Oral Frailty as a Marker of Intrinsic Capacity Decline: A Narrative Review on a Multisystemic Ageing Perspective

Background: Global population ageing has intensified the need to identify determinants of functional decline beyond disease-specific measures. Within the World Health Organization framework of intrinsic capacity (IC), oral health has emerged as a potentially important factor in healthy ageing. Objective: To examine oral frailty as a multidimensional condition potentially associated with decline across IC domains in older adults. Methods: This narrative review synthesized current evidence on the relationship between oral frailty and IC within the framework proposed by the World Health Organization. Literature searches were conducted in PubMed, Scopus and Web of Science for studies published between January 2000 and September 2025 using predefined terms related to oral frailty, oral function, ageing, frailty and IC domains. Eligible publications included peer-reviewed original studies, longitudinal cohort studies, systematic reviews and meta-analyses examining oral frailty or oral health indicators in relation to ageing, frailty or IC domains. Findings: Mechanistic, epidemiological and clinical evidence suggested that oral frailty may be associated with decline across cognition, locomotion, vitality, sensory function and psychological well-being through biological, nutritional, neuromuscular, inflammatory and psychosocial pathways. Cross-sectional and longitudinal findings indicated that impaired oral function may be associated with disability, multimorbidity and mortality independently of conventional oral disease indicators. However, available evidence remains limited by heterogeneous definitions and predominantly observational study designs. Conclusions: Oral frailty may represent a multidimensional marker of declining intrinsic capacity and reduced functional resilience in later life. Integrating oral frailty assessment into geriatric care strategies may support interventions aimed at preserving autonomy and promoting healthy ageing.