et al., 2016 ; Olofsson et al., 2013 ). A vast number of studies demonstrated impaired olfactory functions in aging ( Choi et al., 2018 ; Hedner et al., 2010 ; Hummel et al., 1997 ; Kern et al., 2014 ; Larsson et al., 2000 ; Larsson, Hedner, et al., 2009 ; Schubert et al., 2017 ; Stuck et al., 2006 ). Age-related impairment is pronounced in odor quality discrimination ( Choudhury et al., 2003 ; Hedner et al., 2010 ; Hummel et al., 1997 ; Kaneda et al., 2000 ) as well as in odor intensity ratings (S. Koskinen & Tuorila, 2005 ).…”

Role of physical exercise type in olfactory deterioration in ageing

“…The few studies demonstrating that regular physical exercise improves olfactory function have focused on odor identification (5,6) , but the effect of regular physical exercise on the odor detection threshold was not robust. Schubert et al (7) found that regular physical exercise was correlated with a reduced risk of having a higher threshold, but suggested that physical exercise may not have a linear relationship with the olfaction threshold. In addition, to the best of our knowledge, none of the previous studies took into account the type of physical exercise.…”

Olfactory impairment in men and mice related to aging and amyloid-induced pathology

“…Schubert et al [ 144 ] measured odor detection thresholds in men and women of advanced age (68–99 years old). They found that older participants (≥ 85 years of age) were significantly more likely to have a worse detection threshold than younger (68–74 years old) participants.…”

“…Data are taken from refs. [ 41 , 43 , 44 , 68 , 78 , 96 , 97 , 117 , 128 , 143 , 144 ]. Y -axis is shown in arbitrary units …”