Oral frailty assessment links brain changes in healthy older adults and predicts future cognitive decline

This study investigated the association between oral frailty and regional brain volumes in cognitively unimpaired older adults. We employed a modified version of the Oral Frailty Five-item Checklist (OF-5) and examined its relationship with brain structural changes using magnetic resonance imaging (MRI). A total of 732 participants who were cognitively unimpaired (mean age 70.32 years), from a community-dwelling Japanese cohort, were included in the study. Oral frailty was assessed using the original OF-5, revised OF-5, and novel revised OF-6 classification that incorporated social factors. Our findings revealed that the revised OF-6 classification demonstrated stronger associations with reduced volumes in multiple brain regions than the original and revised OF-5. Individuals classified as orally frail by the revised OF-6 had significantly lower volumes in areas crucial for cognitive function, including the medial temporal lobe, parahippocampal gyrus, and entorhinal cortex. Furthermore, severe tooth loss (≤9 teeth) and solitary eating were independently associated with lower total brain volume and regional atrophy in areas typically affected by dementia. These findings suggest that when assessed using the revised OF-6 classification, oral frailty may serve as an early indicator of cognitive decline risk in older adults. This study underscores the potential of comprehensive oral health assessments as noninvasive screening tools for identifying individuals at higher risk of dementia, highlighting the complex interplay between oral health, social engagement, and brain structure and suggesting that maintaining good oral health and social connections may play crucial roles in preserving brain volume in regions critical for cognitive function.