Association of olfactory impairment with indexes of sarcopenia and frailty in community‐dwelling older adults

Abstract

Aim Individuals with olfactory or gustatory impairment often have associated difficulties with food‐related activities. As both functions decline in older adults, we investigated the association of these impairments with sarcopenia/frailty indexes in community‐dwelling older adults. Methods A total of 141 participants (69 men and 72 women, mean age 73.0 years) were enrolled. Odor identification was examined using the Open Essence test. Salty and sweet tastes were assessed using a whole‐mouth gustatory test. Participants underwent evaluation of the appendicular skeletal muscle mass index (ASMI) by InBody720 and grip strength, and determination of the Study of Osteoporotic Fractures frailty index. Results Participants with olfactory impairment (Open Essence ≤7), but not with gustatory impairment, showed a significantly higher prevalence of ASMI and grip strength less than the cut‐off values recommended by the Asian Working Group for Sarcopenia, and Study of Osteoporotic Fractures frailty and/or pre‐frailty status, compared with those without impairment. Multivariate logistic regression analysis showed a significant association of olfactory impairment with ASMI less than the cut‐off value, grip strength less than the cut‐off value, Asian Working Group for Sarcopenia sarcopenia and pre‐frailty/frailty in the Study of Osteoporotic Fractures index in the whole population, and with ASMI less than the cut‐off value and Asian Working Group for Sarcopenia sarcopenia in women, after adjustment. Three (Japanese cypress, wood and roasted garlic) and four (Japanese orange, India ink, menthol and curry) Open Essence odorants were elucidated as the “sarcopenia subset” and “frailty subset,” respectively, and showed higher ability to identify sarcopenia and frailty status, compared with the remaining five odorants. Conclusions These findings suggest that olfactory impairment is closely associated with sarcopenia and/or frailty in community‐dwelling older adults. Geriatr Gerontol Int 2019; 19: 384–391.

The association of frailty with olfactory and gustatory dysfunction in older adults: a nationally representative sample

“…9,53,54 One study of 141 older Japanese participants using objective smell and taste tests found a significant association of mOD with a frailty index, but not mGD. 55 Meanwhile, data from a prospective populationbased study of 1035 Italian persons aged ≥65 years revealed an association between self-reported OD and frailty, which varied according to levels of serum interleukin-6 (IL-6), a marker of inflammation. 56,57 In agreement, our analysis of a nationally representative sample of older adults in the United States identified self-reported olfactory and gustatory dysfunction, as well as measured olfactory dysfunction, as being independently associated with measures of frailty.…”

“…Although few studies examine the relationship between chemosensory dysfunction and frailty, findings have been inconsistent 9,53,54 . One study of 141 older Japanese participants using objective smell and taste tests found a significant association of mOD with a frailty index, but not mGD 55 . Meanwhile, data from a prospective population‐based study of 1035 Italian persons aged ≥65 years revealed an association between self‐reported OD and frailty, which varied according to levels of serum interleukin‐6 (IL‐6), a marker of inflammation 56,57 .…”

Mechanisms Linking Olfactory Impairment and Risk of Mortality

“…Indeed, it was found that idiopathic age-related decline in olfactory function was much smaller in the healthy, nonmedicated, non-smoking population (Mackay-Sim et al, 2006). On the contrary, it was shown that taste and smell disorders were associated with an increased risk of frailty in the older population (Somekawa et al, 2017;Harita et al, 2019). Among the mortality studies, controlling for performance in activities of daily living or frailty score did not attenuate the effect (Pinto et al, 2014;Schubert et al, 2016).…”

Olfactory‐cognitive index distinguishes involvement of frontal lobe shrinkage, as in sarcopenia from shrinkage of medial temporal areas, and global brain, as in Kihon Checklist frailty/dependence, in older adults with progression of normal cognition to Alzheimer's disease

“…Olfactory identification was evaluated using a card‐type olfactory test, the Open Essence (OE) test, with 12 odorants (FUJIFILM Wako Pure Chemical, Osaka, Japan) 12 . According to the OE score, participants were divided into normosmia (OE score 12–7), dysosmia (OE score 6–4) and anosmia (OE score ≤3).…”