Improving oral hygiene for better cognitive health: Interrelationships of oral hygiene habits, oral health status, and cognitive function in older adults

Objectives: To explore the interrelationships between oral hygiene habits, oral health status and cognitive function in older adults. Design: A cross-sectional study. Setting and Participants: A total of 371 participants (age 76.79 [7.99] years) were enrolled from June 2020 to November 2021 in an aged care facility. Methods: Cognitive function was screened using the mini-mental state examination (MMSE) with adjusted cut-off points for age and education. Periodontal status (Biofilm-Gingival Interface index based on periodontal probing depth and bleeding on probing), dental status (plaque, calculus, and caries), and tooth loss were assessed through full-mouth examination. Oral hygiene habits were based on self-or informant-reporting. Results: Poor periodontal status was an associated factor for MCI (OR = 2.89, 95% CI = 1.20-6.95), while multiple tooth loss (OR = 4.90, 95% CI = 1.06 similar to 22.59), brushing teeth less than once a day (OR = 2.88, 95% CI = 1.12 similar to 7.45) and delayed dental visits (OR = 2.45, 95% CI = 1.05 similar to 5.68) were associated factors for cognitive impairment. An indirect effect of brushing teeth =2 daily on MMSE score through periodontal status was observed only in older adults without cognitive impairment (Bootstrap-corrected B = 0.17, 95%CI = 0.03 similar to 0.36, SE = 0.08, beta = 0.08). Conclusions and Implications: Adequate toothbrushing might prevent cognitive decline indirectly by improving periodontal health only in older adults without cognitive impairment. Multiple tooth loss, infrequent toothbrushing, and delayed dental visits were associated factors for cognitive impairment. Nursing professionals and health care policymakers should advocate for the improvement of basic oral hygiene in older adults, and provide regular professional oral hygiene care for older adults with cognitive impairment. Patient or Public Contribution: The information on oral health habits of this study was based on an interview with the participants or their caregivers during the study period.