Aging through the mouth Integrating oral health into multidimensional aging metrics

This thesis examined the multidimensional role of oral health in older adults, aiming to bridge the gap between oral health indicators and dominant frameworks of functional aging. Across six studies using cross-sectional analyses and systematic reviews, it investigated associations between oral health (ranging from oral health–related quality of life and tooth loss to multidimensional oral frailty), and systemic outcomes including nutritional status, bone mineral density, neurodegeneration, cardio-metabolic disease, and intrinsic capacity.
The findings demonstrate that oral health is a clinically meaningful marker of systemic resilience. Poor oral health was consistently associated with underweight and obesity, osteopenia and osteoporosis, cognitive decline, cardio- and cerebrovascular disease, depressive symptoms, and multisystem functional impairment. Tooth loss and composite indicators of oral frailty emerged as robust correlates of adverse aging trajectories in older age.
A central contribution of this thesis is the conceptual consolidation and empirical validation of oral frailty as a multidimensional construct reflecting age-related decline in orofacial structures and function. Oral frailty was shown to operate as a unifying marker of vulnerability across physical, cognitive, vascular, and psychosocial domains. Furthermore, analyses of nationally representative data demonstrated that dentition status is significantly associated with multiple domains of the World Health Organization intrinsic capacity framework.
The thesis argues for the formal integration of oral health indicators into the Frailty Index and intrinsic capacity models. Incorporating oral health would enhance the validity, predictive accuracy, and clinical relevance of contemporary aging assessments, advancing more integrated and person-centered approaches to healthy aging.