Associations Between Occupational Status, Support at Work, and Salivary Cortisol Levels.

OBJECTIVE: The present study investigated associations between occupation, job stress, and salivary cortisol levels after psychological tasks. METHODS: We examined 766 (273 men and 493 women) healthy employed Japanese participants aged 21 to 68 years (mean age = 46.4 years, standard deviation = 8.5) with three types of occupation: manager, teacher, and general worker. The Brief Job Stress Questionnaire was used to evaluate participants' job stress levels, including job demand, job control, support from supervisors, and support from coworkers. Salivary cortisol levels were measured at pre-session, post-stressful tasks, and post-relaxation. All samples were assayed using an enzyme-linked immunosorbent assay test. Natural log transformation was applied before statistical analyses. A multiple regression analysis and a repeated measures analysis of covariance were conducted to test associations between occupation and salivary cortisol levels, adjusting for confounding factors. Statistical analyses were conducted separately for men and women. RESULTS: Among both men and women, general workers had higher cortisol levels than managers throughout the experimental session (men 0.6 µg/dL and 0.4 µg/dL, respectively; women 0.5 µg/dL and 0.4 µg/dL, respectively). Job control was positively associated with cortisol levels measured in all sessions, after adjusting for confounding factors (standardized beta 0.15, 0.21, and 0.18 for pre-session, post-stressful-tasks, and post-relaxation, respectively, all p < 0.05). Men with low support from coworkers had higher cortisol levels than those with high support through the sessions (0.6 µg/dL and 0.4 µg/dL, respectively). CONCLUSION: Socioeconomic disparity according to occupational status was related to cortisol levels in Japanese workers. Support from coworkers may be effective for reducing cortisol secretion in men.

Interrelationships among whole-body skeletal muscle mass, masseter muscle mass, oral function, and dentition status in older Japanese adults.

BACKGROUND: Generalized loss of skeletal muscle mass (SMM) may modulate or otherwise affect the loss of masseter muscle mass and be responsible for low masseter muscle performance and strength (i.e., low oral function). Moreover, dentition status can affect oral function independent of the muscle state. This cross-sectional study aimed to simultaneously investigate the relationships among whole-body SMM, masseter muscle mass, oral function (masseter muscle performance and strength), and dentition status in 1349 Japanese adults (mean age = 73.6 years). METHODS: We determined the estimated masseter muscle mass (e-MMM) based on morphological measurements of the masseter muscle. Masseter muscle performance was assessed via masticatory performance evaluation scores using gum, and strength was assessed as the maximal occlusal force. Dentition status was assessed as the number of functional teeth. SMM was measured by bioelectrical impedance analysis. Structural equation modeling stratified by sex was employed to investigate associations among SMM, e-MMM, gum score, occlusal force, and number of functional teeth. RESULTS: The direct path from SMM to e-MMM was statistically significant, as was the direct path from e-MMM to oral function (gum score and maximum occlusal force) for both sexes. We additionally confirmed that SMM indirectly affected gum score and maximum occlusal force via e-MMM (men; standardized coefficient [95% CI] = 3.64 [1.31 to 5.96] for maximum occlusal force and 0.01 [0.01 to 0.02] for gum score, women; 2.01 [0.38 to 3.81] for maximum occlusal force and 0.01 [0.002 to 0.01] for gum score). The number of functional teeth had direct effects on e-MMM, gum score, and maximum occlusal force. CONCLUSIONS: Low SMM was significantly indirectly associated with poor oral function through a low masseter muscle mass, and dentition status was independently associated with oral function.

Rate of oral frailty and oral hypofunction in rural community-dwelling older Japanese individuals.

OBJECTIVE: To clarify the rate of oral frailty and oral hypofunction in rural community-dwelling older adults in Japan. BACKGROUND: Recently, the oral function of Japanese older adults has been evaluated multilaterally based on two concepts: oral frailty and oral hypofunction. Oral frailty is defined as a decrease in the oral function accompanied by a decrease in mental and physical functions. Oral hypofunction is a disease where the oral function is comprehensively decreased. However, their rates have not yet been elucidated. MATERIALS AND METHODS: Oral frailty and oral hypofunction were evaluated in 679 older adults from rural areas. To investigate the differences in occurrence rates due to the evaluation methods, one of the subordinate symptoms of oral hypofunction, the reduced occlusal force, was evaluated based on both the occlusal force (main method) and the number of teeth (alternative method). RESULTS: The rate of oral frailty was 22.3% in men and 22.7% in women. The rate of oral hypofunction was 39.0% in men and 46.9% in women. The overall rate of oral hypofunction was 43.6% when the reduced occlusal force of oral hypofunction was evaluated using the main method and 46.4% when evaluated using the alternative method. The proportion of participants with decreased occlusal force, the number of present teeth, oral diadochokinesis, tongue pressure and masticatory performance increased with age in both men and women. CONCLUSION: Among rural community-dwelling older adults, the rate of oral frailty was 22.5% and that of oral hypofunction was 43.6%.

Factors affecting masticatory function of community-dwelling older people: Investigation of the differences in the relevant factors for subjective and objective assessment.

OBJECTIVE: This study aimed to examine relevant factors for subjective and objective assessment of masticatory functions and elucidate any differences between the two methods. BACKGROUND: Previous studies have reported that the results of subjective and objective assessment of masticatory function in older people do not necessarily agree. MATERIALS AND METHODS: This study included 487 community-dwelling Japanese older people (205 male and 282 female; mean age 74.1±6.3 years) who participated in a comprehensive geriatric health examination. Basic information (gender and age), higher level of competence in daily living, depression, subjective masticatory function (SMF) and objective masticatory function (OMF) assessments, cognitive function, skeletal muscle mass, handgrip strength, gait speed and oral status (number of remaining and functional teeth, mouth dryness and occlusal force) were recorded. RESULTS: Multiple logistic regression analysis showed that depression (odds ratio [OR]: 1.181, 95% confidence interval [CI]: 1.094-1.275), mouth dryness (OR: 2.037, CI: 1.212-3.423) and occlusal force (OR: 0.997, CI: 0.996-0.999) were significantly associated with SMF, whereas higher level of competence in daily living (OR: 0.730 CI: 0.586-0.910), skeletal muscle mass (OR: 0.521 CI: 0.283-0.960), number of functional teeth (OR: 0.862 CI: 0.775-0.959), number of remaining teeth (OR: 0.868 CI: 0.810-0.930) and occlusal force (OR: 0.994, CI: 0.991-0.998) were associated with OMF. CONCLUSION: Subjective masticatory functionSMF and OMF were associated with different factors, suggesting that both mental and physical factors should be taken into consideration when treating decreased masticatory function.

The effects of dental visits on the occurrence of acute hospitalization for systemic diseases among patients aged 75 years or older: A propensity score-matched study.

BACKGROUND: Although several studies examined the association between oral status and the risk of systemic diseases, few have examined whether dental visits affect the occurrence of acute hospitalization due to systemic diseases. This study examined the effects of dental visits on preventing the occurrence of acute hospitalization due to systemic diseases in adults aged ≥ 75 years, in order to optimize the healthcare system for older adults. METHODS: This propensity-score-matched retrospective cohort study was conducted using medical insurance claims data from Hokkaido, Japan. We analyzed 432,292 adult outpatients aged ≥ 75 years between September 2016 and February 2017 (baseline period). The exposure variable was visits to the dental office during the baseline period. The primary outcome variable was the occurrence of acute hospitalization due to pneumonia, urinary tract infections, cerebrovascular diseases, or coronary heart diseases between March 2017 and March 2019. RESULTS: Among the 432,292 patients before propensity score matching, 149,639 (34.6%) had visited the dental office. One-to-one propensity score matching produced 149,289 matched pairs adjusted for the differences in all covariables (age, sex, copayment rate, annual health checkup, chronic diseases, and residential area). In these matched pairs, the risk ratio of the occurrence of acute hospitalization due to pneumonia, urinary tract infections, and cerebrovascular diseases was lower among patients who had visited dental office than among those who did not. CONCLUSIONS: Dental visits appeared to be effective in preventing acute hospitalization due to systemic diseases, thus, dental care services would be an important component of healthcare for older adults.

Association between sarcopenia and oral functions in community-dwelling older adults: A cross-sectional study.

BACKGROUND: Few studies have examined the state of oral function in older adults with sarcopenia. We assessed the oral functions of community-dwelling older adults with sarcopenia from multiple perspectives to clarify their potentially low oral function. METHODS: A total of 1517 (86.2%; 990 women, 527 men; mean age 76.1 ± 7.6 years) participants were included in this study. Grip strength, gait speed and skeletal muscle mass index were assessed, and sarcopenia was evaluated according to the criteria of the Asian Working Group for Sarcopenia 2019. The degree of tongue coating, oral moisture, occlusal force, tongue-lip motor function, tongue pressure, masticatory function and swallowing function were assessed. The criteria for oral hypofunction (a disease that is a combination of multiple low oral functions) were used to assess oral function. Statistical analyses were performed using Kolmogorov-Smirnov test, unpaired t-test, Mann-Whitney U test, χ2 test, and univariate and multivariable logistic regression analyses, with each oral function as the dependent variable and sarcopenia as one of the independent variables. The significance level was set at P < 0.05. RESULTS: The prevalence rates of sarcopenia and severe sarcopenia were 14.2% and 3.8%, respectively. The prevalence of oral hypofunction was 39.9%. Compared with the robust group, the sarcopenia and severe sarcopenia groups tended to have a higher frequency of the following components (all P < 0.01): low occlusal force, low tongue-lip motor function, low tongue pressure, low masticatory function, low swallowing function and oral hypofunction. Univariate logistic regression analysis showed that sarcopenia was associated with low occlusal force, low tongue-lip motor function, low tongue pressure, low masticatory function, low swallowing function and oral hypofunction. The odds ratios and 95% confidence intervals of sarcopenia for each oral function were 2.62 [2.00, 3.43], 2.21 [1.69, 2.89], 3.66 [2.79, 4.81], 3.23 [2.46, 4.25], 1.66 [1.26, 2.20] and 3.59 [2.72, 4.72], respectively. Multivariable logistic regression analysis showed that sarcopenia was associated with low occlusal force (1.63 [1.10, 2.40]), low tongue pressure (2.28 [1.65, 3.15]), low masticatory function, (1.94 [1.27, 2.97]), low swallowing function (1.64 [1.17, 2.28]) and oral hypofunction (2.17 [1.52, 3.09]). CONCLUSIONS: This study demonstrated that multiple aspects of oral function were low among community-dwelling older adults with sarcopenia. The potential decline in oral functions in older adults with sarcopenia may have been overlooked until now. This study indicates the need for dental perspectives in intervening with older adults with sarcopenia and the need to encourage them to see dental professionals.

New therapeutic strategy for amino acid medicine: effects of dietary glutamate on gut and brain function.

The gustatory and visceral stimulation from food regulates digestion and nutrient utilization, and free glutamate (Glu) release from food is responsible for the umami taste perception that increases food palatability. The results of recent studies reveal a variety of physiological roles for Glu. For example, luminal applications of Glu into the mouth, stomach, and intestine increase the afferent nerve activities of the glossopharyngeal nerve, the gastric branch of the vagus nerve, and the celiac branch of the vagus nerve, respectively. Additionally, luminal Glu evokes efferent nerve activation of each branch of the abdominal vagus nerve. The intragastric administration of Glu activates several brain areas (e.g., insular cortex, limbic system, and hypothalamus) and has been shown to induce flavor-preference learning in rats. Functional magnetic resonance imaging of rats has shown that the intragastric administration of Glu activates the nucleus tractus solitarius, amygdala, and lateral hypothalamus. In addition, Glu may increase flavor preference as a result of its postingestive effect. Considering these results, we propose that dietary Glu functions as a signal for the regulation of the gastrointestinal tract via the gut-brain axis and contributes to the maintenance of a healthy life.

Impact of number of functional teeth on independence of Japanese older adults.

AIM: To examine the relationship between the number of present and functional teeth at baseline and future incidence of loss of independence. METHODS: Participants were community-dwelling older individuals who participated in a comprehensive geriatric health examination conducted in Kusatsu town, Japan, between 2009 and 2015. The primary endpoint was the incidence of loss of independence among participants, defined as the first certification of long-term care insurance in Japan. The numbers of present and functional teeth at baseline were determined via an oral examination. Demographics, clinical variables (e.g., history of chronic diseases and psychosocial factors), blood nutritional markers, physical functions, and perceived masticatory function were assessed. RESULTS: This study included 1121 individuals, and 205 individuals suffered from loss of independence during the follow-up period. Kaplan-Meier estimates of loss of independence for participants with smaller numbers of present and functional teeth were significantly greater than for those with larger numbers of teeth. Cox proportional hazard analyses indicated that a smaller number of present teeth was not a significant risk factor after adjusting for demographic characteristics. However, the number of functional teeth was a significant risk factor after the adjustment (hazard ratio: 1.975 [1.168-3.340]). Additionally, higher hazard ratios were observed in other adjusted models, but they were not statistically significant. CONCLUSIONS: The number of functional teeth may be more closely related to the future incidence of loss of independence than the number of present teeth. This novel finding suggests that prosthodontic rehabilitation for tooth loss possibly prevents the future incidence of this life-event. Geriatr Gerontol Int 2022; 22: 1032-1039.

Factors associated with masticatory performance in community-dwelling older adults: A cross-sectional study.

BACKGROUND: Decreased masticatory performance leads to deterioration of overall health among older adults. However, maintaining and improving masticatory performance in ways other than maintenance of natural teeth and appropriate prosthodontic treatment remains unclear. If the factors related to the mixing and shearing abilities for masticatory performance are clarified, it may be possible to maintain and improve the masticatory performance of older adults. We aimed to clarify the association among mixing ability, shearing ability, and masticatory performance-related factors. METHODS: Of the 707 community-dwelling older adults in Kusatsu Town, Japan, 344 who had been treated for any dental defects were enrolled in this study. Masticatory performance was evaluated on the basis of mixing ability and shearing ability. The number of natural teeth and artificial teeth, occlusal force, tongue pressure, and oral diadochokinesis /ta/ were measured as masticatory performance-related factors. Their relationship with mixing ability, shearing ability, and masticatory performance-related factors was examined by means of Spearman rank correlation coefficient and path analysis. RESULTS: Among masticatory performance-related factors, the number of natural teeth, occlusal force, and tongue pressure were directly associated with both mixing ability and shearing ability. Moreover, mixing ability was also directly associated with shearing ability. CONCLUSIONS: Tongue pressure, which can be improved by means of training, is a masticatory performance-related factor associated with both mixing and shearing abilities. PRACTICAL IMPLICATIONS: Training for tongue pressure after proper prosthetic treatment may provide an effective means of maintaining and improving masticatory performance in older adults.

Number of functional teeth more strongly predicts all-cause mortality than number of present teeth in Japanese older adults.

AIM: Previous studies on the association between intraoral conditions and mortality in community-dwelling older individuals reported that fewer present teeth (PT) are significant risk factors for mortality. However, how the number of PT relative to the number of functional teeth (FT), including both present and rehabilitated teeth, influences mortality has not been investigated fully. This study examined the impact of the number of FT on mortality among community-dwelling Japanese older adults. METHODS: This study was a retrospective, observational and population-based follow-up study, which examined 1188 older individuals who participated in an annual geriatric health examination from 2009 to 2015. The average follow-up period was 1697.0 ± 774.5 days. The primary outcome was all-cause mortality at follow-up. The numbers of PT and FT of each participant were counted during an oral examination. In addition, demographics, clinical variables, blood nutrient markers, physical functions and perceived masticatory function were measured. RESULTS: Kaplan-Meier analysis, followed by a log-rank test, revealed that fewer PT (P < 0.001) and FT (P = 0.002) were significantly associated with a reduced survival rate. Cox's proportional hazard analysis indicated that the number of FT, but not the number of PT, was a significant independent mortality risk factor after adjusting for demographics, clinical variables, nutrient markers and physical functioning (P = 0.036, hazard ratio: 2.089). CONCLUSIONS: Current results suggest that the number of FT more strongly predicts all-cause mortality than the number of PT among community-dwelling older adults. Further studies are necessary to consider the confounding of socioeconomic status and disability status. Geriatr Gerontol Int 2020; ••: ••-••.