Tooth loss, periodontal disease, and cognitive decline in the Atherosclerosis Risk in Communities (ARIC) study

Abstract

Objective The purpose of this prospective study was to investigate whether poor oral health predicted eight-year cognitive function change in predominantly late middle adults in the Atherosclerosis Risk in Communities (ARIC) study. Methods Participants included a subset of ARIC participants aged 52–75 years at 1996–1998 from two study sites: Forsyth County NC and Jackson MS. All subjects completed cognitive function assessments both in 1996–1998 and 2004–2006, and the same subjects received a dental examination at the initial visit. Cognitive assessment consisted of Delayed Word Recall (DWR), Digit Symbol Substitution (DSS), and Word Fluency (WF) tests. In the analysis, cognitive function for 911 dentally screened participants was evaluated, and 558 of 785 dentate participants received comprehensive oral examinations, including periodontal probing. Measures of oral health included dental status, number of teeth, and periodontal disease classified by the Biofilm-Gingival Interface (BGI) index. The generalized estimating equations (GEE) method was used to analyze repeated measures of cognitive scores with adjustment for socio-demographic characteristics and cardiovascular risk factors. Results Of 911 study participants, 13.8% were edentulous. About 13 % of dentally examined participants had periodontal pockets (≥4 mm) with severe bleeding. At the follow-up visit, DWR and WF scores were lower in edentulous compared to dentate people, whereas other oral health measures were not associated with cognitive function. Mean values declined over time for all three cognitive measures, although poor oral health conditions were not associated with greater degree of decline in cognitive function. Conclusions In these late-middle aged adults, complete tooth loss was significantly associated with lower cognitive performance. However, neither edentulism, number of teeth, nor periodontal disease predicted greater subsequent cognitive decline.

Periodontitis, periodontal inflammation, and mild cognitive impairment: A 5‐year cohort study

“…It has been suggested that sites of periodontal infection could be significant sources of inflammatory mediators and bacterial components, which may enter the central nervous system and cause neuronal damage . Although the evidence supporting the potential association between periodontitis and cognitive impairment is increasing, the results from previous studies are not consistent with those from several studies that did not find any significant association between periodontitis and cognitive impairment. It should be noted that there is not enough evidence to draw definite conclusions; additional well‐designed research is warranted in this field.…”

“…A putative link between periodontitis and cognitive impairment/dementia has been reported . There are several possible underlying mechanisms for this association.…”

Tooth Loss and Risk of Dementia in the Community: the Hisayama Study

“…This prospective cohort study of an elderly Japanese population demonstrated an inverse association between number of remaining teeth and risk of development of all‐cause dementia and AD, indicating that subjects with greater tooth loss were at greater risk of onset of dementia. Tooth loss was estimated using data from clinical oral examinations performed by dentists, and dementia subtypes were determined on the basis of brain morphological data (neuroimaging and neuropathology), unlike previous studies . The present prospective cohort study investigated the association between tooth loss evaluated through a professional oral examination and risk of dementia and its subtypes in an elderly general population.…”

Dental deafferentation and brain damage: A review and a hypothesis

“…Examples of DD include: Tooth loss, local and/or generalized periodontal detachment, improper operative or prosthetic restorations, and orthodontic managements and the unavoidable consequence of impaired mastication. These DDs may cause sensory and motor cortical reorganization [1–4], affect cerebral functional streams toward multisensory hubs [5,6], impair gustatory, auditory and olfactory perceptions [7–11], and result in memory and cognition impairment [12–30].…”

“…The greatest risk factor for cognitive decline and Alzheimer's disease in older adults is age itself [31,32]. Accumulating scientific evidence has indicated a correlation between DD and impaired brain functions such as memory loss, cognitive impairment, and even prodromes of AD and dementia [12–30]. A recent review of both animal trials and clinical research [33] has highlighted the causal relationship of mastication on cognitive functions.…”