Associations of Dental Health With the Progression of Hippocampal Atrophy in Community-Dwelling Individuals: The Ohasama Study.

BACKGROUND AND OBJECTIVES: Although tooth loss and periodontitis have been considered risk factors of Alzheimer disease, recent longitudinal researches have not found a significant association with hippocampal atrophy. Therefore, this study aimed to clarify a longitudinal association between the number of teeth present (NTP) and hippocampal atrophy dependent on the severity of periodontitis in a late middle-aged and older adult population. METHODS: This study included community-dwelling individuals aged 55 years or older who had no cognitive decline and had undergone brain MRI and oral and systemic data collection twice at 4-year intervals. Hippocampal volumes were obtained from MRIs by automated region-of-interest analysis. The mean periodontal probing depth (PD) was used as a measure of periodontitis. Multiple regression analysis was performed with the annual symmetric percentage change (SPC) of the hippocampal volume as the dependent variable and including an interaction term between NTP and mean PD as the independent variable. The interaction details were examined using the Johnson-Neyman technique and simple slope analysis. The 3-way interaction of NTP, mean PD, and time on hippocampal volume was analyzed using a linear mixed-effects model, and the interaction of NTP and time was examined in subgroups divided by the median mean PD. In all models, dropout bias was adjusted by inverse probability weighting. RESULTS: Data of 172 participants were analyzed. The qualitative interaction between NTP and the mean PD was significant for the annual SPC in the left hippocampus. The regression coefficient of the NTP on the annual SPC in the left hippocampus was positive (B = 0.038, p = 0.026) at the low-level mean PD (mean -1 SD) and negative (B = -0.054, p = 0.001) at the high-level mean PD (mean +1 SD). Similar results were obtained in the linear mixed-effects model; the interaction of NTP and time was significant in the higher mean PD group. DISCUSSION: In a late middle-aged and older cohort, fewer teeth were associated with a faster rate of left hippocampal atrophy in patients with mild periodontitis, whereas having more teeth was associated with a faster rate of atrophy in those with severe periodontitis. The importance of keeping teeth healthy is suggested.

Regular dental visits, periodontitis, tooth loss, and atherosclerosis: The Ohasama study.

OBJECTIVE: We aimed to explore the association between regular dental visits and atherosclerosis and between periodontitis, number of remaining teeth, and atherosclerosis among community dwellers in Japan. BACKGROUND: Few studies have examined the association between regular dental visits, periodontitis, tooth loss, and atherosclerosis in community dwellers in Japan. METHODS: The participants of this cross-sectional study included community dwellers aged ≥55 years and residing in Ohasama. Exposure variables were regular dental visits; periodontitis, defined as radiographic alveolar bone loss (BL); the Centers for Disease Control/American Academy of Periodontology (CDC/AAP) classification; and number of remaining teeth. The primary outcome was atherosclerosis, defined as maximum carotid intima-media thickness ≥1.1 mm or confirmation of atheromatous plaque. RESULTS: Of 602 participants, 117 had atherosclerosis. In the multivariate model, compared to those with regular dental visits, the odds ratio (OR) (95% confidence intervals [CIs]) of atherosclerosis among those with the absence of regular dental visits was 2.16 (1.03-4.49). Regarding BL-max, compared with those in the first quartile, ORs (95% CIs) of those in the second, third, and fourth quartiles were 1.15 (0.65-2.30), 0.65 (0.32-1.35), and 1.57 (0.81-3.01), respectively. Regarding CDC/AAP classification, compared to those with no or mild periodontitis, ORs (95% CIs) for those with moderate and severe periodontitis were 2.48 (0.61-10.1) and 4.26 (1.01-17.5), respectively. Regarding the number of remaining teeth, compared to those with ≥20 teeth, ORs (95%CIs) for those with 10-19 and 1-9 teeth were 1.77 (1.004-3.12) and 0.96 (0.52-1.80), respectively. CONCLUSION: The absence of regular dental visits and presence of periodontitis are associated with atherosclerosis among community dwellers in Japan.

Relationship between maximum occlusal force and gastrointestinal cancer in community-dwelling older Japanese adults.

Globally, the cancer burden is expected to increase as populations are ageing. Therefore, cancer prevention among older age groups is important. This prospective cohort study examined the relationship between the number of remaining teeth, maximum occlusal force, and incidence of gastrointestinal cancer in community-dwelling older Japanese individuals using data from the Tsurugaya project; 847 participants were included. The exposure variables were the number of remaining teeth and the maximum occlusal force, with the outcome being the incidence of gastrointestinal cancer. Covariates were age, sex, medical history, smoking, alcohol consumption, educational attainment, and physical function. The Cox proportional hazard model was used to examine the relationship between the number of remaining teeth, maximum occlusal force, and incidence of gastrointestinal cancer. With a median follow-up of 7.6 years, 63 participants were confirmed to have gastrointestinal cancer. The risk of gastrointestinal cancer was significantly higher in those with an occlusal force lower than the median (hazard ratio, 2.80; 95% confidence interval, 1.54-5.10). No significant risk difference was found according to the number of remaining teeth. Low maximum occlusal force was associated with the incidence of gastrointestinal cancer in community-dwelling older Japanese adults.

Oral health-related quality of life is associated with the prevalence and development of depressive symptoms in older Japanese individuals: The Ohasama Study.

OBJECTIVE: This prospective study investigated the cross-sectional association between impaired oral health-related quality of life (OHRQoL) and the prevalence of depressive symptoms, and the longitudinal association between impaired OHRQoL and development of depressive symptoms among older adults. BACKGROUND: Previous studies have shown a relationship between poor oral health and depression among older adults; however, findings are inconsistent. MATERIALS AND METHODS: Participants were 669 community-dwelling older Japanese individuals aged≥55 years (mean: 67.8 ± 7.2 years). Data of 296 participants were used for longitudinal analyses. OHRQoL was evaluated using the Oral Impacts on Daily Performances scale. Impaired OHRQoL was defined as the presence of at least one impact on the scale. Depressive symptoms were assessed using the Japanese version of the Zung self-rating depression scale with a cut-off score of 40. RESULTS: The cross-sectional logistic regression model demonstrated that impaired OHRQoL was significantly associated with depressive symptoms (odds ratio [OR], 5.17; 95% confidence interval [CI], 2.99-8.95) independent of age, sex, body mass index, hypertension, cerebrovascular/cardiovascular disease, smoking, drinking alcohol, education, cognitive function, objective oral health (dentition status) and oral health behaviour (dental visit within 1 year). Similarly, impaired OHRQoL predicted the development of depressive symptoms within 4 years in a fully adjusted longitudinal model (OR, 6.00; 95% CI, 1.38-26.09). CONCLUSION: Impaired OHRQoL was identified as a potential comorbidity of depressive symptoms and a predictor for depressive disorder later in life. OHRQoL may be a useful clinical outcome for elder patients with regard to their mental and oral health.

Relationship Between Oral Health and Fractures in Community-Dwelling Older Japanese Adults.

OBJECTIVE: To investigate the relationship between poor oral health and the incidence of fall-related fractures in older Japanese individuals. DESIGN: A 9-year prospective cohort study. SETTING AND PARTICIPANTS: Participants comprised 937 community-dwelling older Japanese adults aged 70 years or older. They all lived in the Tsurugaya district, a suburban area of Sendai city, and underwent comprehensive geriatric assessment, including an oral examination, in a public facility. MEASUREMENTS: The exposure variables were related to oral health status (posterior occlusal support, number of remaining teeth, and occlusal force). The outcome measure was the incidence of fall-related fractures, which was determined by National Health Insurance data. Analyzed covariates included age, sex, medical history, smoking, alcohol drinking, educational level, depressive symptoms, cognitive impairment, physical function, body mass index, and history of falls. Statistical relationships were examined by calculating hazard ratios (HRs) at 95% confidence intervals (CIs) using the Cox proportional hazard model. RESULTS: In the multivariate analysis, the HRs of fall-related fractures were significantly higher in those with unilateral posterior occlusal support (HR, 2.72; 95% CI, 1.13-6.55) and no posterior occlusal support (HR, 2.58; 95% CI, 1.29-5.15) than in those with bilateral posterior occlusal support. The HRs (95% CIs) of fall-related fractures in individuals with 10-19 and 1-9 teeth and edentulous individuals were 1.77 (0.81-3.89), 2.67 (1.24-5.75), and 2.31 (1.01-5.28), respectively, compared to those with ≥20 teeth. CONCLUSIONS AND IMPLICATIONS: Poor oral health status is a risk factor for the incidence of fall-related fractures in community-dwelling older Japanese individuals. The findings suggest that attention should be focused on oral health status to further understand the risk of fall-related fractures among community-dwelling older adults.

Cognitive impairment and depressive symptoms lead to biases in self-evaluated masticatory performance among community-dwelling older Japanese adults: the Tsurugaya Project.

OBJECTIVE: This cross-sectional study aims to examine if cognitive impairment, depressive symptoms, and their combination are associated with biases between self-evaluated and measured masticatory performance in community-dwelling older Japanese adults. METHODS: The sample constituted of 804 community-dwelling elderly Japanese individuals aged ≥70 years. Cognitive impairment and depressive symptoms were assessed using the Mini-Mental State Examination and Geriatric Depression Scale, respectively. Self-evaluated masticatory performance (SMP) was assessed for 10 food items. Measured masticatory performance (MMP) was assessed as the maximum occlusal force, which is a surrogate indicator. Multivariate logistic regression was applied to examine the associations of cognitive impairment, depressive symptoms, and their combination with the deviation between SMP and MMP, SMP overestimation, and SMP underestimation, with adjustment for age, sex, body mass index, smoking, alcohol consumption, duration of education, medical history, physical function, regular dental visits, and number of teeth. RESULTS: Cognitive impairment was significantly associated with SMP overestimation (odds ratio [OR]: 2.37, 95% confidence interval [CI]: 1.25-4.50); in parallel, SMP underestimation was significantly associated with depressive symptoms (OR: 1.86, 95% CI: 1.14-3.04) and the presence of both cognitive impairment and depressive symptoms (OR: 2.77, 95% CI: 1.01-7.61). CONCLUSIONS: This cross-sectional study clarifies the gap between self-evaluated and measured masticatory performance in geriatric participants who have cognitive impairment or depressive symptoms. These biases must be taken into consideration when appraising self-evaluated masticatory performance or oral health status in geriatric patients with cognitive impairment or depressive symptoms. CLINICAL SIGNIFICANCE: This study explores the biases in geriatric patients with cognitive impairment or symptoms of depression. It clarifies that participants with cognitive impairment tend to overestimate their self-evaluated masticatory performance. Conversely, the participants with depression symptoms tend to underestimate their self-evaluated masticatory performance.

Contribution of systemic inflammation and nutritional status to the relationship between tooth loss and mortality in a community-dwelling older Japanese population: a mediation analysis of data from the Tsurugaya project.

OBJECTIVES: To assess whether systemic inflammation and nutritional status contribute to a relationship between tooth loss and mortality in community-dwelling older Japanese individuals using mediation analyses. MATERIALS AND METHODS: This longitudinal study targeted community-dwelling older Japanese individuals (N = 891). The exposure variable was the number of teeth (edentulous, 1-9, 10-19, ≥ 20), while the outcome was all-cause mortality from 2003 to 2016. Nutritional status and systemic inflammation were evaluated as mediators and based on serum albumin and high-sensitivity C-reactive protein levels, respectively. Covariates included age, sex, smoking, alcohol consumption, medical history, educational level, depressive symptoms, cognitive impairment, and physical function. The Cox proportional hazards model was applied to calculate hazard ratios (HRs) for the association between tooth loss and mortality and the contributions of systemic inflammation and nutritional status to this association. RESULTS: Edentulous participants (HR, 1.84; 95 % confidence interval [CI], 1.30-2.59) and those with 1-9 teeth (HR, 1.75; 95% CI, 1.28-2.40) groups exhibited a significantly higher risk of mortality than did those with ≥ 20 teeth. Mediation analyses showed that nutritional status contributed to the association between tooth loss and mortality in participants with 1-9 teeth, whereas systemic inflammation played no role in this association. CONCLUSIONS: Nutritional status may contribute to the association between tooth loss and mortality in community-dwelling older Japanese individuals with fewer remaining teeth. CLINICAL RELEVANCE: The data from this prospective cohort study help in elucidating parts of the biological mechanism underlying tooth loss and all-cause mortality in older individuals.