Multidimensional oral health indicators and frailty among nursing home residents

Oral health plays an important role in the well-being of older adults requiring long-term care. However, few studies have explored the association between multidimensional oral health indicators and frailty in this population. The aim of this study was to investigate the association between oral health and frailty among older adults residing in Japanese long-term care facilities. A total of 327 nursing home residents aged ≥ 65 years were analyzed. Oral health indicators, including the tongue coating index, oral dryness, masticatory ability, tongue pressure, oral diadochokinesis (ODK) (/pa/, /ta/, and /ka/), rinsing ability, number of remaining and functional teeth, and Functional Oral Intake Scale (FOIS), were assessed by a dentist. Frailty status was evaluated using the 31-item Frailty Index (FI). The median age was 90 years (interquartile range : 85–94), and the mean FI score was 0.32 (standard deviation: 0.10). Participants with oral dryness (regression coefficient [β] = 0.0196; 95% confidence interval [CI]: 0.0003–0.0389) and a lack of rinsing ability (β = 0.0668; 95% CI: 0.0459–0.0878) exhibited significantly higher FI scores than those without these conditions. A higher number of functional teeth (β = −0.0010; 95% CI: −0.0018 to − 0.0002), greater syllable repetition rates for ODK /pa/ (β = −0.0200; 95% CI: −0.0277 to − 0.0123), /ta/ (β = −0.0171; 95% CI: −0.0254 to − 0.0088), and /ka/ (β = −0.0199; 95% CI: −0.0283 to − 0.0114), higher tongue pressure (β = −0.0025; 95% CI: −0.0036 to − 0.0014), and higher FOIS scores (β = −0.0226; 95% CI: −0.0298 to − 0.0154) were significantly associated with lower FI scores. A significant inter-facility variance in the random intercept was observed. These findings suggest that various oral health indicators were associated with frailty among older nursing home residents.