Sarcopenia, dysphagia, and frailty in community-dwelling older adults: An analysis of mediation and moderated mediation models

Sarcopenia, dysphagia, and frailty are geriatric syndromes that commonly occur with age and are associated with various adverse health consequences. Nevertheless, the complex associations among them require further study to be clarified. The objectives of this study were to investigate (1) the potential role of dysphagia as a mediator in the association between sarcopenia and frailty and (2) the potential role of taste and smell dysfunction as a moderator of this mediator effect in community-dwelling older adults. A total of 352 older adults (mean age = 70.48 ± 5.31 years; 57.67% female) enrolled in this cross-sectional study. The SARC-F, Eating Assessment Tool-10 (EAT-10), and Edmonton Frailty Scale (EFS) were used to assess sarcopenia, dysphagia, and frailty, respectively. The Taste and Smell Dysfunction Questionnaire (TSDQ) was employed to assess taste and smell dysfunction. Frailty was present in 21.86%, sarcopenia risk in 39.77%, and dysphagia in 26.99% of the participants. The mediation analysis showed that the SARC-F had a significant effect on the EAT-10 (B = 1.001; p < 0.001), which in turn had a significant effect on the EFS (B = 0.129; p < 0.001). The direct (B = 0.659; p < 0.001), indirect (B = 0.129), and total (B = 0.778; p < 0.001) effects of SARC-F on EFS were significant. Of the association between sarcopenia and frailty, 16.6% was explained by dysphagia. The moderated mediation analysis showed that the TSDQ (B = 0.127; p < 0.001) moderated the association between SARC-F and EAT-10 and that the EAT-10 mediated the association between SARC-F and EFS only in older adults who scored moderate and high on the TSDQ (B = 0.049 and B = 0.114, respectively). The EAT-10 partially mediates the association between the SARC-F and the EFS, implying that sarcopenia affects frailty indirectly via dysphagia. Furthermore, taste and smell dysfunction moderates this mediator effect, with sarcopenia functioning as a mediator in older adults who scored moderate and high on the TSDQ. Therefore, it is plausible to anticipate that if someone has taste and smell dysfunction in addition to sarcopenia, they are more likely to have dysphagia and, ultimately, frailty. These findings emphasize the importance of addressing sarcopenia, taste and smell dysfunction, and dysphagia concurrently in frailty management in older adults.