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.

Serum levels of vitamin D and periodontal inflammation in community-dwelling older Japanese adults: The Otassha Study.

AIM: To evaluate the association between vitamin D status and periodontal inflammation as determined by the periodontal inflamed surface area (PISA) in community-dwelling older adults. MATERIALS AND METHODS: This cross-sectional study included 467 Japanese adults (mean age = 73.1 years) who underwent full-mouth periodontal examinations and measurements of serum levels of 25-hydroxyvitamin D (25(OH)D). We used linear regression and restricted cubic spline models to analyse the association between exposure (serum 25(OH)D) and outcome (PISA). RESULTS: The linear regression model showed that, after adjusting for potential confounders, participants in the lowest quartile of serum 25(OH)D had 41.0 mm2 more PISA (95% confidence interval [CI]: 4.6-77.5) than the reference group (the highest quartile of serum 25(OH)D). The spline model showed that the association between serum 25(OH)D and PISA was non-linear and restricted to the low 25(OH)D range. PISA initially sharply decreased as serum 25(OH)D increased, and then the decreasing trend slowed and plateaued. The inflection point with the minimum PISA value was a serum 25(OH)D level of 27.1 ng/mL, above which there was no decreasing trend in PISA with increasing serum 25(OH)D levels. CONCLUSIONS: Low vitamin D status had an L-shaped association with periodontal inflammation in this cohort of Japanese adults.

The effect of multimodal comprehensive care methodology training on oral health care professionals' empathy for patients with dementia.

BACKGROUND: The prevalence of oral diseases in people with dementia has increased, and patients with dementia have worse oral health than people without dementia. However, in the provision of oral care, these patients often exhibit care-resistant behaviours. Empathy is important for health care professionals who provide dental care for people with dementia. A study was conducted to assess whether a multimodal comprehensive care methodology training programme, Humanitude™, was associated with an improvement in empathy for people with dementia among oral health care professionals. METHODS: This research was a pre-post prospective study. A total of 45 dentists and dental hygienists participated in a 7-h multimodal comprehensive care methodology training programme. Participants' empathy for their patients was evaluated with the Jefferson Scale of Physician Empathy-Health Professionals Version (JSPE-HP) before the training and 1 month after the training (primary outcome). Each participant listed 3 patients with poor oral health due to the refusal of usual oral care or dental treatment from his or her clinical practice. The oral health of the 3 care-resistant patients listed by each participant was evaluated by the Oral Health Assessment Tool (OHAT) before the training and 1 month after the training (secondary outcome). RESULTS: The post-training response rate was 87% (21 dentists and 18 dental hygienists). From pre-training to post-training, the multimodal comprehensive care methodology training significantly increased the mean empathy score (from 113.97 to 122.95, P < 0.05, effect size = 0.9). Regardless of gender, profession and years of clinical experience, all post-training subgroup scores were higher than the pre-training subgroup scores. The tongue, natural teeth, and oral hygiene scores of patients with dementia who resisted usual oral care or dental treatment, as assessed by the OHAT, were significantly improved compared with those before the training. CONCLUSIONS: The multimodal comprehensive care methodology training was associated with an improvement in oral health professionals' empathy for patients with dementia. These findings suggest that randomized controlled trials with large sample sizes will be needed. TRIAL REGISTRATION: UMIN Clinical Trials Registry (UMIN-CTR), UMIN000041687 . Registered 4 September 2020 - Retrospectively registered, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000047586.

Qualitative analysis of the vocabulary used in work logs of a preventive programme for elderly oral function and nutrition.

BACKGROUND: In Japan, day care services for elders include programmes aimed at improving nutrition and oral and motor functions. Few studies have qualitatively assessed these interventions. OBJECTIVE: To qualitatively search for the characteristic words used in the work logs of a preventive programme on oral function and nutrition for elders by intervention period and intervention type． METHODS: We included 83 participants (81.3 ± 8.2 years) from four day care services in Japan and divided them into the following groups randomly: those who received oral function intervention only, nutritional intervention only and those who received combined oral function plus nutritional intervention. The interventions were conducted twice per month for 24 months. Data from handwritten work logs were entered into a computer as text files. Monitoring of frequently appearing words, co-occurrence analysis and cross-tabulation by intervention period and intervention types was conducted using text mining analysis. RESULTS: Correspondence analysis revealed that the words used during 1-6 months and 7-12 months were similar in participants' subjective content, and those used in objective content in 13-18 months and 19-24 months were similar. These results indicate that subjective improvements increased after 13 months, and it was maintained within 24 months. The combined intervention type is ideal for oral and nutrition problems. CONCLUSION: Because this text mining approach revealed the changes in the words used and could be used to monitor any subjective improvement, this approach may help evaluate the effects of preventive care.

Feasibility of Oral Function Evaluation According to Dementia Severity in Older Adults with Alzheimer's Disease.

Oral function evaluation in older adults with dementia is important for determining appropriate and practical dietary support plans; however, it can be challenging due to their difficulties in comprehending instructions and cooperating during assessments. The feasibility of oral function evaluation has not been well studied. This cross-sectional study aimed to determine the feasibility of oral function evaluation in older adults with Alzheimer's disease (AD) according to Functional Assessment Staging of Alzheimer's Disease (FAST) stages. In total, 428 older adults with AD (45 men and 383 women; mean age: 87.2 ± 6.2 years) were included. Multilevel logistic regression models were used to examine the prevalence of participants who were unable to perform oral function evaluations, including oral diadochokinesis (ODK), repeated saliva swallow test (RSST), and modified water swallow test (MWST). In comparison to the reference category (combined FAST stage 1-3), FAST stage 7 was associated with the infeasibility of ODK (adjusted odds ratio, 95% confidence interval = 26.7, 4.2-168.6), RSST (5.9, 2.2-16.1), and MWST (8.7, 1.6-48.5, respectively). Oral function evaluation is difficult in older adults with severe AD. Simpler and more practical swallowing function assessments and indicators that can be routinely observed are required.

Association between Dementia Severity and Oral Hygiene Management Issues in Older Adults with Alzheimer's Disease: A Cross-Sectional Study.

Oral hygiene management issues vary across types and clinical stages of dementia. We aimed to clarify the issues related to oral hygiene management in older adults with Alzheimer's disease (AD) according to stages defined by the Functional Assessment Staging of Alzheimer's Disease (FAST). In all, 397 records (45 men and 352 women; average age, 86.8 years; age range, 65-106) from older adults with AD were used for the cross-sectional study. We used data from a cohort of older adults (≥65 years old) who required long-term care and lived in the Omorimachi area of Yokote City, Akita Prefecture, Japan. Multilevel logistic regression analysis was conducted to examine the associations of the FAST stage, set as the exposure variable, with oral hygiene management parameters set as outcome variables. Compared to the reference category (combined FAST stage 1-3), FAST stages 6 and 7 had significantly higher odds ratios for refusal of oral health care, dependence in performing oral health care, and rinsing and gargling disability. FAST stages 4 and 7 were associated with dental plaque accumulation. Oral health care for older adults with AD should be planned appropriately according to dementia severity.

Severity of Dementia Is Associated with Increased Periodontal Inflamed Surface Area: Home Visit Survey of People with Cognitive Decline Living in the Community.

No studies have measured the periodontal inflamed surface area in people with dementia, although periodontal disease is a major health issue in this group. This study aimed to determine the relationship between dementia severity and periodontal inflamed surface area. An interdisciplinary team, including a dentist and psychiatrist, conducted an in-home survey of older people living in the community. This cross-sectional study was designed as part of a larger cohort study. The interdisciplinary team visited 198 individuals with cognitive decline. We surveyed the clinical dementia rating, periodontal inflamed surface area, number of teeth, and other health issues. We used multiple linear regression analysis to assess the 75 people who were able to take part in all the visits. Number of teeth (Beta = 0.479, p < 0.001), clinical dementia rating (Beta = 0.258, p = 0.013), and age (Beta = 0.250, p = 0.017) were independently associated with periodontal inflamed surface area after adjusting for biological sex, depression, diabetes, collagen disease, visual disorder, and osteoporosis medication. To make communities more dementia-friendly, we must protect older people with dementia from developing poor oral health, which may require home visits for dental assessment.

A comparison of colorimetric and visual methods for the assessment of masticatory performance with color-changeable chewing gum in older persons.

BACKGROUND/PURPOSE: Color-changeable chewing gum is used for the evaluation of masticatory performance. However, it is currently unclear whether colorimetric and visual assessment methods yield consistent results. This study aimed to clarify the consistency between colorimetric and visual methods used for the evaluation of color changes in color-changeable chewing gum. MATERIALS AND METHODS: The sample comprised 644 older persons (mean age, 75.4 ± 6.4 years). The chewing gum was masticated 60 times at the participant's own chewing rate and then expectorated. The color of the chewing gum was evaluated with the ΔE values and a∗ values, measured using a colorimeter, and the 10 Color Shades (10CSh) and 5 Color Scales (5CSc), using visual evaluation. Spearman's correlation analysis was performed to examine the correlation between the results obtained by the four methods. The significance level was set at α = 0.05. RESULTS: The ΔE values, a∗ values, 10CSh scores, and 5CSc scores were all significantly correlated. The highest correlation coefficient (0.979) was between the ΔE values and a∗ values. The lowest correlation coefficient (0.847) was between the a∗ values and 5CSc scores. Decreased masticatory performance was observed with increased age. CONCLUSION: Significant correlations were found for all four methods used in the assessment of masticatory performance with color-changeable chewing gum. While visually based assessments are valid, colorimetric methods are more sensitive to smaller changes in masticatory performance.

Oral frailty and gait performance in community-dwelling older adults: findings from the Takashimadaira study.

Purpose This cross-sectional study compared gait performance between community-dwelling older adults with and without accumulated deficits in oral health, defined as oral frailty.Methods A total of 1,082 individuals (439 men and 643 women; mean age, 77.1 years) from the Takashimadaira study were included in the current analysis. Based on a multifaceted oral health assessment, oral frailty was defined as having three or more of the following six components: (i) fewer teeth, (ii) low masticatory performance, (iii) low articulatory oral motor skills, (iv) low tongue pressure, (v) difficulties in eating, and (vi) swallowing. Eight gait parameters were assessed using an electronic walkway. Gait characteristics comparison between groups with and without oral frailty was performed using multiple linear regression models. Models were adjusted for age, sex, educational status, income, smoking, drinking, physical activity level, height, body mass index, comorbidities, and the presence of chronic pain.Results Oral frailty was observed in 227 (21.0%) participants. After adjusting for potential confounders, the participants with oral frailty had slower gait speed, shorter stride and step length, wider step width, and longer double support duration as well as higher variability of stride length and step length.Conclusions Oral frailty was associated with poor gait performance among community-dwelling older adults.

Association of eating alone with oral frailty among community-dwelling older adults in Japan.

BACKGROUND: Because the oral cavity plays an important role as the first digestive organ, thus, decreased oral function such as oral frailty may negatively affect the nutritional status of older adults. However, few studies have examined the relationship between oral frailty and dietary habits. OBJECTIVE: This cross-sectional study aimed to investigate the relationship between oral functions and dietary habits in a general population of older adults. METHODS: Participants were 722 older adults (mean age, 79.1 ± 4.5 [standard deviation] years) who had participated in the Takashimadaira Study conducted in 2018, in Tokyo, Japan. Oral frailty among them was determined by a modified version of a well-known method originally proposed by other researchers. Dietary habits were evaluated based on two aspects: dietary variety and eating behavior (eating alone or together). The independent association between oral frailty and dietary habits was analyzed with an ordinal logistic regression model, controlling for important covariates. RESULTS: Of the participants, 23.5 %, 57.2 % and 19.3 % were determined to have non-oral frailty, pre-oral frailty, and oral frailty, respectively. Eating alone (practiced by 36.0 % of the participants) was significantly associated with oral frailty status (adjusted odds ratio, 1.82 [95 % confidence interval, 1.14-2.90]) even after controlling for potential confounders including age, sex, body mass index, living arrangement, employment, chronic medical conditions, and depressive mood. CONCLUSIONS: We found a significant association between eating alone and oral frailty in a general population of Japanese older adults. Because of the strong association, further investigation of potential mechanisms is warranted.

Association between decrease in frequency of going out and oral function in older adults living in major urban areas.

AIM: To examine the association between a decrease in the frequency of going out and oral function in independent older adults living in the urban area of Tokyo. METHODS: The participants analyzed were 785 older adults from the "Takashimadaira Study" (344 men and 441 women, age 77.0 ± 4.6 years). This study investigated the following items: decrease in frequency of going out; basic characteristics (sex, age); physical factors, such as oral function (difficulty chewing, difficulty swallowing, dry mouth); body pain; the Japan Science and Technology Agency Index of Competence; physical activities; psychological factors, such as the Geriatric Depression Scale-15 score; and social and environmental factors, such as the presence or absence of participation in organization activities. RESULTS: To investigate the factors associated with a decrease in frequency of going out, logistic regression analysis showed an association with age (OR 1.08, 95% CI 1.03-1.13), difficulty chewing (OR 2.41, 95% CI 1.52-3.83), dry mouth (OR 1.68, 95% CI 1.07-2.64), body pain (OR 1.78, 95% CI 1.14-2.78), Japan Science and Technology Agency Index of Competence scores (OR 0.91, 95% CI 0.84-0.99), physical activities (OR 0.99, 95% CI 0.98-1.00), Geriatric Depression Scale-15 scores (OR 1.13, 95% CI 1.05-1.21) and organization activities (OR 1.94, 95% CI 1.22-3.07). Covariance structural analyses showed that both "difficulty chewing" and "dry mouth" significantly affected "decrease in frequency of going out." In addition, decrease in frequency of going out was significantly affected by " Geriatric Depression Scale-15 scores" through oral function. CONCLUSIONS: The relationship between oral function and decrease in frequency of going out was clarified, after the multifaceted factors were adjusted. Geriatr Gerontol Int 2019; 19: 792-797.

Frequency of CTLA-4 gene CT60 polymorphism may not be affected by vitamin D receptor gene Bsm I polymorphism or HLA DR9 in autoimmune-related type 1 diabetes in the Japanese.

One of the CTLA-4 SNPs, +6230G>A (CT60), has recently been reported to be related to susceptibility to type 1 diabetes and autoimmune thyroid disease. We have previously reported an association between acute-onset type 1 diabetes in Japanese and the Vitamin D receptor (VDR) gene Bsm I large B polymorphism, which is related to the Th1-type response. Moreover, we found a significant correlation between autoimmune-related type 1 diabetes with HLA DR9 and detection of GAD-reactive Th1 (T helper 1)-type cells. In the present article, we tried to clarify whether the frequency of one of the CTLA-4 SNPs, +6230G>A (CT60), is affected by the VDR gene Bsm I polymorphism or by HLA DR9 in Japanese type 1 diabetics. The frequency of the CT60 GG genotype did not appear to be affected by either the VDR gene Bsm I large B polymorphism or HLA DR9.

Relation between development of nephropathy and the p22phox C242T and receptor for advanced glycation end product G1704T gene polymorphisms in type 2 diabetic patients.

OBJECTIVE: The development of diabetic nephropathy is considered to be associated with oxidative stress. NADPH oxidase and the receptor for advanced glycation end products (RAGE) have attracted attention as mechanisms of generating oxidative stress. We studied the relation between the genotypes of the NADPH p22phox C242T and RAGE G1704T polymorphisms and the development of diabetic nephropathy in type 2 diabetic patients. RESEARCH DESIGN AND METHODS: Using a retrospective review of clinical data, we allocated 181 Japanese type 2 diabetic patients to one of two groups: patients without diabetic nephropathy (group N; n = 108) and patients developing diabetic nephropathy (group D; n = 73) for 10 years or more. The p22phox C242T and RAGE G1704T polymorphisms were examined by Taqman PCR methods. RESULTS: The frequency of the p22phox CC genotype was significantly higher in group D than in group N (90 vs. 79%; P = 0.0427). The frequency of the RAGE GT + TT genotype was significantly higher in group D than in group N (26 vs. 13%; P = 0.0313). The frequency of the combination of p22phox CC and RAGE GT + TT genotypes was significantly higher in group D than in group N (22 vs. 8%; P = 0.0057). In multiple logistic regression analysis, systolic blood pressure, HbA(1c), triglycerides, and the combination of polymorphisms were shown to be independent variables. CONCLUSIONS: These results suggest that assessment of the combination of NADPH p22phox C242T and RAGE G1704T polymorphisms may be useful in identifying the risk for developing diabetic nephropathy in type 2 diabetic patients.

High frequency of valpha24(+) vbeta11(+) T-cells observed in type 1 diabetes.

OBJECTIVE: Natural killer T-cells (NKT cells) are believed to play an important role in the regulation of immune response, and a numerical and functional deficit of NKT cells has been reported to be associated with the pathogenesis of autoimmune diseases. Thus far, it has been shown that subjects with type 1 diabetes have a lower frequency of NKT cells than nondiabetic subjects. In this study, we measured the frequency of peripheral Valpha24(+) Vbeta11(+) T-cells, which include human NKT cells, in Japanese diabetic patients. RESEARCH DESIGN AND METHODS: Peripheral blood samples were obtained from 164 Japanese diabetic patients and 67 healthy subjects. The diabetic patients were classified into four categories as follows: islet-associated autoantibody-positive (Ab(+)) and -negative (Ab(-)) classic type 1 diabetes, latent autoimmune diabetes in adults (LADA), and type 2 diabetes. We measured the frequency of peripheral Valpha24(+) Vbeta11(+) CD3(+) triple-positive cells. RESULTS: Unexpectedly, a higher frequency of Valpha24(+) Vbeta11(+) T-cells was observed in Ab(+) and Ab(-) patients compared with LADA patients (P = 0.0294 and P = 0.0021), type 2 diabetic patients (P < 0.0001 and P < 0.0001), and healthy subjects (P = 0.0046 and P = 0.0001). Moreover, an inverse correlation between Valpha24(+) Vbeta11(+) T-cell frequency and disease duration was observed in Ab(+) (rho = -0.455; P = 0.0023) and Ab(-) (rho = -0.432; P = 0.0162) patients. CONCLUSIONS: Our findings indicate that a high frequency of Valpha24(+) Vbeta11(+) T-cells is a unique finding in recent-onset classic type 1 diabetes, and measurement of Valpha24(+) Vbeta11(+) T-cell frequency may be useful to assess the disease activity of classic type 1 diabetes.

Vitamin D receptor gene polymorphism affects onset pattern of type 1 diabetes.

Type 1 diabetes mellitus is recognized as a T-cell-mediated autoimmune disease. Vitamin D compounds are known to suppress T-cell activation by binding to the vitamin D receptor (VDR); and thus, VDR gene polymorphisms may be related to T-cell-mediated autoimmune diseases. We, therefore, investigated a VDR gene polymorphism in type 1 diabetes. We examined the VDR gene Bsm I polymorphism in 203 type 1 diabetic patients and 222 controls, and the association between the VDR gene polymorphism and type 1 diabetes and their onset pattern. We found a significantly higher frequency of B allele in type 1 diabetics overall, compared with controls (P = 0.0010). Moreover, there was a significant difference in B-allele frequency between acute-onset type 1 diabetics and controls (P = 0.0002), whereas this difference was not observed between slow-onset type 1 diabetics and controls. Regardless of the existence of islet-associated autoantibody, we found a significant difference in B-allele frequency between acute-onset type 1 diabetics and controls. In conclusion, we found an association between a VDR gene polymorphism and acute-onset type 1 diabetes. Assessment of this VDR gene polymorphism may contribute to prediction of the onset pattern in individuals with a high risk of type 1 diabetes.

Nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase) P22 Phox C242T gene polymorphism in type 1 diabetes.

Type 1 diabetes is caused by the immune-mediated destruction of insulin-secreting pancreatic beta cells and is thought to be an autoimmune disease resulting from a complex interaction of genetic and environmental factors. In animal models of type 1 diabetes, macrophages and their products, superoxides, have central roles in the beta cell destruction, but in humans their roles remain unclear. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase produces superoxide in macrophages, and its essential component, p22 phox, is a critical enzyme for superoxide production. The C242T polymorphism in the p22 phox coding gene has been reported to be associated with reduced oxidase activity. We therefore investigated whether the p22 phox gene polymorphism affected the susceptibility to and clinical course of type 1 diabetes. We examined 287 Japanese type 1 diabetic patients and 425 unrelated nondiabetic subjects. In addition, we allocated the diabetic patients to the following three groups: (1) acute-onset type 1 diabetes with at least one autoantibody (GADA, IA-2, IAA); (2) acute-onset type 1 diabetes without autoantibodies; and (3) slow-onset type 1 diabetes with autoantibody. We could not find a significant difference in p22 phox genotype and T allele frequency between overall type 1 diabetic patients and control subjects. Regardless of the onset pattern and autoantibody positivity of type 1 diabetes, no difference in p22 phox genotype and T allele frequency was found among the groups. In conclusion, the p22 phox C242T gene polymorphism did not affect the susceptibility to and clinical course of Japanese type 1 diabetes.

NKT cell frequency in Japanese type 1 diabetes.

A numerical and functional deficit of natural killer T (NKT) cells has been reported to be associated with the pathogenesis of Caucasian patients with type 1 diabetes. However, a conflicting finding of a higher frequency of NKT cells (Valpha24+ Vbeta11+ T cells) was observed in islet-associated Ab+ and Ab- Japanese "classic" type 1 diabetes. Here, we combined the data of NKT cell frequency in Ab+ and Ab- "classic" type 1 diabetic patients and then analyzed the relationship between NKT cell frequency and disease activity.

GAD-reactive T cells were mainly detected in autoimmune-related type 1 diabetic patients with HLA DR9.

Type 1 diabetes mellitus (T1DM) is considered to be a T cell-mediated disease, and many reports suggest that some HLA types, especially HLA DR4 and DR9, convey susceptibility to T1DM in Japanese. We investigated the association between T cell reactivity against GAD and HLA types in "islet-associated autoantibody-positive" T1DM in Japanese. Blood samples were obtained from 36 "autoantibody-positive" type 1 diabetic patients with HLA DR4 or DR9 and 23 type 2 diabetic patients with HLA DR4 or DR9 as controls. They were divided into three groups, DR4/9, DR4/X, and DR9/X groups. In each HLA type group, GAD-reactive IFN-gamma-producing CD4(+) cells were assessed by means of intracellular cytokine staining for flow cytometry. Type 1 diabetic patients with HLA DR9/X had significantly higher numbers of GAD-reactive IFN-gamma-producing CD4(+) cells as compared to type 1 diabetic patients with DR4/X or DR4/9 (P < 0.05) and all type 2 diabetic patients. There was no significant difference in the number of GAD-reactive IFN-gamma-producing CD4(+) cells between type 1 diabetic and type 2 diabetic patients belonging to the DR4/X and DR4/9 groups. There was an association between T cell reactivity against GAD and HLA DR9 in Japanese type 1 diabetes.