Number of natural teeth and intrinsic capacity among hospitalized older adults in China: a cross-sectional study on the role of social support.

BACKGROUND: Tooth loss is common in older adults and has been associated with adverse health outcomes, but its relationship with intrinsic capacity (IC), a multidimensional indicator of healthy aging, remains insufficiently understood. Whether social support is involved in this association is also unclear. METHODS: This cross-sectional study included 421 hospitalized adults aged 60 years or older who were recruited from Peking Union Medical College Hospital, Beijing, between February and May 2022. The number of natural teeth was assessed by direct visual inspection of the oral cavity by a trained nurse during routine admission assessment. IC was evaluated using six components derived from five World Health Organization domains: locomotion, cognition, vitality, psychological function, hearing, and vision. Participants with impairment in at least one component (IC score ≤ 5 of 6) were classified as having declined IC. Social support was measured using the Multidimensional Scale of Perceived Social Support. Multivariable logistic regression was used to examine the association between natural-tooth count and declined IC. Exploratory structural equation modeling (SEM) was used to assess an indirect statistical pathway involving social support. RESULTS: Among 421 participants (mean age, 71.5 ± 6.3 years; 60.6% male), 66.98% had declined IC. Compared with participants with ≥20 natural teeth, those with < 20 natural teeth had higher odds of declined IC after adjustment for sociodemographic, clinical, and behavioral factors and Charlson Comorbidity Index (OR = 3.11, 95% CI: 1.82-5.32, P < 0.001). When natural-tooth count was modeled continuously, each additional tooth was associated with lower odds of declined IC (OR = 0.96, 95% CI: 0.93-0.98, P = 0.001). In exploratory SEM using the 0-6 IC score, a significant indirect association through social support was observed (β = 0.009, 95% CI: 0.005-0.014, P < 0.001), accounting descriptively for 41.8% of the total statistical association. CONCLUSIONS: Fewer natural teeth were associated with declined IC among hospitalized older adults. Social support may be involved in this association, but the cross-sectional design precludes causal interpretation. These findings support incorporating oral health assessment into geriatric care and warrant longitudinal studies to clarify temporal pathways.