Validating a Revised Oral Frailty 5-Item Checklist (OF-5) to Detect Pre-Symptomatic Brain Changes in Cognitively Unimpaired Older Adults

Objective: Oral frailty is associated with an increased risk of cognitive decline, yet practical tools for early identification remain limited. The Oral Frailty 5-item Checklist (OF-5), recently standardized in Japan, does not account for severe tooth loss, which is a known risk factor for brain atrophy. We developed a revised version of the OF-5 that includes the criterion of having nine or fewer teeth. This study aimed to validate the revised OF-5 as a screening tool for detecting early brain structural changes related to dementia risk in cognitively unimpaired older adults. Methods: We analyzed 732 cognitively unimpaired participants from a population-based Japanese cohort (baseline 2016–2018). Oral frailty was assessed using both the original OF-5 and the revised OF-5. Brain volumes were measured by MRI and processed with FreeSurfer. Associations between oral frailty status and regional brain volumes were tested using multivariable-adjusted models, with further adjustment for nutrient intake and food consumption. Results: The revised OF-5, which adds severe tooth loss (≥9 teeth) as a criterion, showed greater sensitivity in detecting dementia-related brain changes than the original version. With the original OF-5, oral frailty was associated only with reduced fusiform gyrus volume (1.088% vs. 1.109% of estimated total intracranial volume eTIV; p < 0.05). In contrast, the revised OF-5 detected broader changes: orally frail participants showed significantly higher white matter hyperintensity (WMH) volume (0.366% vs. 0.302% of eTIV; p < 0.05) and smaller volumes in the medial temporal lobe (1.824% vs. 1.856%), pars triangularis (0.401% vs. 0.412%), and fusiform gyrus (1.080% vs. 1.111%)—all p < 0.05 (FWE-corrected). These associations persisted after adjusting for nutrient intake and food consumption. Conclusions: The revised OF-5 improves identification of pre-symptomatic brain changes in cognitively healthy older adults, independent of nutrition. It may serve as a simple and practical tool for early screening of dementia risk in clinical and community settings.