Periodontal health, cognitive decline, and dementia: A systematic review and meta-analysis of longitudinal studies

Associations between oral health measures and cognitive function in middle aged and older Indian adults

Given India's rise in ageing population and emerging epidemiological evidence of the possible association between poor oral health and cognitive impairment, the present study examined associations between oral health measures and cognitive function using a cross-sectional dataset from Longitudinal Aging Study in India, 2017-2018. Analysis included 56,738 participants aged ≥ 45 years old. Self-reported physician-diagnosed oral health measures included loss of teeth (some or all), presence of painful teeth, ulcers, bleeding and swelling gums, loose teeth, dental cavities or caries, and soreness or cracks in the corners of the mouth. Cognitive function was assessed using a battery of neurocognitive tests across five domains: memory, orientation, arithmetic function, executive function, and object naming. Findings from multivariable regression models revealed that participants who lost all their teeth had lower cognition scores by 0.65 points [β= -0.65, 95% CI: -0.97, -0.33] than those who had not lost any teeth. An unexpected positive association was found between three or more oral conditions and cognitive performance [β = 0.53, 95% CI: 0.28, 0.77] that needs further investigation. Findings suggest that oral health is associated with cognitive function and there is a need to promote policies targeted at improving the oral health infrastructure and health education.

"Chew on This: Oral health is associated with cognitive function among Canadians enrolled in the Canadian Longitudinal Study on Aging"

OBJECTIVES

Life expectancy has increased globally, leading to a higher proportion of older adults, particularly in developed countries like Canada. This demographic shift strains healthcare systems and is associated with an increased risk of dementia, a condition characterised by cognitive decline. Oral health has emerged as a potential modifiable risk factor for dementia, yet the evidence remains conflicting. This study examines the association between oral health parameters and cognitive functioning in the Canadian population, utilizing data from the Canadian Longitudinal Study on Aging (CLSA).

METHODS

A cross-sectional analysis was conducted using baseline data from the comprehensive cohort of the CLSA, comprising 30,097 participants aged 45-85 years. Oral health was assessed via self-reported oral health (SROH) and masticatory ability (MA). Cognitive function was evaluated using a battery of neuropsychological tests, and a Cognitive Impairment Indicator (CII) was derived. Logistic regression models were employed to examine the association between oral health and cognitive impairment, adjusting for confounders.

RESULTS

We found that poor SROH was not significantly associated with cognitive impairment (OR = 1.19, 95 % CI = 0.63-2.09), while inadequate MA was significantly associated with higher odds of cognitive impairment (OR = 2.82, 95 % CI = 1.82-4.25).

CONCLUSION

The findings suggest a significant association between perceived MA and cognitive impairment within this cohort.. These results suggest that perceived ability to chew could be a potentially modifiable risk factor for cognitive decline. Further research is warranted to explore the mechanisms underlying these associations and to develop targeted preventive strategies.

CLINICAL SIGNIFICANCE

This paper highlights that middle aged and elderly Canadians with inadequate MA have a 2.82 times higher odds of experiencing cognitive impairment. Addressing chewing difficulties may serve as a modifiable risk factor for early cognitive decline, offering a potential window of opportunity to slow down the process of cognitive decline among aging populations.

Public Periodontal Screening Increases Subsequent Regular Dental Visits: The Life Study

INTRODUCTION

A public oral health screening, periodontal disease screening, has been implemented in Japan, but it remains unclear whether screening encourages subsequent regular dental visits. This study aimed to examine whether people who underwent periodontal disease screening were more likely to regularly visit dentists after undergoing the screening than before using a difference-in-differences (DID) approach.

METHODS

This study used health care claims data of municipality residents who underwent periodontal disease screening in 2017 or 2018. For each screening recipient, 4 individuals were extracted from those who did not undergo screening as controls. In the DID analysis, we assessed the change in the proportion of dentist visits at least once every 180 d after undergoing screening.

RESULTS

A total of 4,050 participants were included in the analysis. The proportion of participants visiting dentists was consistent throughout the study period (approximately 45%) among the participants who did not undergo the screening. However, among the participants who underwent the screening, while the proportion who visited dentists was consistent before screening (approximately 60%), the proportion was higher after screening (1-180 d after, 81.2%). DID analysis indicated that the proportion increased by 12.9% after the screening. In addition, the age-subgroup DID estimates were higher in the younger population (aged 20-35 y, 13.9%; 40-55 y, 12.8%; 60 y, 12.6%).

CONCLUSIONS

Among people who underwent periodontal disease screening, a higher proportion visited dentists after undergoing the screening than before, suggesting that periodontal disease screening was associated with an increase in subsequent regular dental visits.Knowledge Transfer Statement:Our results provide evidence that a public oral health screening could increase regular dental visits, which has the potential to improve and maintain people's oral health, especially in the younger population.

Clinical significance analysis of microRNA-199a-3p in gingival crevicular fluid for patients with chronic periodontitis

OBJECTIVE

The aim was to investigate the clinical performance of microRNA-199a-3p (miR-199a-3p) in patients with chronic periodontitis.

METHODS

91 patients with chronic periodontitis and 78 healthy individuals were enrolled for the research subjects. MiR-199a-3p expression was detected using real-time quantitative PCR (RT-qPCR) assay. Pearson correlation analysis was used for the relevance of miR-199a-3p with inflammatory mediators. Receiver operating characteristic (ROC) and logistic regression were conducted for the evaluation of the diagnostic performance and risk factors of chronic periodontitis. Bioinformatics analysis was utilized for miR-199a-3p-related genes.

RESULTS

MiR-199a-3p was distinctly decreased in gingival crevicular fluid from patients with chronic periodontitis. The area under the curve (AUC) was 0.978 to discriminate chronic periodontitis patients from healthy individuals. The negative correlation was observed between miR-199a-3p and inflammatory factors. Logistic regression showed that miR-199a-3p was an independently protective factor for the occurrence of chronic periodontitis. Bioinformatics analysis revealed that the predictive regulated genes of miR-199a-3p mainly concentrated in inflammatory-associated signaling pathways.

CONCLUSION

MiR-199a-3p was attenuated in patients with chronic periodontitis and an underlying diagnostic biomarker for the disease.

Multivariate longitudinal clustering reveals neuropsychological factors as dementia predictors in an Alzheimer's disease progression study

Dementia due to Alzheimer's disease (AD) is a multifaceted neurodegenerative disorder characterized by various cognitive and behavioral decline factors. In this work, we propose an extension of the traditional k-means clustering for multivariate time series data to cluster joint trajectories of different features describing progression over time. The algorithm we propose here enables the joint analysis of various longitudinal features to explore co-occurring trajectory factors among markers indicative of cognitive decline in individuals participating in an AD progression study. By examining how multiple variables co-vary and evolve together, we identify distinct subgroups within the cohort based on their longitudinal trajectories. Our clustering method enhances the understanding of individual development across multiple dimensions and provides deeper medical insights into the trajectories of cognitive decline. In addition, the proposed algorithm is also able to make a selection of the most significant features in separating clusters by considering trajectories over time. This process, together with a preliminary pre-processing on the OASIS-3 dataset, reveals an important role of some neuropsychological factors. In particular, the proposed method has identified a significant profile compatible with a syndrome known as Mild Behavioral Impairment (MBI), displaying behavioral manifestations of individuals that may precede the cognitive symptoms typically observed in AD patients. The findings underscore the importance of considering multiple longitudinal features in clinical modeling, ultimately supporting more effective and individualized patient management strategies.

[Prevotella nigrescens exacerbates periodontal inflammation and impairs cognitive function in mice]

OBJECTIVES

To investigate the effects of periodontitis induced by Prevotella nigrescens (Pn) combined with ligation on cognitive functions in mice.

METHODS

Twenty-four C57BL/6J mice were randomly divided into control group, ligation group, and ligation + Pn treatment (P+Pn) group. Experimental periodontitis was induced by silk ligation of the first molars followed by topical application of Pn for 6 weeks. After modeling, alveolar bone resorption was assessed using micro-CT and histological analysis. Learning and memory abilities of the mice were evaluated using open field test (OFT), novel object recognition test (NORT), and Morris water maze test (MWM). Seven weeks after the start of modeling, the mice were sacrificed for examining histopathological changes in the hippocampus using HE and Nissl staining.

RESULTS

After 6 weeks of molar ligation, micro-CT revealed horizontal alveolar bone resorption and furcation exposure in the mice, and histological analysis showed apical migration of the junctional epithelium, epithelial ridge hyperplasia, and lymphocyte infiltration, and these changes were obviously worsened in P+Pn group. Alveolar bone height decreased significantly in both ligation groups compared to the control group. Cognitive tests showed that the mice in both of the ligation groups traveled shorter distances in OFT, showed reduced novel object preference in NORT, and exhibited longer escape latencies in MWM, and the mice in P+Pn group had significantly poorer performances in the tests. Histologically, obvious neuronal cytoplasmic degeneration, necrosis, nuclear pyknosis, vacuolation, and reduced Nissl bodies and viable neurons were observed in the hippocampal regions of the mice in the two ligation groups.

CONCLUSIONS

Pn infection aggravates alveolar bone destruction, accelerates necrosis and causes morphological abnormalities of neuronal cells in the hippocampus to reduce cognitive functions of mice with periodontitis.

Association between periodontal disease and age-related cognitive impairment: a narrative review

BACKGROUND

Previous studies have shown associations between periodontal disease and age-related cognitive impairment. However, little is known about the different cognitive functions that may be affected in patients with periodontal disease.

METHODS

We reviewed the recent literature to better understand the bidirectional relationship between cognitive function and periodontal disease, and to explore the cognitive assessments that may be useful when investigating this relationship. We also reviewed the literature around improving periodontal health in older adults presenting with cognitive impairment, which may improve their cognition.

RESULTS

There is a bidirectional relationship between periodontal disease and cognitive impairment. We also found that visuospatial function, attention, memory, and language are important cognitive domains that may be impaired in older people with periodontal disease, possibly because these factors are associated with the ability to adequately brush one's teeth. Furthermore, we noted that the choice of cognitive assessment may be particularly important when studying cognitive function in relation to periodontal health. To improve periodontal health in older people with cognitive impairment, partner-assisted interventions, adequate toothbrushing, and the use of a powered toothbrush have all been proposed. The early initiation of regular oral care visits, education for individuals, improving cooking skills, and dietary/caloric restrictions may also contribute to improving periodontal health.

CONCLUSIONS

The bidirectional nature of the relationship between periodontal health and cognitive function is important for older adults presenting with cognitive impairment. Furthermore, improvements in periodontal health may help to improve cognitive impairment. The appropriate assessment of cognitive function will contribute to preserving and improving oral health in older people with periodontal disease.

Guidelines for the standardization of pre-analytical variables for salivary biomarker studies in Alzheimer's disease research: An updated review and consensus of the Salivary Biomarkers for Dementia Research Working Group

There is a pressing need for accessible biomarkers with high diagnostic accuracy for Alzheimer's disease (AD) diagnosis to facilitate widespread screening, particularly in underserved groups. Saliva is an emerging specimen for measuring AD biomarkers, with distinct contexts of use that could complement blood and cerebrospinal fluid and detect various analytes. An interdisciplinary, international group of AD and related dementias (ADRD) researchers convened and performed a narrative review of published studies on salivary AD biomarkers. We critically appraised the current state of the literature, examining both consistencies and discrepancies in existing pre-analytical variables and methodologies. We discussed how various pre-analytical variables could influence the detection and quantification of salivary biomarkers, showed technologies available to standardize collection procedures, and proposed a standardized pre-analytical protocol to guide future studies on salivary AD biomarker examinations. We identified potential contexts of use, gaps, and priorities and proposed future research directions. HIGHLIGHTS: Given its non-invasive nature, wider accessibility, and cultural acceptability, particularly in low-resourced settings, saliva is a biofluid complementary to blood and CSF. Current salivary AD biomarker studies do not control for many confounding pre-analytical variables during the sampling process, potentially leading to inaccurate salivary biomarker readings and conclusions, contributing to conflicting findings. Reviewing the current literature, including the consistencies and non-consistencies observed in the existing parameters and methodologies, discussing how they can affect salivary AD biomarker detection and quantification. Proposing a standardized salivary pre-analytical protocol, identifying the gaps and prioritizations needed to move this area forward, proposing future directions and potential contexts of use.

The Detection of Porphyromonas Gingivalis in Geriatrics and Its Associated Periodontal and Clinical Factors

BACKGROUND

Porphyromonas gingivalis is one of the important pathogens in the initiation and progression of periodontitis. The findings regarding the bacterium and periodontal status in geriatric subjects are not widely reported. Bacterial analysis is needed to provide more insight regarding the severity of the disease. This study evaluated the presence of P. gingivalis in the oral cavity of geriatric patients and found a significant association between P. gingivalis infection and medical illness.

METHODS

Periodontal pocket samples were obtained from 32 geriatrics who were chosen randomly from health clinics. Clinical periodontal parameters were recorded during the oral examination. Samples were subjected to DNA extraction and polymerase chain reaction (PCR) amplification. The identification of P. gingivalis by PCR assay was determined based on the P. gingivalis 16S rRNA subunit amplification. Medical illnesses of patients were recorded. Mild cognitive impairment was diagnosed according to cognitive score assessment and daily function.

RESULTS

Approximately 90.63% (n=29) of geriatric patients had periodontitis. The presence of P. gingivalis was significantly associated with periodontal depth and clinical attachment loss (p = 0.037). The extension of periodontal disease, cognitive impairment status, and diabetes status are highly associated with P. gingivalis. Conclusion: Due to asymptomatic periodontal disease in the early phase, early screening of bacterial detection and oral public health awareness is crucial, especially among elderly groups who are smokers and diabetics. P. gingivalis infection is associated with worsening geriatric periodontitis. Adequate oral care and comorbidity control among geriatrics are indeed crucial to preventing disease progression. It is important to improve and modify the local diabetic checklist protocol for geriatric diabetic patients by incorporating oral health and oral microbiome assessments, as well as cognitive assessments.

Tooth loss explains income inequalities in dementia

OBJECTIVES

Socioeconomic inequalities in oral health and dementia exist worldwide. This study investigated the mediating effects of tooth loss on the association between income and dementia.

METHODS

This study used data from the Japan Gerontological Evaluation Study, which targeted people aged ≥65 years. The explanatory variable was equivalent income in 2010. The outcome variable was dementia incidence between 2010 and 2022. Cox proportional hazard regression was used to examine the association between income and dementia incidence, adjusting for confounders. We performed causal mediation analyses to evaluate the extent to which the number of natural teeth mediates the association.

RESULTS

Among the 21,306 participants, the mean age was 73.4 years, and 53.5 % were females. The cumulative incidence of dementia was 19.7 % for people with higher incomes and 24.0 % for those with lower incomes. People with lower incomes had fewer teeth (the prevalence of having ≥20 teeth: 42.2 % in higher incomes and 31.1 % in lower incomes). Lower income was associated with dementia after adjusting for confounders (Hazard ratio (HR) [95 % confidence interval (CI)]: 1.18 [1.10; 1.26]), which was partially attenuated by controlling for the number of teeth (HR [95 % CI]: 1.17 [1.09; 1.25]). Causal mediation analysis demonstrated that the proportion mediated by the number of teeth was 6.6 %.

CONCLUSIONS

Our study found that tooth loss partially mediated the association between income and dementia. Preventing tooth loss appears to reduce inequalities in dementia among older people.

CLINICAL SIGNIFICANCE

Tooth loss has mediating effects on the association between income and dementia. Strategies for maintaining natural teeth seem effective in reducing the socioeconomic inequalities of dementia.

Periodontal Indices as Predictors of Cognitive Decline: Insights from the PerioMind Colombia Cohort

Background: Poor oral health and periodontitis have been epidemiologically linked to cognitive decline and mild cognitive impairment (MCI) in older adults. However, specific metrics directly linking these clinical signs are exceedingly limited. Methods: To address this gap and develop novel tools to help clinicians identify individuals at risk of cognitive decline, we established the PerioMind Colombia Cohort, comprising elderly Colombian subjects who underwent comprehensive neurocognitive and periodontal evaluations. Results: The results revealed that subjects diagnosed with MCI exhibited significantly higher scores in specific periodontal indices, including gingival erythema and pocket depth parameters. The predictive model identified positive associations with MCI, with gingival erythema showing the strongest correlation, followed by the presence of periodontitis and variations in pocket depth measurements. Additionally, lower educational attainment was associated with a higher likelihood of being classified in the periodontitis-MCI group. Conclusions: Here, we show that specific altered periodontal metrics are associated with MCI diagnosis, and the generated results provide defined metric ranges for identifying individuals at risk. Upon validation in larger cohorts, the findings reported here could offer dental practitioners and clinicians innovative tools to identify individuals at risk of MCI and age-related dementias through routine oral health assessments, thereby enabling more accessible and highly sought-after early intervention strategies in both developing and developed countries.

Alzheimer's Disease and Porphyromonas gingivalis: Exploring the Links

Recent research highlights compelling links between oral health, particularly periodontitis, and systemic diseases, including Alzheimer's disease (AD). Although the biological mechanisms underlying these associations remain unclear, the role of periodontal pathogens, particularly Porphyromonas gingivalis, has garnered significant attention. P. gingivalis, a major driver of periodontitis, is recognized for its potential systemic effects and its putative role in AD pathogenesis. This review examines evidence connecting P. gingivalis to hallmark AD features, such as amyloid β accumulation, tau hyperphosphorylation, neuroinflammation, and other neuropathological features consistent with AD. Virulence factors, such as gingipains and lipopolysaccharides, were shown to be implicated in blood-brain barrier disruption, neuroinflammation, and neuronal damage. P. gingivalis-derived outer membrane vesicles may serve to disseminate virulence factors to brain tissues. Indirect mechanisms, including systemic inflammation triggered by chronic periodontal infections, are also supposed to exacerbate neurodegenerative processes. While the exact pathways remain uncertain, studies detecting P. gingivalis virulence factors and its other components in AD-affected brains support their possible role in disease pathogenesis. This review underscores the need for further investigation into P. gingivalis-mediated mechanisms and their interplay with host responses. Understanding these interactions could provide critical insights into novel strategies for reducing AD risk through periodontal disease management.

Association of tooth location, occlusal support and chewing ability with cognitive decline and incident dementia

AIM

Emerging evidence suggests association of tooth loss with impaired cognition. However, the differential effects of anterior versus posterior tooth loss, occlusal support loss and chewing ability are not considered comprehensively.

MATERIALS AND METHODS

We conducted cross-sectional (N = 4036) and longitudinal analyses (N = 2787) on data from Health 2000 and 2011 Surveys for associations of posterior occlusal support loss, anterior versus posterior tooth loss, and chewing ability with baseline cognition and 11-year cognitive decline. Additionally, 15-year incident dementia risk was investigated (N = 4073).

RESULTS

After considering relevant confounders and potential reverse causality bias, posterior occlusal support loss significantly increased dementia risk across all categories indicative of posterior occlusal support loss (hazard ratios [HRs] between 1.99 and 2.89). Bilateral inadequate posterior occlusal support was associated with 11-year decline in overall cognition (odds ratio [OR] = 1.48:1.00-2.19), and unilateral inadequate posterior occlusal support with total immediate (OR = 1.62:1.14-2.30) and delayed recall decline (OR = 1.45:1.03-2.05). Moreover, posterior tooth loss was associated with dementia (HR = 2.23:1.27-3.91) and chewing ability with total immediate decline (OR = 1.80:1.04-3.13).

CONCLUSIONS

Posterior tooth and occlusal support loss significantly increases dementia risk. The impact of posterior occlusal support loss appears to be dose-dependent, and this effect is distinct from that of dentures. Dental healthcare services should be particularly attentive to the state of posterior dentition. Further studies exploring possible mechanisms are warranted.

Associations between tooth loss, denture use, and dementia in older Taiwanese adults

BACKGROUND

The literature has mainly focused on the association between tooth loss and dementia, and evidence regarding the separate and joint effects of tooth loss and denture use on the risk of dementia is limited. This study investigated the links among tooth loss, denture use, and dementia risk in Taiwanese adults aged 65 years or older.

METHODS

This retrospective cohort study utilized data from the 2009 National Health Interview Survey and 2008-2017 National Health Insurance claim records, including the records of 2247 individuals free from dementia treatment in 2008-2009. Dementia diagnoses were tracked until 2017. The Cox proportional hazards model was used to calculate hazard ratios (HRs) for exploring the correlations among tooth loss, denture use, and dementia risk.

RESULTS

Older adults with 20 or more natural teeth and dentures had the lowest dementia incidence (1.43 per 100 person-years). Those with <20 natural teeth, with or without dentures, experienced high dementia incidence rates of 2.31 and 3.33 per 100 person-years, respectively. After adjusting for various factors (i.e., sociodemographic characteristics, health conditions/comorbidities, and lifestyles), having <20 natural teeth or not using dentures was associated with non-significantly increased HRs of 1.30 (95% CI, 0.99-1.71) and 1.20 (95% CI, 0.95-1.52). Subgroup analysis revealed that compared to older adults with 20 or more natural teeth and dentures, those with <20 natural teeth and not wearing dentures had a significantly increased risk of dementia (adjusted HR, 1.57; 95% CI, 1.04-2.37).

CONCLUSION

This study found that having <20 natural teeth and not using dentures was significantly associated with an increased risk of dementia in Taiwanese individuals aged 65 years or above.

Oral microbiome and nitric oxide biomarkers in older people with mild cognitive impairment and APOE4 genotype

Apolipoprotein E4 (APOE4) genotype and nitric oxide (NO) deficiency are risk factors for age-associated cognitive decline. The oral microbiome plays a critical role in maintaining NO bioavailability during aging. The aim of this study was to assess interactions between the oral microbiome, NO biomarkers, and cognitive function in 60 participants with mild cognitive impairment (MCI) and 60 healthy controls using weighted gene co-occurrence network analysis and to compare the oral microbiomes between APOE4 carriers and noncarriers in a subgroup of 35 MCI participants. Within the MCI group, a high relative abundance of Neisseria was associated with better indices of cognition relating to executive function (Switching Stroop, rs = 0.33, P = 0.03) and visual attention (Trail Making, rs = -0.30, P = 0.05), and in the healthy group, Neisseria correlated with working memory (Digit Span, rs = 0.26, P = 0.04). High abundances of Haemophilus (rs = 0.38, P = 0.01) and Haemophilus parainfluenzae (rs = 0.32, P = 0.03), that co-occurred with Neisseria correlated with better scores on executive function (Switching Stroop) in the MCI group. There were no differences in oral nitrate (P = 0.48) or nitrite concentrations (P = 0.84) between the MCI and healthy groups. Linear discriminant analysis Effect Size identified Porphyromonas as a predictor for MCI and Prevotella intermedia as a predictor of APOE4-carrier status. The principal findings of this study were that a greater prevalence of oral P. intermedia is linked to elevated genetic risk for dementia (APOE4 genotype) in individuals with MCI prior to dementia diagnosis and that interventions that promote the oral Neisseria-Haemophilus and suppress Prevotella-dominated modules have potential for delaying cognitive decline.

Association Between Severe Periodontitis and Cognitive Decline in Older Adults

(1) Background: Periodontal disease, a progressive inflammatory condition, disrupts the oral microbiome and releases inflammatory cytokines, leading to systemic issues, including cognitive decline. This study investigates the association between severe periodontitis and cognitive decline, exploring the role of alkaline phosphatase (ALP), an enzyme linked to systemic inflammation, as an effect modifier. (2) Methods: We analyzed cross-sectional data from the 2013-2014 National Health and Nutrition Examination Survey (NHANES). Severe periodontitis was defined using the Centers for Disease Control and Prevention (CDC) and the American Academy of Pediatrics (AAP) case definition. A weighted multivariable logistic regression model assessed the association between severe periodontitis and cognitive decline. An interaction term examined ALP's role as an effect modifier. (3) Results: This study included 1265 participants aged 65 and older. After adjusting for confounders, each one-point increase in cognitive function score was associated with a 2% decrease in the odds of severe periodontitis (OR = 0.98; 95% CI = 0.97-0.99; p = 0.008). ALP was a significant effect modifier in the relationship between severe periodontitis and cognitive decline. (4) Conclusions: This study, using a representative U.S. adult population aged 65 and over, suggests that lower cognitive performance correlates with higher likelihood of severe periodontitis. ALP enhances the association between severe periodontitis and cognitive decline.

Associations between measured masticatory function and cognitive status: A systematic review

OBJECTIVE

This systematic review aimed to provide an overview of the most recent evidence on the association between measured masticatory function and cognitive status.

MATERIALS AND METHODS

Literature and manual searches were conducted using three electronic databases (PubMed, Web of Science and CINAHL). Observational studies published between 2011 and 2021 investigating the association between masticatory function, dementia and cognitive status in adult humans were abstracted and reviewed by three reviewers. Studies that assessed participants' masticatory function using objective and subjective measurements and that individually examined its association with cognitive function were included. The included studies were divided into cross-sectional and cohort studies, and the quality of each study was analysed using critical appraisal skills checklists. Additionally, the main conclusions and strength of the evidence were assessed for each article.

RESULTS

A total of 21 studies (11 cross-sectional studies that objectively evaluated masticatory function, 9 cross-sectional studies that subjectively evaluated masticatory function and 1 prospective cohort study) were evaluated. The poorer masticatory function was associated with lower cognitive status even after adjusting for potential risk factors of dementia in four of 11 and six of nine cross-sectional studies where the masticatory function was respectively evaluated objectively and subjectively. One prospective cohort study also demonstrated that masticatory function, as evaluated based on measurements of occlusal force, predicted cognitive decline during the follow-up period.

CONCLUSION

Several studies demonstrated a positive association between masticatory function and cognitive status. However, further studies, particularly longitudinal studies, are required to determine whether the association is causal.

Tooth loss mediates the association between smoking and an increased risk of dementia among older adults: The JAGES prospective cohort study

AIM

Tooth loss has various causes; however, its cause-specific effects on health outcomes remain unclear. This study evaluated whether the association between past/current smoking and risk of dementia was mediated by tooth loss.

MATERIALS AND METHODS

This 9-year-follow-up prospective cohort study targeted adults aged ≥65 years. Dementia incidence during 2013-2019, smoking status (never, past/current) in 2010 and the number of remaining teeth (≤19, ≥20) in 2013 were the outcome, exposure and mediator, respectively. We used causal mediation analysis to fit the Cox proportional hazards model and estimated the hazard ratio (HR) and 95% confidence interval (CI) of the natural indirect effect (NIE) of smoking on dementia incidence through tooth loss and their mediated proportions.

RESULTS

Among 32,986 participants (mean age 72.6 years [1 SD = 5.4]; men 48.4%), the dementia incidence during follow-up was 2.11/100 person-years. Tooth loss significantly mediated the association between past/current smoking and dementia incidence; the NIE of fewer remaining teeth for past/current smokers compared to never smokers was HR = 1.03 (95% CI: 1.02-1.05), and the mediated proportion was 18.0%.

CONCLUSIONS

Tooth loss significantly mediates the association between past/current smoking and an increased risk of dementia among older adults.

Exploring the link between tooth loss, cognitive function, and brain wellness in the context of healthy aging

AIMS

The aim of this study was to evaluate the utility of using MRI-derived tooth count, an indirect and nonspecific indicator of oral/periodontal health, and brain age gap (BAG), an MRI-based measure of premature brain aging, in predicting cognition in a population of otherwise healthy adults.

METHODS

This retrospective study utilized data from 329 participants from the University of South Carolina's Aging Brain Cohort Repository. Participants underwent neuropsychological testing including the Montreal Cognitive Assessment (MoCA), completed an oral/periodontal health questionnaire, and submitted to high-resolution structural MRI imaging. The study compared variability on cognitive scores (MoCA) accounted for by MRI-derived BAG, MRI-derived total tooth count, and self-reported oral/periodontal health.

RESULTS

We report a significant positive correlation between the total number of teeth and MoCA total scores after controlling for age, sex, and race, indicating a robust relationship between tooth count and cognition, r(208) = .233, p < .001. In a subsample of participants identified as being at risk for MCI (MoCA <= 25, N = 36) inclusion of MRI-based tooth count resulted in an R2 change of .192 (H0 = 0.138 → H1 = 0.330), F(1,31) = 8.86, p = .006. Notably, inclusion of BAG, a valid and reliable measure of overall brain health, did not significantly improve prediction of MoCA scores in similar linear regression models.

CONCLUSIONS

Our data support the idea that inclusion of MRI-based total tooth count may enhance the ability to predict clinically meaningful differences in cognitive abilities in healthy adults. This study contributes to the growing body of evidence linking oral/periodontal health with cognitive function.

Infectious Disease as a Modifiable Risk Factor for Dementia: A Narrative Review

This narrative review examines infectious diseases as modifiable risk factors for dementia, particularly in the context of an aging global population. As the prevalence of Alzheimer's disease and related dementias is expected to rise, prevention has become increasingly important due to the limited efficacy of current treatments. Emerging evidence links specific infectious diseases to increased dementia risk, possibly through mechanisms like neuroinflammation and disruption to normal cell function. Here, we review findings on how viral and bacterial infections contribute to dementia and explore potentially preventive measures, including vaccinations and antiviral treatments. Studies indicate that vaccinations against influenza, herpes zoster, and hepatitis, as well as antiviral treatments targeting human herpesvirus, could reduce the incidence of dementia. Additionally, non-pharmaceutical interventions during pandemics and in long-term care settings are highlighted as effective strategies for reducing the spread of infectious diseases, potentially lowering dementia risk. Putative mechanisms underlying the protective effects of these interventions suggest that reducing systemic inflammation may be important to their efficacy. While the currently available evidence suggests at best an association between some infectious diseases and dementia, this narrative review emphasizes the need to incorporate infectious disease prevention into broader public health strategies to potentially mitigate the growing burden of dementia. Further research is required to explore these preventive measures across diverse populations and to deepen our understanding of the biological mechanisms involved.

Diagnostic Potential of Salivary Interleukin-1β and IL-10 for Distinguishing Periodontal Health From Periodontitis and Stable From Unstable Periodontitis: A Case-Control Study

Objective: This case-control study aimed to investigate the diagnostic accuracy of salivary interleukin (IL)-1β, IL-10, and IL-1β/IL-10 ratio to discriminate periodontitis from periodontal health and stable from unstable periodontitis. Methods: Saliva samples were collected from 135 (healthy on an intact periodontium = 45 [as healthy control], stable periodontitis = 39, and unstable periodontitis = 51) participants, and then clinical periodontal parameters were recorded. An enzyme-linked immunosorbent assay was used to determine salivary levels of IL-1β and IL-10. Area under the curves (AUCs), sensitivity, and specificity of IL-1β, IL-10, and IL-1β/IL-10 were estimated to discriminate between groups. Result: The level of salivary IL-1β was significantly higher in unstable periodontitis than in stable periodontitis and healthy control groups (426 ± 59, 247 ± 55, and 204 ± 36 pg/ml [picograms per milliliter], respectively). While the level of salivary IL-10 was significantly higher in the control group (360.7 ± 80.5 pg/ml) than unstable periodontitis group (146.92 ± 1.8 pg/ml), no significant difference was found between the control and stable periodontitis (317.04 ± 59.8 pg/ml) groups. IL-1β, IL-10, and IL-1β/IL-10 had significant diagnostic accuracy for differentiating healthy control from unstable periodontitis (AUCs = 0.99, 0.96, and 1; sensitivity = 0.98,1, and 1; specificity = 0.95, 0.95, and 1, respectively). Similarly, they showed significant diagnostic accuracy in distinguishing unstable from stable periodontitis (AUCs = 0.98, 0.99, and 1; sensitivity = 0.94, 1, and 1; specificity = 0.94, 0.97, and 1, respectively). Conclusion: Salivary IL-1β, IL-10, and IL-1β/IL-10 have a high potential to discriminate healthy control from periodontitis and stable from unstable periodontitis. Trial Registration: ClinicalTrials.gov identifier: NCT05722613.

A Comparative Analysis of Oral Health and Self-Rated Health: 'All of Us Research Program' vs. 'Health and Retirement Study'

Poor oral health can impact overall health. This study assessed the association between dental factors (dentate status and dental utilization) and self-rated health (S-RH) among older adults in two cross-sectional datasets: (1) NIH "All of Us (AoU) Research Program" (May 2018-July 2022 release) and (2) U.S. nationally representative "Health and Retirement Study" (HRS) 2018 wave. Participants aged ≥ 51 years were included in these analyses if (1) from AoU, they had clinical dental and medical data from electronic health records (EHRs) and surveys (n = 5480), and (2) from HRS, they had dental and socio-demographic survey data (n = 14,358). S-RH was dichotomized (fair/poor vs. better) and analyzed with logistic regression. Sample survey weights for HRS and stratification and averaging AoU results used the weighted HRS race-ethnicity and age distribution standardized respective analyses to the U.S. population. Fair/poor S-RH was reported by 32.6% in AoU and 28.6% in HRS. Dentate status information was available from 7.7% of AoU EHRs. In population-standardized analyses, lack of dental service use increased odds of fair/poor S-RH in AoU, OR (95% CI) = 1.28 (1.11-1.48), and in HRS = 1.45 (1.09-1.94), as did having diabetes, less education, and ever being a smoker. Having no natural teeth was not statistically associated with fair/poor S-RH. Lack of dental service was positively associated with fair/poor S-RH in both datasets. More and better oral health information in AoU and HRS are needed.

Tooth Loss in Periodontitis Patients-A Risk Factor for Mild Cognitive Impairment: A Systematic Review and Meta-Analysis

BACKGROUND

Periodontal disease and tooth loss have been long suggested as risk factors of mild cognitive impairment. The underlying mechanisms could be systemic chronic inflammatory mediators, direct pathologic challenge to the nervous system, malnutrition and/or loss of neurosensory stimulation input causing brain atrophy. This review aimed to examine the existing literature studies linking the effect of periodontal disease and tooth loss on the development of mild cognitive impairment.

METHODS

A systematic review using PEO was conducted. Three electronic databases, namely Embase, Medline and DOSS (UCLan), were searched for relevant articles published up to April 2023. Google Scholar and a hand search were also conducted to ensure no relevant studies had been missed. The Newcastle-Ottawa scale was used to assess the quality of studies.

RESULTS

The findings showed that chronic periodontitis and tooth loss, both individually and in combination, led to an increased risk of mild cognitive decline in adults over 50 years. Within the limitations of this review, periodontitis and tooth loss both contribute to an increased risk of mild cognitive impairment and dementia, but the evidence so far is not strong.

CONCLUSIONS

In future, more robustly designed studies investigating periodontal disease and tooth losslink with cognitive health decline are required with a longer follow-up duration.

Differences in Cumulative Long-Term Care Costs by Dental Visit Pattern Among Japanese Older Adults: The JAGES Cohort Study

BACKGROUND

Long-term care (LTC) costs create burdens on aging societies. Maintaining oral health through dental visits may result in shorter LTC periods, thereby decreasing LTC costs; however, this remains unverified. We examined whether dental visits in the past 6 months were associated with cumulative LTC insurance (LTCI) costs.

METHODS

This cohort study of the Japan Gerontological Evaluation Study targeted independent adults aged≥65 years in 2010 over an 8-year follow-up. We used data from a self-reported questionnaire and LTCI records from the municipalities. The outcome was cumulative LTCI costs, and exposure was dental visits within 6 months for prevention, treatment, and prevention or treatment. A 2-part model was used to estimate the differences in the predicted cumulative LTCI costs and 95% confidence intervals (CIs) for each dental visit.

RESULTS

The mean age of the 8 429 participants was 73.7 years (standard deviation [SD] = 6.0), and 46.1% were men. During the follow-up period, 17.6% started using LTCI services. The mean cumulative LTCI cost was USD 4 877.0 (SD = 19 082.1). The predicted cumulative LTCI costs were lower among those had dental visits than among those who did not. The differences in predicted cumulative LTCI cost were -USD 1 089.9 (95% CI = -1 888.5 to -291.2) for dental preventive visits, -USD 806.7 (95% CI = -1 647.4 to 34.0) for treatment visits, and -USD 980.6 (95% CI = -1 835.7 to -125.5) for preventive or treatment visits.

CONCLUSIONS

Dental visits, particularly preventive visits, were associated with lower cumulative LTCI costs. Maintaining oral health through dental visits may effectively reduce LTCI costs.

A prospective association between social isolation and cognitive performance among older adults in Europe: the role of loneliness and poor oral health

OBJECTIVES

The relationship between social isolation, loneliness, and tooth loss and cognition in older people is poorly understood. We examine how social isolation and cognitive performance are associated prospectively among older adults, as well as how tooth loss and loneliness are related to this association.

METHODS

Using data from 26,168 participants aged ≥50 from the Survey of Health, Ageing and Retirement in Europe (SHARE), we explored the association between social isolation, loneliness, tooth loss and cognition. We used bootstrapping with resampling strategies for testing a moderated mediating model.

RESULTS

Higher social isolation was associated with poorer cognitive performance (B = -0.20, 95% CI = -0.03, -0.01; R2 =0.60), an association mediated by the respondent's number of missing teeth (B = -0.001, 95% CI = -0.002, -0.001). Higher levels of social isolation were associated with a greater number of missing teeth, and a higher number of missing teeth was linked with poorer cognition. We also found that loneliness moderated the relationship between social isolation and both the number of missing teeth (B = -0.11, p  = 0.047) and cognitive performance.

CONCLUSION

In later life, social isolation and loneliness are associated with shoddy oral health and poor cognitive status. Clinicians and policymakers should be aware of both the association between social isolation and feelings of loneliness on dentition and oral health and their relationship to the cognitive status of older adults.

The potential impact of periodontitis on cerebral small vessel disease

Cerebral small vessel disease (CSVD) is a term used to describe abnormalities in the intracranial microvasculature affecting small arteries, arterioles, capillaries, and venules. The etiology of these conditions is not fully understood but inflammation appears to play a significant role. Periodontal diseases have been associated with conditions such as stroke and dementia, which are clinical consequences of CSVD. Periodontitis is a highly prevalent chronic multifactorial inflammatory disease regulated by the host immune response against pathogenic bacterial colonization around the teeth. The inflammatory response and the microbial dysbiosis produce pro-inflammatory cytokines that can reach the brain and promote local changes. This review will explore the potential association between periodontitis and CSVD by assessing the impact of periodontitis-induced inflammation and periodontopathogenic bacteria on the underlying mechanisms leading to CSVD. Given the association of periodontitis with stroke and dementia, which are clinical features of CSVD, it may be possible to suggest a link with CSVD. Current evidence linking periodontitis with neuroimaging findings of CSVD enforces the possible link between these conditions.

Causal relationships involving brain imaging-derived phenotypes based on UKB imaging cohort: a review of Mendelian randomization studies

The UK Biobank (UKB) has the largest adult brain imaging dataset, which encompasses over 40,000 participants. A significant number of Mendelian randomization (MR) studies based on UKB neuroimaging data have been published to validate potential causal relationships identified in observational studies. Relevant articles published before December 2023 were identified following the PRISMA protocol. Included studies (n = 34) revealed that there were causal relationships between various lifestyles, diseases, biomarkers, and brain image-derived phenotypes (BIDPs). In terms of lifestyle habits and environmental factors, there were causal relationships between alcohol consumption, tea intake, coffee consumption, smoking, educational attainment, and certain BIDPs. Additionally, some BIDPs could serve as mediators between leisure/physical inactivity and major depressive disorder. Regarding diseases, BIDPs have been found to have causal relationships not only with Alzheimer's disease, stroke, psychiatric disorders, and migraine, but also with cardiovascular diseases, diabetes, poor oral health, osteoporosis, and ankle sprain. In addition, there were causal relationships between certain biological markers and BIDPs, such as blood pressure, LDL-C, IL-6, telomere length, and more.

Gingipains may be one of the key virulence factors of Porphyromonas gingivalis to impair cognition and enhance blood-brain barrier permeability: An animal study

AIM

Blood-brain barrier (BBB) disorder is one of the early findings in cognitive impairments. We have recently found that Porphyromonas gingivalis bacteraemia can cause cognitive impairment and increased BBB permeability. This study aimed to find out the possible key virulence factors of P. gingivalis contributing to the pathological process.

MATERIALS AND METHODS

C57/BL6 mice were infected with P. gingivalis or gingipains or P. gingivalis lipopolysaccharide (P. gingivalis LPS group) by tail vein injection for 8 weeks. The cognitive behaviour changes in mice, the histopathological changes in the hippocampus and cerebral cortex, the alternations of BBB permeability, and the changes in Mfsd2a and Cav-1 levels were measured. The mechanisms of Ddx3x-induced regulation on Mfsd2a by arginine-specific gingipain A (RgpA) in BMECs were explored.

RESULTS

P. gingivalis and gingipains significantly promoted mice cognitive impairment, pathological changes in the hippocampus and cerebral cortex, increased BBB permeability, inhibited Mfsd2a expression and up-regulated Cav-1 expression. After RgpA stimulation, the permeability of the BBB model in vitro increased, and the Ddx3x/Mfsd2a/Cav-1 regulatory axis was activated.

CONCLUSIONS

Gingipains may be one of the key virulence factors of P. gingivalis to impair cognition and enhance BBB permeability by the Ddx3x/Mfsd2a/Cav-1 axis.

Periodontitis and Outer Retinal Thickness: a Cross-Sectional Analysis of the United Kingdom Biobank Cohort

Purpose

Periodontitis, a ubiquitous severe gum disease affecting the teeth and surrounding alveolar bone, can heighten systemic inflammation. We investigated the association between very severe periodontitis and early biomarkers of age-related macular degeneration (AMD), in individuals with no eye disease.

Design

Cross-sectional analysis of the prospective community-based cohort United Kingdom (UK) Biobank.

Participants

Sixty-seven thousand three hundred eleven UK residents aged 40 to 70 years recruited between 2006 and 2010 underwent retinal imaging.

Methods

Macular-centered OCT images acquired at the baseline visit were segmented for retinal sublayer thicknesses. Very severe periodontitis was ascertained through a touchscreen questionnaire. Linear mixed effects regression modeled the association between very severe periodontitis and retinal sublayer thicknesses, adjusting for age, sex, ethnicity, socioeconomic status, alcohol consumption, smoking status, diabetes mellitus, hypertension, refractive error, and previous cataract surgery.

Main Outcome Measures

Photoreceptor layer (PRL) and retinal pigment epithelium-Bruch's membrane (RPE-BM) thicknesses.

Results

Among 36 897 participants included in the analysis, 1571 (4.3%) reported very severe periodontitis. Affected individuals were older, lived in areas of greater socioeconomic deprivation, and were more likely to be hypertensive, diabetic, and current smokers (all P < 0.001). On average, those with very severe periodontitis were hyperopic (0.05 ± 2.27 diopters) while those unaffected were myopic (-0.29 ± 2.40 diopters, P < 0.001). Following adjusted analysis, very severe periodontitis was associated with thinner PRL (-0.55 μm, 95% confidence interval [CI], -0.97 to -0.12; P = 0.022) but there was no difference in RPE-BM thickness (0.00 μm, 95% CI, -0.12 to 0.13; P = 0.97). The association between PRL thickness and very severe periodontitis was modified by age (P < 0.001). Stratifying individuals by age, thinner PRL was seen among those aged 60 to 69 years with disease (-1.19 μm, 95% CI, -1.85 to -0.53; P < 0.001) but not among those aged < 60 years.

Conclusions

Among those with no known eye disease, very severe periodontitis is statistically associated with a thinner PRL, consistent with incipient AMD. Optimizing oral hygiene may hold additional relevance for people at risk of degenerative retinal disease.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Functional teeth and cognitive function among the Chinese elderly: The chain mediating effect of depressive symptoms and social participation

The objective of this study was to investigate the chain mediating effects of depressive symptoms and social participation between functional teeth and cognitive function based on the biopsychosocial model. Data from the 2018 China Health and Retirement Longitudinal Study were analyzed. The findings revealed a favorable connection between the lack of edentulism and cognitive function, persisting even when accounting for the mediating factors of denture usage, depressive symptoms, and social participation. Furthermore, the study identified six indirect pathways in this relationship. The present study has substantiated the correlation between edentulism and cognitive function, thereby proposing that interventions aimed at denture usage, depressive symptoms, and social participation could potentially serve as preventive measures against cognitive decline in elderly individuals afflicted with edentulism. This underscores the significance of addressing these factors to alleviate cognitive decline.

Assessment of Racial Misclassification Among American Indian and Alaska Native Identity in Cancer Surveillance Data in the United States and Considerations for Oral Health: A Systematic Review

Introduction

Misclassification of American Indian and Alaska Native (AI/AN) peoples exists across various databases in research and clinical practice. Oral health is associated with cancer incidence and survival; however, misclassification adds another layer of complexity to understanding the impact of poor oral health. The objective of this literature review was to systematically evaluate and analyze publications focused on racial misclassification of AI/AN racial identities among cancer surveillance data.

Methods

The PRISMA Statement and the CONSIDER Statement were used for this systematic literature review. Studies involving the racial misclassification of AI/AN identity among cancer surveillance data were screened for eligibility. Data were analyzed in terms of the discussion of racial misclassification, methods to reduce this error, and the reporting of research involving Indigenous peoples.

Results

A total of 66 articles were included with publication years ranging from 1972 to 2022. A total of 55 (83%) of the 66 articles discussed racial misclassification. The most common method of addressing racial misclassification among these articles was linkage with the Indian Health Service or tribal clinic records (45 articles or 82%). The average number of CONSIDER checklist domains was three, with a range of zero to eight domains included. The domain most often identified was Prioritization (60), followed by Governance (47), Methodologies (31), Dissemination (27), Relationships (22), Participation (9), Capacity (9), and Analysis and Findings (8).

Conclusion

To ensure equitable representation of AI/AN communities, and thwart further oppression of minorities, specifically AI/AN peoples, is through accurate data collection and reporting processes.

Hidden dangers: Does multisensory impairments accompanying visual impairment increase dementia risk

BACKGROUND

Growing evidence suggests that sensory impairment, particularly in the form of visual impairment, may contribute to the development of dementia. However, it remains unclear whether experiencing concurrent visual impairment in combination with other types of multisensory impairments may further increase this risk.

METHODS

The study used data from the UK Biobank cohort study, which recruited 500,000 adults. With meticulous screening procedures in place, individuals with visual impairment, hearing impairment, and oral health issues were identified for further follow-up evaluations. A multivariable regression analysis was conducted to investigate the relationship between multisensory impairments concurrent with visual impairment and cognitive function. Cox proportional hazard models were used to estimate hazard ratios and 95% confidence intervals to evaluate the association between multisensory impairments concurrent with visual impairment and dementia risk.

RESULTS

Subjects experiencing multisensory impairments concurrent with visual impairment demonstrated a negative association with cognitive function. Notably, individuals who have both vision and hearing impairments had a significantly higher risk of developing dementia (HR 1.28, 95% CI [1.01-1.63]). Additionally, individuals who experience vision impairment and oral health issues simultaneously were also at higher risk for dementia (HR 1.61, 95% CI [1.32-1.97]). Furthermore, the risk of dementia among individuals with vision impairment, hearing impairment, and oral health issues further escalated to an even higher level (HR 1.63, 95% CI [1.19-2.24]).

CONCLUSIONS

The correlation between the presence of multisensory impairments concurrent with visual impairment and cognitive decline is highly significant. Those with multisensory impairments concurrent with visual impairment are at a significantly increased risk of developing dementia.

Association Between Subjective Masticatory Function and Mild Cognitive Impairment in Older Adults

AIM

This study aimed to examine the effect of subjective masticatory function on the occurrence of mild cognitive impairment (MCI) by analysing the Korean Longitudinal Study of Ageing (KLoSA) data.

METHODS

The study participants were 2954 KLoSA participants aged 60 years or older in the first wave (2006) who had normal cognitive function. The subjective masticatory function was determined using a survey item, and the responses were grouped into 3 categories, ie, good, moderate, and poor. The occurrence of MCI in the 3 groups was followed up until 2020. Cognitive function was assessed based on the Korean Mini-Mental State Examination score. Age, sex, education level, residence, health insurance type, smoking status, drinking status, and the number of chronic diseases were considered as potential confounders. To examine the occurrence of MCI according to subjective masticatory function, Cox proportional hazard regression analysis was performed.

RESULTS

Cox proportional hazard regression models adjusted for confounders yielded the following results: in men, the risk of MCI was higher in those whose subjective masticatory function was moderate and poor, as compared to those with good subjective masticatory function (adjusted hazard ratio [aHR], 1.33; 95% confidence interval [CI], 1.12-1.58; aHR, 1.23; 95% CI, 1.04-1.46). In contrast, in women, subjective masticatory function did not significantly influence the occurrence of MCI (aHR, 1.05; 95% CI, 0.89-1.24; aHR, 1.08; 95% CI, 0.92-1.28).

CONCLUSIONS

This study suggests that poor masticatory function may be a risk factor for MCI in older men.

Sleep Duration and Risk of Periodontitis-A Systematic Review and Meta-Analysis

Periodontitis, with a high prevalence in the whole population, is the main cause of tooth loss. Some studies have revealed that sleep duration may be related to periodontitis, however, the opinions are not consistent. This meta-analysis was carried out to study the potential relationship between sleep duration and periodontitis. A search of relevant articles was conducted on Embase, PubMed, Cochrane Library, and Web of Science. Papers published until the end of November 2022 reporting associations between sleep duration and periodontitis were considered. The pooled odds ratio (OR) with a 95% confidence interval (CI) was calculated to assess the association. Software STATA 14.0 was employed to conduct this analysis. A total of 11 cross-sectional studies were included. Our study showed neither short sleep duration (SSD) nor long sleep duration (LSD) were associated with periodontitis (SSD: OR = 1.04, 95% CI: 0.83, 1.29; LSD: OR = 1.12, 95% CI: 0.94, 1.23), while higher prevalence was observed when sleep duration ≤5 h (OR = 1.41, 95% CI: 1.33, 1.51). In addition, both SSD and LSD were not associated with severe periodontitis (SSD: OR = 0.94, 95% CI: 0.75, 1.16; LSD: OR = 1.19, 95% CI: 0.80, 1.76). In conclusion, the present review indicated that too little sleep duration (≤5 h) significantly increased the risk of periodontitis. However, the evidence is limited due to cross-sectional design of most studies, Hence longitudinal studies should be conducted to support this finding.

Longitudinal association of oral functions and dementia in Japanese older adults

The relationship between oral functions and dementia was examined in 7384 older adults (age ≥ 75 years) who visited a dental clinic in Gifu, Japan. Participants without dementia in a baseline survey in April 2018 were followed until March 2021. As oral functions, chewing function, tongue and lip function, and swallowing function were assessed by self-administered questionnaire, by oral diadochokinesis test, and by repetitive saliva swallowing test, respectively. The presence of systemic diseases was based on data obtained from the National Database of Health Insurance of Japan. At follow-up, 415 (6%) participants were diagnosed with dementia. Multivariate logistic regression analyses showed the presence of dementia at follow-up was associated with female (odds ratio [OR] 1.386; 95% confidence interval [CI] 1.117-1.719), age (OR 1.078; CI 1.056-1.101), regular dental checkups (absence; OR 1.452; CI 1.180-1.788), brushing frequency ≥ twice/day (absence; OR 1.510; CI 1.194-1.911), decayed teeth (presence; OR 1.328; CI 1.071-1.648), swallowing function (poor; OR 1.484; CI 1.135-1.939) at baseline. It was found that poor swallowing function was associated with the future onset of dementia.

Association of Down syndrome with periodontal diseases: Systematic review and meta-analysis

BACKGROUND

Down syndrome (DS) is distinguished by cognitive disability, a concave profile, and systemic complications. Oral diseases have been reported to be common in DS patients.

OBJECTIVE

To investigate the association between DS and periodontal diseases.

METHODS

Two independent reviewers searched six bibliographic databases up to January 2023 and used additional search methods to identify published studies on gingivitis or periodontitis in people with and without DS. Meta-analysis, risk of bias, sensibility analysis, publication bias, and evidence grading were all carried out.

RESULTS

Twenty-six studies were included for analysis. There was a tendency for increased plaque accumulation, periodontal probing, periodontal attachment level, bleeding on probing and indices in DS individuals. Meta-analysis of 11 studies showed a significant association between DS and periodontitis (OR 3.93; 95% CI 1.81-8.53). Probing depth was significantly high in individuals with DS as compared to controls (mean difference 0.40 mm; 95% CI 0.09-0.70). Gingivitis was significantly associated (OR 1.93; 95% CI 1.09-3.41) with DS in four studies. The evidence was classified as 'moderate certainty'.

CONCLUSION

Medium/low-quality studies demonstrate that Down syndrome is strongly associated with periodontitis and moderately associated with gingivitis.

Periodontal and Systemic Diseases: A Descriptive Analysis of Awareness Among the General Saudi Population

Background Taking into account the limited availability of research data, this study aimed to determine the general Saudi population's awareness of the link between periodontal diseases and systemic diseases. Methodology A structured online questionnaire with eight awareness items, apart from demographic variables, was distributed through email, WhatsApp, and Telegram to a sample of 500 individuals. The data were analyzed using a simple descriptive statistical approach and interpreted as ratios for comparison. The awareness regarding systemic diseases associated with periodontal diseases was classified into the following four categories based on the Bloom cutoff points: high (>80%), average (60-79%), low (40-59%), and extremely low (<40%). Results A response rate of 68% was reached with the participation of 340 Saudi citizens residing in the Al Qassim region. Overall, 61.22% of research participants had an average awareness of the link between periodontal and systemic diseases. Almost two-thirds (>60%) of participants were aware that periodontal diseases and systemic diseases have an association and that individuals with systemic diseases need a periodontal checkup. A majority (85%) of participants opined that periodontal treatment has the potential to enhance overall health. Nonetheless, only a few participants (60%) were aware of the association between diabetes mellitus and periodontal diseases, and they had a limited awareness of the association with other systemic diseases. Conclusions Although the Saudi general population possesses average awareness about the relationship between periodontal diseases and systemic diseases, their awareness about different systemic diseases and conditions is extremely low, particularly regarding infertility, stroke, and metabolic diseases. The present research indicates a deficiency in the efforts by healthcare professionals, community service providers, and community administrators to educate the general public regarding the association between periodontal diseases and systemic diseases. This awareness is crucial for individuals to control these intricate, interconnected diseases.

Poor oral health and dementia risk under time-varying confounding: A cohort study based on marginal structural models

BACKGROUND

Bidirectional association between oral health, including tooth loss and oral hypofunction, and cognitive impairment can induce time-varying confounding in association with dementia. This study aimed to investigate the association between oral health and the development of dementia among older adults, considering cognitive impairment as a time-varying confounder.

METHODS

This nine-year follow-up cohort study targeted independent older adults aged ≥65 years who participated in the Japan Gerontological Evaluation Study. The exposure variables were self-reported poor oral health (≤19 remaining teeth, edentulousness, chewing difficulty, swallowing problems, and xerostomia), which were assessed in 2010 and 2013. The outcome variable was the incidence of dementia between 2013 and 2019, which was obtained from the municipalities' administrative database. Furthermore, in 2010 and 2013, we considered cognitive impairment as a time-varying confounder and treated it based on a marginal structural model (MSM), including possible baseline confounders. Oral health and cognitive impairment were assessed using the items of Kihon checklist. We employed a Cox proportional hazards model with a stabilized inverse probability weight and estimated hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

Among 37,556 participants (mean age: 72.8 years [1 SD = 5.5], males: 46.8%), the dementia incidence rate was 2.2/100 person-year. The proportions of those with ≤19 remaining teeth, edentulousness, chewing difficulty, swallowing problems, and xerostomia were 61.3%, 11.0%, 24.4%, 14.7%, and 19.2%, respectively. From the regression analysis based on MSM, ≤19 remaining teeth (HR = 1.12, 95% CI = 1.03-1.23), edentulousness (HR = 1.20, 95% CI = 1.09-1.32), chewing difficulty (HR = 1.11, 95% CI = 1.02-1.21), and xerostomia (HR = 1.10, 95% CI = 1.01-1.20) were significantly associated with an increased risk of dementia; however, swallowing problems were not significantly associated with dementia onset (p > 0.05).

CONCLUSIONS

Even after considering time-varying confounding by cognitive function at baseline and follow-up, we observed significant associations between poor oral health and increased risk of dementia among older adults.

On some challenges of psychological research in late adulthood and aging

The World population is aging and, consequently, understanding late adulthood and aging processes is a major scientific priority. Research in this segment of the life is particularly challenging: the lifespan approach, necessary for thorough aging investigations, implies theoretical multidisciplinary and methodological multivariate perspectives; variability during aging is particularly high compared to previous life phases; study designs must account for specific predicaments (such as confound between age, cohort, and time of measurement; selective study participation and attrition; assumed age-invariance of measurements; retest effects). Furthermore, promising methods for data analysis develop on a daily basis, requiring continuous technical training. I will discuss some of these challenges, summarize extant potential solutions, and touch on some ethical and broader social responsibility issues.

Association of Poor Oral Health With Neuroimaging Markers of White Matter Injury in Middle-Aged Participants in the UK Biobank

BACKGROUND AND OBJECTIVES

Poor oral health is a modifiable risk factor that is associated with clinically observed cardiovascular disease. However, the relationship between oral and brain health is not well understood. We tested the hypothesis that poor oral health is associated with worse neuroimaging brain health profiles in middle-aged persons without stroke or dementia.

METHODS

We performed a 2-stage cross-sectional neuroimaging study using UK Biobank data. First, we tested for association between self-reported poor oral health and MRI neuroimaging markers of brain health. Second, we used Mendelian randomization (MR) analyses to test for association between genetically determined poor oral health and the same neuroimaging markers. Poor oral health was defined as the presence of dentures or loose teeth. As instruments for the MR analysis, we used 116 independent DNA sequence variants linked to increased composite risk of dentures or teeth that are decayed, missing, or filled. Neuroimaging markers of brain health included white matter hyperintensity (WMH) volume and aggregate measures of fractional anisotropy (FA) and mean diffusivity (MD), 2 metrics indicative of white matter tract disintegrity obtained through diffusion tensor imaging across 48 brain regions.

RESULTS

We included 40,175 persons (mean age 55 years, female sex 53%) enrolled from 2006 to 2010, who underwent a dedicated research brain MRI between 2014 and 2016. Among participants, 5,470 (14%) had poor oral health. Poor oral health was associated with a 9% increase in WMH volume (β = 0.09, SD = 0.014, p < 0.001), 10% change in aggregate FA score (β = 0.10, SD = 0.013, p < 0.001), and 5% change in aggregate MD score (β = 0.05, SD = 0.013, p < 0.001). Genetically determined poor oral health was associated with a 30% increase in WMH volume (β = 0.30, SD = 0.06, p < 0.001), 43% change in aggregate FA score (β = 0.43, SD = 0.06, p < 0.001), and 10% change in aggregate MD score (β = 0.10, SD = 0.03, p < 0.01).

DISCUSSION

Among middle age Britons without stroke or dementia, poor oral health was associated with worse neuroimaging brain health profiles. Genetic analyses confirmed these associations, supporting a potentially causal association. Because the neuroimaging markers evaluated in this study precede and are established risk factors of stroke and dementia, our results suggest that oral health, an easily modifiable process, may be a promising target for very early interventions focused on improving brain health.

Oral Health and Brain Health: Cause, Consequence, or Confounding?

Epidemiologic studies of the association between periodontal disease and cardiovascular disease, including stroke, had mixed findings.1 Some studies have found that serum antibodies to major periodontal pathogens are associated with coronary heart disease (CHD), suggesting that periodontal infection or the host response to periodontal infection may play a causal role in CHD.1 More recently, longitudinal studies have supported an association of periodontal disease between cognitive decline and dementia.2 The motivation for these studies has been two-fold. First, periodontal disease is known to be associated with systemic inflammation,3 which, in turn, is known to be causally associated with atherosclerotic disease.4 Second, periodontal disease is potentially modifiable in the population. The limitation of all observational epidemiologic studies is the problem of confounding by incompletely measured or unmeasured variables, such as diet, health behaviors including oral hygiene, and the host response to infection. In addition, studies oral health and either cognitive decline or dementia may suffer from reverse causality; cognitive changes may lead to lessened oral hygiene and periodontal disease.

Brain Health and Cognition in Older Adults: Roadmap and Milestones towards the Implementation of Preventive Strategies

In this narrative review, we delve into the evolving concept of brain health, as recognized by the WHO, focusing on its intersection with cognitive decline. We emphasize the imperative need for preventive strategies, particularly in older adults. We describe the target population that might benefit the most from risk-based approaches-namely, people with subjective cognitive decline. Additionally, we consider universal prevention in cognitively unimpaired middle-aged and older adults. Delving into multidomain personalized preventive strategies, we report on empirical evidence surrounding modifiable risk factors and interventions crucial in mitigating cognitive decline. Next, we highlight the emergence of brain health services (BHS). We explain their proposed role in risk assessment, risk communication, and tailored interventions to reduce the risk of dementia. Commenting on ongoing BHS pilot experiences, we present the inception and framework of our own BHS in Monza, Italy, outlining its operational structure and care pathways. We emphasize the need for global collaboration and intensified research efforts to address the intricate determinants of brain health and their potential impact on healthcare systems worldwide.

An umbrella review on the association between factors of oral health and cognitive dysfunction

An increasing number of systematic reviews and meta-analyses have been published on the association between oral health and cognitive dysfunction, also known as oral-cognitive links. However, there is great diversity in the oral and cognitive factors included in these studies, with different opinions for clinical practice drawn from the evidence. To understand which oral and cognitive factors are involved in those associations, we conducted an umbrella review of 28 systematic reviews, including 12 meta-analyses, on oral-cognitive links. We found that (a) periodontal diseases, oral microbiome, and dementia were frequently studied, while other factors, such as mastication and mild cognitive impairment, were less commonly investigated, and (b) severe deterioration of oral health, such as severe periodontitis or extensive tooth loss, rather than the presence of oral diseases alone, was strongly associated with cognitive dysfunction. In conclusion, the diversity of oral and cognitive factors included in the review studies reflects the complexity of oral-cognitive links. Clarifying the factors helps to form evidence-based clinical advice for healthcare.

Age-group-specific association of oral health and systemic health on cognitive function: a cross-sectional study of Korean elders

BACKGROUND

Although the importance of oral and systemic healthcare for elderly people is increasing owing to the rapid ageing of the population in South Korea, studies on the relationship between oral health, systemic health, and cognitive function, as well as on the prediction of cognitive function by oral and systemic health depending upon age groups are lacking.

METHODS

We included 5,975 out of 6,488 participants from the 8th wave of the Korean Longitudinal Study of Aging (KLoSA) panel data, divided the participants into three age groups, and performed a hierarchical multiple linear regression analysis to explain cognitive function with four types of predictors: oral health status, sociodemographic factors, objective health status, and subjective health status.

RESULTS

Oral health status was positively correlated with systemic health status and cognitive function. Of all ages over 54, cognitive function was significantly predicted by oral health variables, such as the number of functional teeth, masticatory ability, and Geriatric Oral Health Assessment Index (GOHAI); sociodemographic variables, such as age, sex, education level, and residence; and systemic health variables, such as diagnosis of diabetes mellitus, cancer or malignant tumours, cerebrovascular disease and rheumatoid arthritis, depressive symptom, and self-rated health status. Oral health variables explained cognitive function differently by age group; GOHAI appeared important predictor in the group aged < 75 years, whereas the number of functional teeth did in the group aged ≥ 75 years. Educational level, masticatory ability, depressive symptoms, and self-rated health status were pivotal factors age-independently.

CONCLUSIONS

The general and age-group-specific association between oral health, systemic health, and cognitive function were confirmed, suggesting that age-group-specific oral healthcare should be emphasized for the effective management of systemic and cognitive health in the elderly group.

Poor Oral Health Linked with Higher Risk of Alzheimer's Disease

Alzheimer's disease (AD) is a multifactorial neurodegenerative disease characterized by cognitive and behavioral changes in older adults. Emerging evidence suggests poor oral health is associated with AD, but there is a lack of large-scale clinical studies demonstrating this link. Herein, we used the TriNetX database to generate clinical cohorts and assess the risk of AD and survival among >30 million de-identified subjects with normal oral health (n = 31,418,814) and poor oral health (n = 1,232,751). There was a greater than two-fold increase in AD risk in the poor oral health cohort compared to the normal oral health group (risk ratio (RR): 2.363, (95% confidence interval: 2.326, 2.401)). To reduce potential bias, we performed retrospective propensity score matching for age, gender, and multiple laboratory measures. After matching, the cohorts had no significant differences in survival probability. Furthermore, when comparing multiple oral conditions, diseases related to tooth loss were the most significant risk factor for AD (RR: 3.186, (95% CI: 3.007, 3.376)). Our results suggest that oral health may be important in AD risk, regardless of age, gender, or laboratory measures. However, more large-scale cohort studies are necessary to validate these findings and further evaluate links between oral health and AD.

Accuracy of periodontitis diagnosis obtained using multiple molecular biomarkers in oral fluids: A systematic review and meta-analysis

AIM

To determine the accuracy of biomarker combinations in gingival crevicular fluid (GCF) and saliva through meta-analysis to diagnose periodontitis in systemically healthy subjects.

METHODS

Studies on combining two or more biomarkers providing a binary classification table, sensitivity/specificity values or group sizes in subjects diagnosed with periodontitis were included. The search was performed in August 2022 through PUBMED, EMBASE, Cochrane, LILACS, SCOPUS and Web of Science. The methodological quality of the articles selected was evaluated using the QUADAS-2 checklist. Hierarchical summary receiver operating characteristic modelling was employed to perform the meta-analyses (CRD42020175021).

RESULTS

Twenty-one combinations in GCF and 47 in saliva were evaluated. Meta-analyses were possible for six salivary combinations (median sensitivity/specificity values): IL-6 with MMP-8 (86.2%/80.5%); IL-1β with IL-6 (83.0%/83.7%); IL-1β with MMP-8 (82.7%/80.8%); MIP-1α with MMP-8 (71.0%/75.6%); IL-1β, IL-6 and MMP-8 (81.8%/84.3%); and IL-1β, IL-6, MIP-1α and MMP-8 (76.6%/79.7%).

CONCLUSIONS

Two-biomarker combinations in oral fluids show high diagnostic accuracy for periodontitis, which is not substantially improved by incorporating more biomarkers. In saliva, the dual combinations of IL-1β, IL-6 and MMP-8 have an excellent ability to detect periodontitis and a good capacity to detect non-periodontitis. Because of the limited number of biomarker combinations evaluated, further research is required to corroborate these observations.

Oral health, stress and barriers accessing dental health care among war-affected Ukrainian refugees in Germany

BACKGROUND

After Russian invasion many Ukrainians fled to European countries including Germany. In this context, the German health care system faced challenges delivering dental care to a displaced population. Recently surfaced obstacles as well as different cultural and medical traits need to be considered in order to deliver appropriate medical care. The aim of this study was to evaluate oral health and hygiene of Ukrainian refugees, identify barriers accessing dental health care and explore the relation to their mental health state.

METHODS

This cross-sectional study was conducted using a self-assessment questionnaire, distributed via non-probability snowball sampling method among war-affected Ukrainians, who fled to Germany. The online form was distributed via web-based platforms, the printed version was hand-delivered across diverse local venues. Chi-Square Tests, T-Tests and Mann-Whitney-U Tests were performed. Analysis of variance and Spearman correlation coefficient analysis were also conducted.

RESULTS

From 819 completed questionnaires, 724 questionnaires were included in the analysis with 78 males (10.8%) and 640 females (88.6%) and a mean age of 37.5 years (SD = 10.5). The majority of participants rated their state of teeth (77%) and gums (81%) as average or better. The main problems, caused by state of their teeth, were: "Have avoided smiling because of teeth" (23.6%) or "Felt embarrassed due to appearance of teeth" (22.2%). The most frequent limiting factors to access dental care were finances (82.6%), language (82.2%) and complicated health care system (74.1%). 45.8% of the participants scored 10 or more in the Patient Health Questionnaire and 37.4% in the Generalized Anxiety Disorder 7-item scale, respectively. These participants were more likely to report pain, poor state of teeth and gums and to fail a dental consultation. Overall, 59.6% participants reported not consulting a dentist, when needed. Failed consultations were associated with a poorer reported state of teeth and gums.

CONCLUSIONS

Ukrainian refugees reported barriers accessing dental health care in Germany. It is important to improve oral health literacy and dental services for displaced people and provide help and guidance in seeking dental care.

The impact of aromatherapy-based oral care on oral conditions, salivary pH, and halitosis in older adults with dementia: Pilot study

Inadequate oral care and poor oral health in older adults are known to increase the risk of dementia. Dementia patients residing in long-term care facilities are especially vulnerable to oral diseases due to their care-resistant behavior. This study aimed to investigate the effects of a 7-day oral care program based on an aroma solution in 58 dementia patients (29 each in the experimental and control groups) admitted to a long-term care hospital in South Korea. The experimental group received oral care with a solution containing peppermint, tea tree, and lemon essential oils, and the control group with a saline solution. The effectiveness of oral care was assessed by the participants' oral condition, salivary pH, and halitosis. The experimental group showed significant improvements (P<.001) in all three outcomes, indicating that oral care with an aroma solution can improve the oral health of older dementia patients residing in long-term care facilities.

Investigating the relationship between periodontitis and specific memory processes in the search for cognitive markers of Alzheimer's disease risk

The spontaneous retrieval deficit (SRD) hypothesis argues that individuals in the preclinical stages of Alzheimer's disease (AD) are particularly impaired in spontaneous retrieval, which manifests in reduced mind-wandering. Our main purpose was to provide novel evidence to support the SRD hypothesis by investigating, for the first time, the relationship between mind-wandering and periodontitis, the latter being the risk factor for AD. The second objective was to address the lack of deeper understanding of the relationship between oral health and specific cognitive abilities by investigating whether periodontitis would be primarily associated with memory. Sixty community-dwelling dementia-free older adults completed neuropsychological tests that focused on various cognitive abilities and a computerised task, during which mind-wandering was evaluated. Periodontal health was assessed subjectively, and through an oral examination by a qualified dentist that focused on visible periodontitis-related changes in gingival tissues and the number of periodontitis bacteria. In line with our predictions, objective and subjective symptoms of poorer periodontal health were associated with less mind-wandering, providing further support for the SRD hypothesis. Again in line with predictions, poorer periodontal health was associated with worse episodic memory, with no relationship between periodontitis and the measure targeting various cognitive abilities, from which memory was excluded.