Oral Frailty, Body Mass Index and Grip Strength in Older Adults: A Multicentre Cross‐Sectional Study

Background Oral frailty is a multidimensional state associated with physical decline. This study is to investigate the association between oral frailty and grip strength in older adults, focusing on the moderating role of body mass index (BMI). Methods A multicentre cross‐sectional study was conducted in Beijing, China, between July, 2024 and March, 2026. Participants aged 60 years or older were recruited using convenience sampling from eight communities. Oral frailty was assessed using the Oral Frailty Assessment Tool (OFAT). Grip strength and oral health indicators, including oral motor skills and masticatory function, were measured. Multivariate linear regression and interaction analyses were performed. Results Oral frailty was prevalent in 55.5% of participants. After adjusting for confounders, oral frailty ( β = −0.42, p < 0.001) and decreased oral motor skills ( β = −0.10, p = 0.001) were independently associated with reduced grip strength. A significant interaction effect was identified between oral frailty and BMI ( β = 0.11, p = 0.006). Low BMI significantly amplified the negative impact of oral frailty on grip strength. Conclusions Oral frailty and decreased oral motor skills are core independent factors for reduced grip strength in older adults. The synergistic effect of low BMI and oral weakness suggests that the elderly have a high‐risk phenotype of muscle strength decline. Comprehensive geriatric screening should integrate oral function and nutritional status to identify vulnerable individuals early.