Exploring the association between number of teeth, food intake, and cognitive function: A 9-year longitudinal study.

OBJECTIVES: This study aimed to investigate the association between the number of teeth, food intake, and cognitive function in Japanese community-dwelling older adults. METHODS: This 9-year longitudinal study included a total of 293 analyzable participants who participated in baseline and follow-up surveys. Dental status (number of teeth and periodontal pocket depth), dietary assessment using the brief-type self-administered diet history questionnaire, cognitive function, and the following confounding factors were evaluated: educational level, financial satisfaction, living situation, smoking and drinking habits, history of chronic diseases, apolipoprotein E-ε4 carrier, body mass index, handgrip strength, instrumental activities of daily living, and depressive symptomatology. The Japanese version of the Montreal Cognitive Assessment was used to evaluate cognitive function. A multinomial logistic regression analysis for the intake level of each food categorized into three groups (low, moderate, high), and a generalized estimating equation (GEE) for cognitive function over nine years were performed. RESULTS: After controlling for confounding factors, the number of teeth was shown to be associated with the intake of green-yellow vegetables and meat. Furthermore, the GEE indicated that the lowest quartile of intake of green-yellow vegetables significantly associated with lower cognitive function (unstandardized regression coefficient [B] = -0.96, 95 % confidence interval [CI]: -1.72 to -0.20), and the lowest quartile of intake of meat significantly associated with lower cognitive function (B = -1.42, 95 % CI: -2.27 to -0.58). CONCLUSIONS: The intake of green and yellow vegetables and meat, which is influenced by the number of teeth, was associated with cognitive function in Japanese community-dwelling older adults. CLINICAL SIGNIFICANCE: There are few studies that have examined the association between oral health, food intake, and cognitive function. This 9-year longitudinal study suggests that it is important to maintain natural teeth to enable the functional means to consume green-yellow vegetables and meat, and thereby help maintain cognitive function.

Factors related to subjective evaluation of difficulty in chewing among community-dwelling older adults.

AIM: Awareness of difficulty chewing may limit the diversity of food intake in older adults. However, few studies have clarified which factors are related to subjective difficulty in chewing. The aim was to identify factors related to subjective difficulty in chewing in 70- and 80-year-old Japanese older adults. METHODS: A total of 1680 participants (792 men, 888 women) were surveyed. Difficulty in chewing was assessed with questionnaires regarding food intake, such as rice, apples, beef, and hard rice crackers. The participants were classified into two groups, the "with difficulty" group (participants who answered "cannot eat," "can eat with difficulty," and "can eat if small") and the "without difficulty" group (participants who answered "can eat without problems"), according to their answers to questionnaires for each food. A logistic regression analysis with subjective difficulty in chewing as the dependent variable was performed for each food. RESULTS: Subjective difficulty in chewing was associated with age, occlusal force, and depression for rice; age, number of remaining teeth, occlusal force, and depression for apples; number of remaining teeth, occlusal force, and depression for beef; and number of remaining teeth and occlusal force for hard rice crackers. CONCLUSIONS: Age, number of remaining teeth, and occlusal force, as well as depression, might be related to subjective evaluation of difficulty chewing in community-dwelling Japanese older adults. Geriatr Gerontol Int 2024; 24: 327-333.

The relationship between changes in occlusal support and masticatory performance using 6-year longitudinal data from the SONIC study.

OBJECTIVES: Reduced occlusal support is thought to be related to a decline in masticatory performance. However, previous research in this field was based on cross-sectional studies. In this study, we conducted a 6-year longitudinal observation of older adults living in the community and examined the associations of changes in occlusal support with masticatory performance. METHODS: Of the 864 participants aged 72-74 years in the SONIC study, 488 who were followed up (median follow-up period 5.92 years) and had no missing data were included in this study. Participants were divided into three groups according to the number of occlusal support zones in the posterior area: Complete occlusion (four zones), Reduced occlusion (one to three zones), and Collapsed occlusion (no occlusal support zone). Longitudinal analysis of the relationship between occlusal support and masticatory performance was undertaken with linear mixed-effects models. RESULTS: Sex, occlusal force, number of unreplaced missing teeth, aging, and occlusal support change were significantly related to masticatory performance. Furthermore, the interaction term between change in occlusal support and aging was a significant explanatory variable for the decline in masticatory performance. The interaction was strongest in the group that changed from Complete or Reduced occlusion to Collapsed occlusion. This result indicates that the loss of occlusal support is a major factor contributing to declining masticatory performance. CONCLUSIONS: The decline of occlusal support was greatly associated with the deterioration of masticatory performance. Our results suggest that older adults need to prevent the collapse of posterior occlusal support to maintain their masticatory performance. CLINICAL SIGNIFICANCE: Occlusal support is important for preserving masticatory performance in older adults. Preventing the loss of molars and retaining occlusal support may contribute to maintaining food intake diversity and nutritional status, thereby improving quality of life. Dental professionals need to carefully examine dental status to assess the risk of occlusal collapse.

Relationship between the number of teeth, occlusal force, occlusal contact area, and dietary hardness in older Japanese adults: The SONIC study.

PURPOSE: Individuals with impaired masticatory function tend to prefer soft foods, which results in decreased masticatory muscle activity. This study examined the association between the oral condition (number of teeth, occlusal force, and occlusal contact area) and dietary hardness using a daily dietary questionnaire. METHODS: This cross-sectional study evaluated 1841 participants aged 69-71 and 79-81 years. Registered dentists examined the number of teeth, occlusal force, and occlusal contact area. Dietary hardness was defined as the estimated masticatory muscle activity required for a habitual diet. Habitual diet during the preceding month was assessed using a brief self-administered diet history questionnaire. Confounding factors, such as age, sex, socioeconomic status, smoking habits, history of chronic diseases (hypertension, hyperlipidemia, and diabetes), and cognitive function were also evaluated. Multivariate linear regression analyses were performed to assess the association between dietary hardness and each oral condition. RESULTS: Occlusal force (standardized regression coefficients [ß]=0.08, P < 0.01) and occlusal contact area (ß=0.06, P < 0.01) were significantly associated with dietary hardness after adjusting for the confounding factors. Number of teeth was not significantly associated with dietary hardness. In addition, the associations between dietary hardness, sex, and a history of diabetes were stronger than those between dietary hardness and oral factors. CONCLUSIONS: Occlusal force and contact area were significantly associated with dietary hardness as estimated from the masticatory muscle activity using a daily diet questionnaire.

Predictive factors for tooth loss in older adults vary according to occlusal support: A 6-year longitudinal survey from the SONIC study.

OBJECTIVES: The aim of this cohort study among community-dwelling older adults aged over 70 years was to investigate the influence of occlusal support on tooth loss, and to determine predictive factors for tooth loss for each occlusal support category using multilevel analyses. METHODS: Participants were 812 older adults who completed the baseline survey and the follow-up survey 6 years later. The Eichner index was used to evaluate occlusal support status. A generalized estimating equation (GEE) logistic regression analysis was used to examine the influence of occlusal support status on tooth loss while adjusting for various factors at individual and tooth levels. Similar analyses were separately performed in each Eichner class to determine predictive factors for tooth loss. RESULTS: The GEE showed that a decline in occlusal support increased the risk of tooth loss (Eichner A: reference category, Eichner B: odds ratio (OR) = 1.96, p < 0.001, Eichner C: OR = 3.04, p < 0.001). Stratified analysis showed that deeper periodontal pockets and abutment teeth for fixed partial dentures were significantly associated with tooth loss, regardless of occlusal support. In Eichner A, the presence of an opposing tooth was advantageous in protecting the tooth, and a missing adjacent tooth was not significantly associated with tooth loss. An opposing tooth was associated with the risk of tooth loss in Eichner B, and a missing adjacent tooth was significantly associated with tooth loss in Eichner B and C. CONCLUSIONS: A decline in occlusal support accelerated tooth loss. Predictive factors for tooth loss varied depending on occlusal support status. CLINICAL SIGNIFICANCE: Occlusal support is an important factor in preventing tooth loss. Dentition conditions such as missing adjacent teeth and the presence of opposing teeth increase the risk of tooth loss in participants with poor occlusal support. Dental personnel need to carefully examine dentition conditions to assess the risk of occlusal collapse.

Decline of oral functions in old-old adults and their relationship with age and sex: The SONIC study.

BACKGROUND: Many physical functions decline with aging, but it is not known whether oral functions vary according to sex or decline with aging, as it occurs with physical functions. The present study aimed to examine the association of sex, age, and elapsed years with occlusal force and tongue pressure using a generalized linear mixed-effect model (GLMM) over a 3-year period among old-old Japanese adults. METHODS: Participants were community-dwelling older adults who participated in a survey (June 2014-March 2017) and a follow-up survey (July 2017-December 2019) after 3 years (n = 951: 70-year group, n = 466; 80-year group, n = 391; 90-year group, n = 94). Dental examinations including the number of teeth, occlusal force, and tongue pressure were conducted, and a GLMM was used to estimate the association of sex, age, and elapsed years with occlusal force and tongue pressure, adjusting for the number of teeth. RESULTS: The GLMM showed that occlusal force was significantly associated with sex (reference; male, non-standardized coefficient: B = -66.9 [female], p < 0.001), age (reference; 70-year group, B = -81.7 [80-year group], p < 0.001, B = -87.2 [90-year group], p < 0.001), and the number of teeth (B = 13.8, p < 0.001), but did not significantly decrease with elapsed years. Tongue pressure was significantly associated with sex (reference; male, B = -0.94 [female], p = 0.034) and age (reference; 70-year group, B = -1.78 [80-year group], p < 0.001, B = -5.47 [90-year group], p < 0.001). Tongue pressure decreased significantly with elapsed years (B = -0.82, p < 0.001). CONCLUSIONS: These findings suggest that tongue pressure significantly decreased over time, but occlusal force did not. Tongue-related muscles may be more susceptible to aging than masticatory muscles.

Oral Functions Are Associated with Muscle Strength and Physical Performance in Old-Old Japanese.

Grip strength and walking speed are considered to be important indicators of physical frailty. However, no study has contemporaneously examined any association of multiple oral functions with grip strength and walking speed. The purpose of this study was to examine which oral functions are associated with muscle strength (grip strength), physical performance (walking speed) or both. The study participants were 511 community-dwelling people (254 men and 257 women) aged 77-81 years old. Six oral functions-oral wetness, occlusal force, tongue-lip motor function, tongue pressure, masticatory performance and swallowing function-were measured. Grip strength and walking speed were also measured. A partial correlation analysis, adjusted for gender, showed that occlusal force, tongue-lip motor function, masticatory performance and swallowing function were significantly associated with both grip strength and walking speed. In addition, tongue pressure was significantly associated with grip strength. A general linear model showed that tongue pressure and occlusal force were significantly associated with grip strength. Swallowing function and tongue-lip motor function were significantly associated with walking speed. It is suggested that there are different oral function measures for muscle strength and physical performance, and these oral function measures could be a useful proxy for physical frailty.

Impact of occlusal force on decline in body mass index among older Japanese adults: Finding from the SONIC study.

OBJECTIVES: To determine any independent influence of occlusal force and of number of natural teeth on decline in body mass index (BMI) among older Japanese adults. DESIGN: Longitudinal study over a 3- to 6-year period. SETTING: Urban and rural area in Japan. PARTICIPANTS: Independently living Japanese adults aged 69-71 years and 79-81 years at baseline. This analysis excluded participants who were defined as underweight at baseline. MEASUREMENTS: Information was collected on age, gender, occlusal force, the number of teeth, BMI, socioeconomic factors, medical history, the number of daily prescription medications, cognitive function, depressive symptoms, hand grip strength, and physical function. Maximal occlusal force was measured with a pressure-sensitive sheet. Nutritional status was assessed using BMI, and participants with BMI <21.5 were defined as underweight. Then, they were divided into two groups: a "BMI declined" group who were defined as underweight at either 3- or 6-year follow-up survey, and a "BMI maintained" group who were not defined as underweight at both follow-up surveys. Logistic generalized estimating equation (GEE) models were used to assess the effect of occlusal force and the number of teeth at baseline on decline in BMI over 3 or 6 years, after adjusting for possible covariates associated with nutritional status. RESULTS: The final analysis included 704 participants. Eighty-six (12.2%) participants were classified into the BMI declined group. Logistic GEE models showed that the number of teeth was not significantly associated with decline in BMI. However, occlusal force was significantly associated with decline in BMI (odds ratio = 0.90, 95% confidence interval = 0.83-0.97) after adjusting for covariates. CONCLUSION: Participants with lower occlusal force were more likely to be in the BMI less than 21.5 kg/m2 . The findings suggest that to prevent decline in oral function is important to maintain nutritional status.

Association of periodontal disease with atherosclerosis in 70-year-old Japanese older adults.

Periodontal disease and arteriosclerotic disease are greatly affected by aging. In this study, the association of conventional risk factors and periodontal disease with atherosclerosis was longitudinally examined in Japanese older adults. Subjects in this study were 490 community-dwelling septuagenarians (69-71 years) randomly recruited from the Basic Resident Registry of urban or rural areas in Japan. At the baseline examination, all subjects underwent socioeconomic and medical interviews; medical examinations, including examinations for carotid atherosclerosis, hypertension, diabetes mellitus, and dyslipidemia; and conventional dental examinations, including a tooth count and measurement of probing pocket depth (PPD). After 3 years, 182 septuagenarians who had no atherosclerosis at the baseline examination were registered and received the same examination as at the baseline. In the re-examination conducted 3 years after the baseline survey, 131 (72.0%) of the 182 participants who had no atherosclerosis at the baseline examination were diagnosed with carotid atherosclerosis. Adjusting and analyzing the mutual relationships of the conventional risk factors for atherosclerosis by multiple logistic regression analysis for the 171 septuagenarians with a full set of data, the proportion of teeth with PPD ≥ 4 mm was independently related to the prevalence of atherosclerosis (odds ratio: 1.029, P < 0.022). This longitudinal study of Japanese older adults suggests that periodontal disease is associated with the onset/progression of atherosclerosis. Maintaining a healthy periodontal condition may be an important factor in preventing the development and progression of atherosclerosis.

Determination of the lingual border of lower complete dentures: How to use a silicone impression material?

OBJECTIVES: This study aimed to clarify the efficacy of a border-moulding procedure with low-flow silicone impression material compared with a conventional compound to complete denture fabrication. It also aimed to evaluate the influence of various functional tasks during the lingual-side moulding procedure regarding the depth and width of the border. METHODS: Ten dentate subjects (three men, seven women; average age 30 years) were enrolled in this study after giving informed consent. A specially designed custom impression tray for the mandibular lingual side was fabricated for each subject. With the tray and heavy-body-type silicone material, lingual border moulding was performed that included four functional tasks: tongue protrusion (TP), licking the upper lip with the tongue (UL), swallowing (SW), and placing the tongue tip to the palate (PP). RESULTS: Within the limitations of this study, the results suggested that heavy-body silicone impression material is satisfactory for use in the border-moulding procedure, giving reproducible results. CONCLUSION: There were no significant differences among the functional tasks regarding the depth and width of the lingual flange except for swallowing, which exhibited the largest values.

Occlusal force predicted cognitive decline among 70- and 80-year-old Japanese: A 3-year prospective cohort study.

PURPOSE: Dementia is a growing health problem for countries with aging populations, but few effective dementia treatments are available. However, there is increasing interest in oral health as a modifiable risk factor in interventions to prevent cognitive decline. This study aimed to investigate the impact of oral health on the decline of cognitive function over 3 years among Japanese people aged 70 and 80 years. METHODS: Participants (n = 860) were community-dwelling older adults who participated in baseline and follow-up surveys (at baseline: 69-71 years n = 423; 79-81 years, n = 437). Registered dentists examined the number of teeth, number of functional teeth, number of periodontal teeth, and occlusal force. The Japanese version of the Montreal Cognitive Assessment was used to evaluate cognitive function. We also evaluated socioeconomic factors, medical history, drinking and smoking habits, physical performance, genetic factors, and C-reactive protein concentration in blood. A generalized estimating equation (GEE) was used to examine how oral health at baseline influenced cognitive decline over 3 years. RESULTS: The GEE showed that the number of teeth (non-standardized coefficient: B = 0.031, p = 0.022) and occlusal force (B = 0.103, p = 0.004) at baseline were associated with cognitive function at follow-up, even after adjusting for other risk factors. Furthermore, maintaining more teeth (B = 0.009, p = 0.004) and a stronger occlusal force (B = 0.020, p = 0.040) buffered cognitive decline. CONCLUSIONS: Number of teeth and occlusal force predict cognitive decline over 3 subsequent years in Japanese older adults aged 70 and 80 years.

Occlusal support predicts tooth loss in older Japanese people.

OBJECTIVES: Many older people lose their teeth. However, few studies have examined whether the number of remaining teeth or the amount of occlusal support is more important for tooth loss that occurs in older age after adjusting for systemic factors. The purpose of this study was to investigate comprehensively the factors related to tooth loss over a period of 6 years, including occlusal support in 70- and 80-year-old community-dwelling Japanese people. METHODS: This cohort study included 296 participants in the 70-year-old group and 232 in the 80-year-old group. The number of teeth of all participants was recorded at baseline and after 6 years, and the participants were divided into two groups according to the number of teeth lost (0 or 4 or more). Occlusal support was classified into three groups based on posterior occlusal support. Mean probing pocket depth, tooth brushing habits, frequency of dental check-ups, education level, economic status and systemic factors (carotid atherosclerosis, hypertension, diabetes mellitus, dyslipidemia, cognitive function and smoking habits) were evaluated. Multiple logistic regression analysis was performed to investigate the relationship of tooth loss with occlusal support and systemic factors. RESULTS: Logistic regression analysis revealed that mean probing pocket depth (odds ratio [OR] = 5.70, 95% confidence interval [CI] = 2.70-12.04, P < .01) and posterior occlusal support (reference = Eichner class A; Eichner B1-3, OR = 4.33, 95% CI = 1.54-12.17, P < .01; Eichner B4 or C, OR = 6.16, 95% CI = 1.17-32.44, P = .03) were associated significantly with the loss of four or more teeth. CONCLUSIONS: This study revealed that age itself is not a predictor of multiple tooth loss in community-dwelling older Japanese people. Deep mean probing pocket depth and a lack of posterior occlusal support were significantly associated with the loss of four or more teeth.

Lack of posterior occlusal support predicts the reduction in walking speed in 80-year-old Japanese adults: A 3-year prospective cohort study with propensity score analysis by the SONIC Study Group.

OBJECTIVE: To investigate the association between posterior occlusal support by residual teeth and the reduction in walking speed in 80-year-old Japanese adults using propensity score matching. BACKGROUND DATA DISCUSSING THE PRESENT STATUS OF THE FIELD: Previous studies have demonstrated an association between oral status and motor function; however, most of these studies had a cross-sectional design. MATERIAL AND METHOD: This study included 353 community-dwelling Japanese people aged 79-81 years. Low walking speed was defined as ≤0.8 m/s, and participants with a low walking speed at baseline were excluded. The participants were divided into two groups: with or without posterior occlusal support by residual teeth at baseline. Propensity score matching was used to reduce the effects of bias by matching participants with and without posterior occlusal support according to similar background factors at baseline. Conditional logistic regression was conducted to determine low walking speed at the 3-year follow-up, which included posterior occlusal support as an independent variable with matching data. RESULTS: Before matching for posterior occlusal support, significant differences existed between the groups in terms of sex, years of education, height, weight and grip strength. However, after matching, there was no significant difference between the groups in any characteristic. Logistic regression analysis showed that posterior occlusal support is a significant variable (odds ratio = 1.88; P = 0.04) associated with reduced walking speed. CONCLUSION: Lack of posterior occlusal support at baseline independently predicted the incidence of reduced walking speed over 3 years.

Impact of cognitive function on oral perception in independently living older people.

OBJECTIVES: Oral tactile perception is important for better mastication, appetite, and enjoyment of food. However, previous investigations have not utilized comprehensible variables thought to have negative effect on oral perception, including aging, denture wearing, and cognitive function. The aim of this study was to elucidate the impact of cognitive function on oral perception in independently living older individuals. MATERIALS AND METHODS: The study sample was comprised of 987 participants (466 males, 521 females; age 69-71 years). Oral examinations, assessments of cognitive function in preclinical level by Montreal Cognitive Assessment (MoCA)-J, and determination of oral stereognostic ability as an indicator of oral perception were performed. Related variables were selected by univariate analyses; then, multivariate logistic regression model analysis was conducted. RESULTS: Univariate analyses revealed that number of teeth, removable dentures usage, and cognitive function respectively had a significant relationship with stereognostic score. Next, the subjects were classified into good and poor perception groups (lowest 17.4%) according to oral stereognostic ability. Logistic regression analysis revealed that lower cognitive function was significantly associated with poor oral perception (OR = 0.934, p = 0.017) after controlling for other variables. CONCLUSIONS: Cognitive decline even in preclinical stage was associated with reduced oral perception after controlling for gender, tooth number and denture use in independent living older people. CLINICAL RELEVANCE: This study suggested that preclinical level of change in cognitive function affected oral perception. Dental practitioners and caregivers may need to pay attention to reduced oral perception among older people even if they do not have trouble in daily life.

Relationship between oral stereognostic ability and dietary intake in older Japanese adults with complete dentures.

PURPOSE: Oral stereognostic ability (OSA) is a useful indicator of oral perception to recognize food characteristics during mastication. Previous studies have shown associations between dietary intake and oral health status, such as taste perception. However, the effect of oral sensory ability on dietary intake is unclear. The purpose of this study was to investigate the association between oral sensory ability and dietary intake in older Japanese complete denture wearers. METHODS: This cross-sectional study included 164 participants aged 69-71 or 79-81years old, wearing both maxillary and mandibular complete dentures. OSA test was used to evaluate oral tactile perception. Diet during the preceding month was assessed using a self-administered diet history questionnaire. Multivariable linear regression analysis was conducted to assess the association between OSA score and food and nutrient intake after adjusting for age, sex, socioeconomic factors, and occlusal force. RESULTS: The bivariate analysis showed that OSA score was significantly and positively correlated with intake of green and yellow vegetables and negatively correlated with intake of cereals among examined foods. OSA score was also positively correlated with intake of vitamins A, B2, and C and α-tocopherol (as a substitute for vitamin E) among examined nutrients. After adjusting for age, sex, socioeconomic factors, and occlusal force, OSA score remained significantly associated with intake of green and yellow vegetables and α-tocopherol. CONCLUSIONS: OSA was significantly associated with intake of green and yellow vegetables in older complete denture wearers.

Influence of lack of posterior occlusal support on cognitive decline among 80-year-old Japanese people in a 3-year prospective study.

AIM: Previous studies have reported significant associations between tooth loss or periodontal status and cognitive function; however, animal experimental studies have shown that occlusion might be a more important factor in cognitive decline. The purpose of the present study was to investigate the influence of a lack of posterior occlusal support by residual teeth on the decline of cognitive function over a 3-year period among 80-year-old Japanese people. METHODS: Participants were community-dwelling older adults (n = 515, age 79-81 years). Cognitive function was measured using the Japanese version of the Montreal Cognitive Assessment. At baseline, participants were divided into two groups: those with and without posterior occlusal support. Participants whose Japanese version of the Montreal Cognitive Assessment score decreased by ≥3 points over the 3-year period were defined as the declined group. Logistic regression was carried out for the decline in Japanese version of the Montreal Cognitive Assessment scores, including dental status and possible risk factors as independent variables. RESULTS: More participants without posterior occlusal support tended to be in the cognitive decline group (49.4%) than in the maintained group (38.5%; χ2 -test, P = 0.02). Logistic regression analysis showed that a lack of posterior occlusal support was a significant variable (odds ratio 1.55, P = 0.03) for cognitive decline, even after adjusting for other risk factors. However, the number of teeth or mean periodontal pocket depth was not significantly correlated with cognitive decline. CONCLUSIONS: The present findings suggest that a lack of posterior occlusal support predicted the incidence of cognitive decline, even after adjusting for possible risk factors in community-dwelling old-old people. Geriatr Gerontol Int 2018; 18: 1439-1446.

Relationship between gerotranscendence and oral health-related quality of life.

OBJECTIVES: The purpose of our cross-sectional study was to investigate the relationship between gerotranscendence and oral health-related quality of life (OHR-QOL). To our knowledge, this is the first study to investigate the relationship between gerotranscendence and OHR-QOL. METHODS: Participants (total n = 1969; 70-year-old group, n = 999; 80-year-old group, n = 970) were drawn from resident lists in four areas of Japan: one urban area and one rural area in each of two geographical regions. OHR-QOL was measured using the Geriatric Oral Health Assessment Index (GOHAI). Measurement of occlusal force was performed using pressure-sensitive sheets. Gerotranscendence was assessed with the Japanese Gerotranscendence Scale Revised (JGS-R). We used multiple linear regression analysis to examine the relationships among OHR-QOL and other variables. RESULTS: Geriatric Oral Health Assessment Index score was significantly correlated with occlusal force, number of teeth, financial status and JGS-R score on linear regression analysis. CONCLUSION: Degree of gerotranscendence was significantly and independently correlated with degree of OHR-QOL in our sample.

Association of handgrip strength with various oral functions in 82- to 84-year-old community-dwelling Japanese.

OBJECTIVE: The purpose of this study was to elucidate the associations between muscle strength and several oral functions in a large cohort of community-dwelling, 82- to 84-year-old community-dwelling Japanese people. BACKGROUND DATA DISCUSSING THE PRESENT STATUS OF THE FIELD: Several studies have examined the relationships between physical performance and oral functions. However, no studies have investigated the associations of muscle strength with various objectively evaluated oral functional parameters in a large cohort of very old adults. MATERIALS AND METHODS: This study included 809 community-dwelling Japanese people (407 men and 402 women) aged 82-84 years. The oral functions examined were the maximal occlusal force, masticatory performance, stimulated salivary flow rate, repetitive saliva-swallowing test (RSST) score, tongue pressure and mouth-opening distance. Handgrip strength was measured, and its correlations with oral functions were assessed. Multiple linear and logistic regression analyses were performed to investigate the relationships between oral functions and handgrip strength. RESULTS: Multivariate analysis revealed that handgrip strength was correlated with not only the maximal occlusal force, masticatory performance and tongue pressure but also the RSST score and mouth-opening distance after adjustment for sex, number of teeth, use of removable denture, periodontal condition, instrumental activities of daily living, body mass index. When we examine the elderly people whose handgrip strength is declining, we should predict that their various oral functions may be declining. CONCLUSION: Handgrip strength was related to various oral functions after adjustment for the number of teeth in this population of community-dwelling 82- to 84-year-old Japanese.

Occlusal force is correlated with cognitive function directly as well as indirectly via food intake in community-dwelling older Japanese: From the SONIC study.

BACKGROUND: Growing evidence suggests that oral health may be an important factor associated with cognitive function in aged populations. However, many previous studies on this topic used insensitive oral indicators or did not include certain essential covariates. Thus, we examined the association between occlusal force and cognitive function in a large sample of older adults, controlling for dietary intake, vascular risk factors, inflammatory biomarkers, depression, and genetic factors. METHODS: In this cross-sectional study of older community-dwelling Japanese adults, we examined data collected from 994 persons aged 70 years and 968 persons aged 80 years. Cognitive function was measured using the Japanese version of the Montreal Cognitive Assessment (MoCA-J). Oral status and function were evaluated according to the number of remaining teeth, periodontal pocket depth, and maximal occlusal force. Associations between MoCA-J scores and occlusal force were investigated via bivariate and multivariate analyses. RESULTS: Education level, financial status, depression score, and intake of green and yellow vegetables, as well as number of teeth and occlusal force, were significantly correlated with MoCA-J scores in both age groups. Among individuals aged 80 years, CRP and periodontal status were weakly but significantly associated with MoCA-J score. After controlling for all significant variables via bivariate analyses, the correlation between maximal occlusal force and cognitive function persisted. A path analysis confirmed the hypothesis that cognitive function is associated with occlusal force directly as well as indirectly via food intake. CONCLUSIONS: After controlling for possible factors, maximal occlusal force was positively associated with cognitive function directly as well as indirectly through dietary intake.