Targeting oral frailty indicators of late-life cognitive disorders and depression: a systematic review

Background: Oral frailty is an age-related gradual loss of oral function together with a cognitive and physical function decline. Previous systematic reviews and meta-analyses examined the association of some oral frailty indicators with late-life cognitive and late-life depression (LLD). However, none of these studies investigated a large series of possible indicators and outcomes. Objective: To clarify the impact of oral frailty indicators on late-life cognitive disorders and LLD. Design: Systematic review. Subjects: Sixty-three studies (56,520,662 subjects) with 11 oral frailty indicators in four categories: (i) oral health status deterioration, (ii) decline in oral motor skills, (iii) chewing, swallowing, and saliva disorders, and (iv) oral pain. Methods: From database inception to April 24, 2024, six different electronic databases were consulted by two independent researchers assessing the eligibility of 24,045 records against the inclusion criteria and found 63 studies fitting the eligibility requirements. The protocol was registered a priori with PROSPERO (CRD42021249428). Results: Four oral frailty indicators (number of remaining teeth, periodontal disease, difficulties in chewing, and difficulties in swallowing) were associated with late-life cognitive impairment/decline, mild cognitive impairment (MCI), dementia, and LLD. Among categories, oral health status deterioration and chewing, swallowing, and saliva disorders were associated with late-life cognitive impairment/decline, MCI, dementia, and LLD. Decline in oral motor skills was associated with late-life cognitive impairment/decline, while oral pain was related only to LLD. Conclusion: Certain oral frailty indicators may contribute to the development of late-life cognitive disorders and LLD.