Association between oral health and cognitive impairment in older adults: Insights from a Six-year prospective cohort study.

ABSTRACT

OBJECTIVE: This study aims to investigate the relationships between four baseline oral conditions (periodontal status, dental caries, tooth wear, and dentition) and repeated global cognition or domain-specific cognition (memory, executive function, attention, and verbal fluency) in non-demented older adults over time. METHODS: This prospective cohort study (2011-2019) enrolled 516 non-demented community-dwelling older adults (age ≥ 65) to explore the association between oral health and cognitive function. Global and domain-specific cognition were assessed biennially (four repeats) using a battery of neuropsychological tests. The baseline oral health conditions were examined, including periodontal status, dental caries, tooth wear, and dentition. The association of these oral conditions with cognition was evaluated by generalized linear mixed models. Stratified analyses were performed by important covariates. RESULTS: Over time, dental caries was associated with poor memory in two different logical memory tests (ß^= -0.06 and ß^= -0.04). Incomplete dentition with less than 28 teeth was associated with poor performance in attention (ß^= -0.05) and verbal fluency (ß^= -0.03). These associations became more evident in those with an elevated inflammatory marker (IL-6, ß^= -0.11 to -0.08). In contrast, tooth wear was associated with better memory in two different logical memory tests (ß^= 0.33 and ß^= 0.36) and better executive function (ß^= 0.06) over time, and this association became more evident in those with the lowest inflammatory marker (IL-6, ß^= 0.10). CONCLUSIONS: Dental caries and incomplete dentition were associated with poor memory, attention, and verbal fluency performance. Conversely, tooth wear was associated with better memory performance and executive function. CLINICAL SIGNIFICANCE: For early prevention of dementia, an evaluation of multiple dental and periodontal status in older adults helps predict the risk of dementia in the preclinical phase. Maintaining intact tooth structure without caries progression and eventually tooth loss may help prevent the worsening of memory, attention, and verbal fluency over time.