The association between the number of teeth and frailty among older nursing home residents: a cross-sectional study of the CLHLS survey

BACKGROUND: Given that few studies have explored the association between oral health and frailty among older nursing home residents, the purpose of this study was to assess the association between oral health (i.e., the number of teeth and oral behaviors) and frailty in this population using the Chinese Longitudinal Healthy Longevity Survey (CLHLS). METHODS: This was a national cross-sectional study derived from the seventh wave of CLHLS in 2018, consisting of 365 older nursing home residents aged 65 years or older. The frailty index was constructed based on 32 variables consisting of self-rated health status, anxiety, depression, ADL and IADL. Oral health was measured through the number of natural teeth and tooth brushing behavior. Multiple logistic regression was used to identify this association between the number of teeth, oral health behaviors, and frailty. RESULTS: The mean age of this sample was 87.6 (SD = 9.5), with 154 (42.2%) males. The prevalence of frailty and edentulism was 71.2% and 33.4%, respectively. Multiple logistic regression analysis found that the likelihood of frailty decreased with an increased number of teeth, with an OR of 0.94 (95% CI: 0.91–0.98). Compared with participants with edentulism, older adults with 1 to 20 teeth had a lower likelihood of frailty (OR = 0.39, 95% CI: 0.17–0.88); these results were also found in older adults with more than 20 teeth (OR = 0.20, 0.07–0.57). Additionally, older adults who brush their teeth regularly have a lower likelihood of frailty than those who never brush their teeth (OR = 0.37, 95% CI: 0.13–0.99). CONCLUSION: Older nursing home residents who maintain their natural teeth can help lower the risk of frailty, and regular toothbrushing also contributes to decreasing the risk of frailty. Our study emphasizes the importance of oral health, and cohort studies with large-scale samples to address this important issue are warranted in the future. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12877-022-03688-y.