Dental prosthesis use moderates association between tooth loss and risk of depressive symptoms in older adults with severe tooth loss: The JAGES cohort trial.

PURPOSE: Depression is a leading cause of disability. Although tooth loss increases the risk of depressive symptoms, it is unclear whether dental prosthesis use moderates this risk. This study aimed to investigate whether dental prosthesis use moderates the association between tooth loss and new depressive symptoms in older adults. METHODS: This cohort study used data from the 2016 and 2019 Japan Gerontological Evaluation Study (JAGES). The participants were independent older adults aged ≥65 years without depressive symptoms in 2016. The onset of depressive symptoms in 2019 was the outcome variable. The explanatory variables were dental status (≥20 teeth, 10-19 teeth with or without dental prostheses, and 0-9 teeth with or without dental prostheses) in 2016. Risk ratios (RRs) and 95% confidence intervals (CIs) were estimated using Poisson regression models with potential confounders as covariates. RESULTS: The analysis included 50,169 participants (mean age: 72.8 [standard deviation, 5.4] years). During follow-up, the incidence of depressive symptoms was 11.3%. Compared to those who had ≥20 teeth, the RR of depressive symptom onset was highest among those who had 0-9 teeth without dental prostheses (RR, 1.27; 95% CI, 1.04-1.56), after the adjustment for confounders. However, this risk was lower in those with 0-9 teeth and dental prostheses (RR, 1.08; 95% CI, 1.01-1.15). CONCLUSIONS: These data highlight the potential of dental prostheses as an important factor in reducing the risk of depressive symptoms among individuals with severe tooth loss.

Oral status and incident functional disability: A 9-year prospective cohort study from the JAGES.

INTRODUCTION: The population-attributable risk of oral status for incident functional disability remains unknown. We investigated the impact of a range of oral statuses (number of remaining teeth, chewing difficulty, dry mouth, and choking) on incident functional disability. METHODS: Participants (n = 44,083) aged ≥ 65 years from the Japan Gerontological Evaluation Study were evaluated. The outcome variable was incident functional disability, and the explanatory variables were four select oral statuses. The possible confounders were included as covariates. Using the Cox proportional hazards model, we calculated hazard ratios (HRs), 95% confidence intervals (CIs), and their population-attributable fractions (PAFs). RESULTS: The mean age of the participants was 73.7 (standard deviation=6.0) years at baseline, and 53.2% were women. A total of 8,091 participants (18.4%) developed functional disabilities during the follow-up period. Among the four oral statuses, the incidence rate of functional disability was the highest in those with chewing difficulty (3.27/100 person-years), followed by those with dry mouth (3.20/100 person-years), choking (3.10/100 person-years), and ≤19 remaining teeth (2.89/100 person-years). After adjusting for all covariates, chewing difficulty showed the highest risk of functional disability (HR=1.22, 95%CI=1.16-1.28), followed by ≤19 remaining teeth (HR=1.18, 95%CI=1.12-1.25), dry mouth (HR=1.18, 95%CI=1.12-1.24), and choking (HR=1.10, 95%CI=1.04-1.17). Regarding PAF, ≤19 remaining teeth (12.0%) were the largest, followed by chewing difficulty (7.2%), dry mouth (4.6%), and choking (1.9%). CONCLUSIONS: Maintaining a good oral status may reduce the risk of functional disability later in life. Given its population contribution, tooth loss had the largest impact among the four oral conditions.

Co-Payments and Inequality in Gingival Bleeding and Dental Visits.

OBJECTIVES: Japan's universal health insurance covers a wide range of dental treatments, and the co-payment rates differ by age. We investigated whether the inequality in gingival bleeding and dental visits was smaller amongst those with lower co-payment rates. METHODS: This cross-sectional study used data from the 2019 Japan Gerontological Evaluation Study. The participants were functionally independent adults aged 65 years or older. The dependent variables were current gingival bleeding as a symptom of periodontal diseases and dental nonattendance for treatment in the past year. The independent variables were ridit scores of equivalent income and educational status. For covariates, we used age, sex, and the number of remaining teeth. To evaluate the inequalities, we used the slope index of inequality (SII) and the relative index of inequality (RII). We also conducted stratified analyses by co-payment rates (30%, 20%, and 10%) to clarify the difference in inequalities by co-payment rate. RESULTS: A total of 15,389 participants were included in the analysis; their mean age was 71.8 (SD = 4.1) and 51.8% were women. There were significant absolute and relative inequalities in gingival bleeding and dental visits by equivalent income and education. With regards to educational status, inequalities were lower with a decrease in the co-payment rate. In particular, relative inequality by education in gingival bleeding was the largest amongst the 30% co-payment group (RII, 1.918; 95% confidence interval [CI], 1.386 to 2.656). For gingival bleeding, the absolute and relative inequality by equivalent income were not significant amongst the 10% co-payment group (SII, -0.003; 95% CI, -0.003 to 0.028; RII, 1.006; 95% CI = 0.676 to 1.498). CONCLUSIONS: A low co-payment rate was associated with smaller inequalities in gingival bleeding and dental visits by equivalent income and educational status.

Large Contribution of Oral Status for Death Among Modifiable Risk Factors in Older Adults: The Japan Gerontological Evaluation Study (JAGES) Prospective Cohort Study.

BACKGROUND: Oral diseases are preventable and modifiable, but highly prevalent, and cause worse oral status. Particularly, tooth loss has increased in aging societies. However, studies on population-attributable risks of modifiable risk factors for mortality have neglected oral status. This study aimed to investigate the impact of modifiable risk factors on mortality, including oral status. METHODS: This cohort study used the Japan Gerontological Evaluation Study data, including participants aged ≥65 years. The outcome was death between August 2010 and March 2017. We calculated the hazard ratios (HRs) and population attributable fraction (PAF) of modifiable risk factors (oral status, hypertension, depression, heart disease, diabetes, physical activity, smoking status, and alcohol drinking history) for mortality. RESULTS: Analyses included 24 175 men and 27 888 women (mean age: 73.8 [6.0] and 74.2 [6.1], respectively). In men, after adjusting for covariates, having no teeth showed the highest hazard ratio (HR = 1.67, 95% confidence interval [CI] = 1.51-1.86) among the modifiable risk factors, and the PAF for the number of teeth (18.2%) was the second largest following age. In women, having no teeth had the third largest HR (HR = 1.37, 95% CI = 1.19-1.56) following current and former smoking. The PAF for the number of teeth (8.5%) was the sixth largest, which was larger than that of smoking status (4.8%). CONCLUSIONS: In the older population, the HR and PAF of the number of teeth on mortality were sufficiently large compared with other modifiable risk factors, especially in men. Therefore, maintaining good oral status should be included more in global health policies.

Difference of income inequalities of denture use by co-payment rates: A JAGES cross-sectional study.

OBJECTIVES: Studies suggest that wearing dentures to restore missing teeth can have a positive impact on health status. However, income inequalities in denture wearing exist. The aim of this study was to investigate how differing co-payment rates under the current Japanese Universal Health Insurance Coverage System affect income inequalities in denture non-use among older adults with severe tooth loss. METHODS: This cross-sectional study used data from the 2019 Japan Gerontological Evaluation Study (JAGES). Self-administered questionnaires were mailed to 345 356 independent people who did not receive long-term care insurance benefits and were aged ≥65 years. The dependent variable was denture non-use, and the independent variable was the equivalent annual household income. The Slope Index of Inequality (SII) and Relative Index of Inequality (RII) were used with regression-based approaches to determine both absolute and relative inequalities in denture non-use by co-payment rates. The covariates were sex, age, years of education, number of teeth and comorbidities. RESULTS: Of the 240 889 responses received (response rate =69.9%), we analysed 21 594 participants who fulfilled the inclusion criteria. The mean age was 72.8 years (standard deviation =4.1), and 57.6% were men. For 30 per cent, 20 per cent and 10 per cent co-payment rates, the percentages of people who did not use dentures and had severe tooth loss (≤9 teeth) were 18.3%, 13.3%, and 8.5%, respectively. All analyses confirmed significant inequalities in denture non-use. The lower the co-payment rate, the smaller the inequalities. SIIs for each co-payment rate were as follows: 30 per cent =13.35% (95% confidence interval [CI] = 9.61-17.09); 20 per cent =7.85% (95% CI = 4.88-10.81); and 10 per cent =4.85% (95% CI = 2.55-7.16). Inclusion of interaction term between income and co-payment rate significantly lowered the inequalities by co-payment rate in logistic regression analysis and SII. For RII, although the interaction was not statistically significant, a similar trend was observed. CONCLUSIONS: Income inequalities in denture use existed among older adults with severe tooth loss in Japan, and the inequalities appeared to be greater when the co-payment rate was higher.

Free Sugar Intake and Periodontal Diseases: A Systematic Review.

High free sugar intake is associated with an increased risk of various non-communicable diseases. We aimed to systematically review articles investigating the association between free sugar intake and periodontal diseases. This systematic review was conducted according to PRISMA guidelines and was registered in the PROSPERO database (CRD42022337828). We obtained articles from PubMed, Web of Science, and Scopus in April 2022. The study selection was performed according to predefined eligibility criteria based on the following PECOS: (P) general population, (E/C) free-sugar-containing food/beverage intake, (O) clinically measured periodontal diseases, and (S) observational study and clinical trial. Of the 839 screened records, 13 studies were included in the review. Most studies (n = 12) had a cross-sectional design. The age groups in the included studies were children/adolescents (n = 5) and adults (n = 8). Among the included studies, 11 reported a significant association between the frequent intake of free-sugar-containing food or beverages and a higher prevalence or incidence of periodontal diseases. The quality of most of the included studies was scored "fair" based on the Newcastle-Ottawa Quality Assessment Scale. Although the majority of the included studies reported a significant positive association between high free sugar intake and periodontal diseases, the evidence is considered to be limited due to the study designs.

Information Usage and Compliance with Preventive Behaviors for COVID-19: A Longitudinal Study with Data from the JACSIS 2020/JASTIS 2021.

The influence of different types of information sources on individual preventive behaviors remains unclear. We aimed to investigate the associations between individual information usage to obtain information about COVID-19 and compliance with preventive behaviors. This longitudinal study was based on an Internet survey conducted in August−September 2020 and February 2021. We used compliance with four preventive behaviors for COVID-19, "wearing a mask", "ventilation", "social distancing", and "avoiding crowds" as outcome variables, and 20 types of information sources based on people or institutions (Medical worker, Government, etc.) and media (TV news, Twitter, etc.) as predictors. Absolute differences and 95% confidence intervals were estimated using generalized estimating equations adjusted for possible confounders. Among the 18,151 participants aged 20−79, the mean age was 51.7 (SD = 15.9) in 2020, and 51.3% were male. In total, compliance with "wearing a mask", "ventilation", "social distancing", and "avoiding crowds" was seen in 86.2%, 46.9%, 45.4%, and 62.6% of individuals in 2020, and 89.3%, 38.2%, 47.2%, and 61.6% of individuals in 2021, respectively. In the multivariate analysis, "medical workers", "professionals", "the government", "Twitter", "news websites", and "TV news" were positively associated with compliance with two or more preventive behaviors (p < 0.05). The type of information source may play an important role in providing information for COVID-19 prevention.

Association of poor dental status with eating alone: A cross-sectional Japan gerontological evaluation study among independent older adults.

Eating alone is reported to deteriorate health; however, the relationship between eating alone and poor dental health remains unclear. This cross-sectional study aimed to investigate the association between poor dental health and eating alone. Data of participants (n = 156,287) aged ≥65 years from the Japan Gerontological Evaluation Study were evaluated using logistic regression to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the association between dental status, including prosthesis use, and eating status. Differences in these associations according to living status were also examined. The mean age of participants was 73.7 (SD = 6.0) years. The percentages of participants eating alone with 20 or more teeth, 10-19 teeth with dental prostheses, 0-9 teeth with dental prostheses, 10-19 teeth without dental prostheses, and 0-9 teeth without dental prostheses were 13.8%, 16.0%, 18.6%, 18.9%, and 27.0%, respectively. After adjusting for covariates, participants with 0-9 teeth without any dental prosthesis showed a significantly higher odds ratio for eating alone (OR = 1.81, 95% CI = 1.58-2.07) than those with 20 or more teeth. Among participants with poorer dental status, the probability of eating alone was higher in those living alone than in those living with others. Among older adults, poor dental status was significantly associated with eating alone, and this association was stronger among those living alone. Maintaining better dental status by using a dental prosthesis might reduce the risk of eating alone, especially for those living alone.

Dental prosthetic treatment reduced the risk of weight loss among older adults with tooth loss.

OBJECTIVES: Weight loss is a critical health issue in older adults. Oral function is essential for nutrient intake and can be restored using dental prosthetic treatments in patients with tooth loss. This study aimed to investigate the relationship between tooth loss and weight loss among the older adults and to evaluate the magnitude of its risk reduction by dental prosthetic treatment. DESIGN: Three-year follow-up longitudinal study based on a self-reported questionnaire. SETTING: Community-dwelling older adults in Japan. PARTICIPANTS: Adults aged 65 and older (n = 53,690). MEASUREMENTS: We used >10% weight loss during follow-up, the number of remaining teeth, and the use of dental prostheses as the outcome variable, exposure variable, and mediator, respectively. We fitted the logistic regression model including possible confounders and calculated the odds ratios (ORs) and 95% confidence intervals (95% CIs) of the controlled direct effect (CDE) at the level of use or nonuse of the dental prosthesis based on a causal mediation analysis framework. Additionally, we calculated the proportion eliminated by the dental prosthesis. RESULTS: The mean age of participants was 72.6 years (1 SD = 5.5), and 47.4% were males. About 5.8% (n = 3132) of them experienced >10% weight loss during the follow-up. Weight loss was observed in 6.8% of the participants with 0-19 remaining teeth and in 4.3% of them with ≥20 remaining teeth. The CDE of 0-19 remaining teeth was greater when no one used dental prosthesis (OR = 1.41; 95% CI = 1.26-1.59) compared with that when all participants used dental prosthesis (OR = 1.26; 95% CI = 1.08-1.46). This indicated that dental prosthesis decreased the risk of weight loss by 37.3%. CONCLUSION: Our study revealed that tooth loss increased the risk of clinically critical levels of weight loss among community-dwelling older adults. However, this risk was reduced by dental prosthetic treatment.

Gene expression profile of Ci-VSP in juveniles and adult blood cells of ascidian.

VSP is a transmembrane protein whose cytoplasmic region shows significant similarity to phosphatase and tensin homolog deleted on chromosome 10 (PTEN). Notably, VSP exhibits a unique ability to transduce electrical signals into phosphoinositide turnover by coupling a transmembrane voltage sensor domain to the PTEN-like phosphoinositide phosphatase domain. Moreover, VSP gene is known to be widely conserved among deuterostome genomes, though the function of VSP in vivo remains largely unknown. In the present study, the expression pattern of ascidian VSP(Ci-VSP) was examined in embryos and juveniles of a marine invertebrate chordate, Ciona intestinalis. RT-PCR showed that Ci-VSP is expressed at the larval stage and that expression persists in juveniles. Whole mount in situ hybridization showed that Ci-VSP is expressed in cells of the stomach, intestine and blood cells of 2- to 3-week-old juveniles. Moreover, double staining blood cells from 2-month-old adults with Ci-VSP and Ci-PTEN probes showed that Ci-VSP-positive cells are a distinct population, separate from cells expressing Ci-PTEN. These findings suggest that in addition to its previously suggested roles in testis or sperm, Ci-VSP plays a key role in voltage-induced signal transduction in cells of the digestive system and blood.

Vitamin K-dependent proteins in Ciona intestinalis, a basal chordate lacking a blood coagulation cascade.

We have isolated and sequenced several cDNAs derived from the sea squirt Ciona intestinalis that encode vitamin K-dependent proteins. Four of these encode gamma-carboxyglutamic acid (Gla) domain-containing proteins, which we have named Ci-Gla1 through Ci-Gla4. Two additional cDNAs encode the apparent orthologs of gamma-glutamyl carboxylase and vitamin K epoxide reductase. Ci-Gla1 undergoes gamma-glutamyl carboxylation when expressed in CHO cells and is homologous to Gla-RTK, a putative receptor tyrosine kinase previously identified in a related ascidian. The remaining three Gla domain proteins are similar to proteins that participate in fundamental developmental processes, complement regulation, and blood coagulation. These proteins are generally expressed at low levels throughout development and exhibit either relatively constant expression (Ci-Gla1, gamma-glutamyl carboxylase, and vitamin K epoxide reductase) or spatiotemporal regulation (Ci-Gla2, -3, and -4). These results demonstrate the evolutionary emergence of the vitamin K-dependent Gla domain before the divergence of vertebrates and urochordates and suggest novel functions for Gla domain proteins distinct from their roles in vertebrate hemostasis. In addition, these findings highlight the usefulness of C. intestinalis as a model organism for investigating vitamin K-dependent physiological phenomena, which may be conserved among the chordate subphyla.

Identification of thirty-four transcripts expressed specifically in hemocytes of Ciona intestinalis and their expression profiles throughout the life cycle.

The innate immunity of ascidian hemocytes is considered to be a prototype of that in vertebrates. In this study, we identified as many transcripts as possible that were expressed specifically in hemocytes of Ciona intestinalis, a ubiquitous species of ascidian. Using a large-scale whole-mount in situ hybridization (WISH) technique and young adult specimens of C. intestinalis, 34 such transcripts were identified. Three of these appeared to encode immunity-related polypeptides, whereas 23 encoded hypothetical and/or new genes. Interestingly, different sets of transcripts appeared to be expressed in different subsets of hemocytes, as revealed by double-colored WISH. The 34 genes were categorized into two major subgroups based on their expression patterns during the C. intestinalis life cycle. Based on the gene expression profiles, we speculate that C. intestinalis hemocytes may exert more pleiotropic effects in immunity than previously believed.