Association between the number of existing teeth and maintenance dialysis therapy: A cross-sectional study of adult male dentists.

Dental caries and periodontal disease are typical oral diseases frequently observed in patients with renal diseases. Tooth loss is an outcome of dental caries and periodontal disease, and the number of existing teeth is an indicator of oral health status. However, the association between the number of existing teeth and end-stage kidney disease (ESKD) has not been investigated in detail. This study aimed to investigate the association between oral health status, expressed by the number of existing teeth, and ESKD. We analyzed data from the second survey of the Longitudinal Evaluation of Multi-phasic, Odontological, and Nutritional Associations in Dentists, a cohort study conducted among members of the Japan Dental Association. From August 2016 to July 2017, self-administered questionnaires were mailed to 16,128 male dentists and 8,722 responded. Among them, 7,479 men with complete data on age, number of existing teeth, and ESKD were included in the analysis. Multivariate logistic regression analysis was conducted, with ESKD as the dependent variable and the number of existing teeth (≥23 teeth and <23 teeth) as the independent variable. Subgroup analysis by age (<65 years and ≥65 years) was also conducted. The <23 teeth group had a significantly higher rate of ESKD than did the ≥23 teeth group. After adjusting for age, body mass index, smoking habits, hypertension, and diabetes mellitus, there was no significant association between having <23 teeth and ESKD in all participants. However, the subgroup analysis revealed a significant association after adjustment for covariates in participants aged <65 years but not in those aged ≥65 years. In conclusion, having <23 teeth was associated with the risk of requiring maintenance dialysis therapy among Japanese men aged <65 years. Therefore, tooth loss may be associated with renal function decline.

Effects of oral health-related quality of life on total mortality: a prospective cohort study.

BACKGROUND: The effects of oral health on mortality have been reported; however, the association between mortality and Oral Health-Related Quality of Life (OHQOL) is unknown. We investigated the effect of OHQOL on total mortality in a cohort consisting of dentists. METHODS: In this cohort study, we analyzed data from the Longitudinal Evaluation of Multi-phasic, Odonatological and Nutritional Associations in Dentists study. We conducted a baseline survey of general and oral health factors. We called for 31,178 participants and collected responses from 10,256 participants. We followed up with 10,114 participants (mean age ± standard deviation, 52.4 ± 12.1 years; females, 8.9%) for 7.7 years, until March 2014, to determine the average total mortality. OHQOL was assessed using the General Oral Health Assessment Index (GOHAI). The total score was divided into quartiles (Q1 ≤ 51.6, Q2 = 51.7-56.7, Q3 = 56.8-59.9, and Q4 = 60.0), with higher GOHAI scores indicating better OHQOL (score range, 12-60). The association between OHQOL and total mortality was analyzed using the Cox proportional hazards model. RESULTS: We documented 460 deaths. Males with low GOHAI scores possessed a remarkably high risk of total mortality. The multivariate adjusted-hazard ratios (aHRs), were 1.93 (95% confidence interval [CI], 1.07 - 3.48) for Q1, 1.69 (95% CI, 0.90 - 3.17) for Q2, and 0.65 (95% CI, 0.29 - 1.46) for Q3, relative to Q4 (trend p = 0.001). The aHRs in the multivariate model with all background variables were 1.69 (95% CI, 1.15-2.46) for Q1, 1.53 (95% CI, 1.04-2.27) for Q2, and 1.09 (95% CI, 0.71-1.70) for Q3, relative to Q4 (trend p = 0.001). In females, there was no significant association between the quartiles, in both the multivariate-adjusted model (trend p = 0.52) and multivariate-adjusted model with all background variables (trend p = 0.79). CONCLUSIONS: A lower OHQOL indicated an increased risk of total mortality in dentists. OHQOL may be used as an indicator for selecting treatment plans and personalized care interventions, thus contributing to increased healthy life expectancy. TRIAL REGISTRATION: Aichi Cancer Center, Nagoya University Graduate School of Medicine, and Hiroshima University (Approval numbers: 33, 632-3, 8-21, and E2019-1603).

Tooth brushing, tooth loss, and risk of upper aerodigestive tract cancer: a cohort study of Japanese dentisits.

Previous studies have focused on the association between poor oral health and upper aerodigestive tract (UADT) cancer. However, whether toothbrushing and tooth loss are associated with UADT cancer risk is still unclear. Therefore, we investigated the association between toothbrushing or tooth loss and UADT cancer in the Longitudinal Evaluation of Multi-phasic, Odontological, and Nutritional Associations in Dentists (LEMONADE) cohort study. From 2001 to 2006, we recruited 20,445 dentists (mean age ± standard deviation, 51.8 ± 12.0 years; 1,607 women [7.9%]) and followed for incidence or mortality of UADT cancer through March 2014. Information on lifestyle and oral health was collected by the baseline questionnaire. The Cox proportional hazards model was used to estimate hazard ratios (HRs) for UADT cancer and corresponding 95% confidence intervals (CI) for brushing frequency and tooth loss with adjustment for covariates. During the mean follow-up of 9.5 years, we confirmed 62 incident or fatal cases of UADT cancer. Infrequent toothbrushing (< 2 times/day) was significantly associated with increased risk of UADT cancer (multivariate HR = 2.13, 95% CI: 1.04-4.37). On the contrary, tooth loss was not significantly correlated with UADT cancer risk; multivariate HR was 1.03 (95% CI: 0.41-2.61) for loss of 15-27 teeth and 1.37 (0.50-3.75) for that of 28 teeth compared to tooth loss of 0-14 teeth. In conclusion, Infrequent toothbrushing was significantly associated with the risk of UADT cancer.

Tooth loss and pneumonia mortality: A cohort study of Japanese dentists.

Although associations between oral health and pneumonia have been reported in previous studies, particularly in the institutionalized elderly, few prospective studies have investigated the association between oral condition and pneumonia among community-dwelling people and whether the findings among inpatients or patients in nursing homes are applicable to the general population is still unclear. The oral bacteria propagated in the periodontal regions may drop into the lung and increase the risk of pneumonia. We, therefore, investigated the association of tooth loss with mortality from pneumonia in a cohort study of Japanese dentists. Members of the Japan Dental Association (JDA) participated in the LEMONADE (Longitudinal Evaluation of Multi-phasic, Odontological and Nutritional Associations in Dentists) Study. From 2001 to 2006, they completed a baseline questionnaire on lifestyle and health factors including the number of teeth lost (excluding third molars). We followed 19,775 participants (mean age ± standard deviation, 51.4 ± 11.7 years; 1,573 women [8.0%] and 18,202 men [92.0%]) for mortality from pneumonia (ICD-10, J12-J18). Mortality data were collected via the fraternal insurance program of the JDA. The hazard ratios (HRs) were estimated with adjustment for sex, age, body mass index, smoking status, physical activity and diabetes history. During the median follow-up period of 9.5 years, we documented 68 deaths from pneumonia. Participants who were edentulous at baseline were at significantly increased risk of mortality from pneumonia. The multivariable-adjusted HRs were 2.07 (95% confidence interval [CI], 1.09-3.95) for the edentulous and 1.60 (95% CI, 0.83-3.10) for loss of 15-27 teeth relative to loss of 0-14 teeth (trend p = 0.026). The HR per one tooth loss was also significant; 1.031 (95% CI, 1.004-1.060). In conclusion, a large number of teeth lost may indicate an increased risk of mortality from pneumonia in community-dwelling populations.

Tooth loss and risk of hip fracture: a prospective study of male Japanese dentists.

OBJECTIVES: To determine whether the number of teeth lost can predict the risk of subsequent hip fracture. METHODS: We followed up 9992 male Japanese dentists aged 50 years or more (mean age ± standard deviation [SD], 61.1 ± 9.6 years) for incidence of hip fracture. From 2001 through 2006, they completed a baseline questionnaire on lifestyle and health factors including the number of teeth lost (excluding third molars). Incidence rate ratios (IRRs) were estimated by fitting proportional hazard models. RESULTS: During the mean follow-up period of 6.0 years, 20 new cases of hip fracture occurred. Participants who had lost 15 or more teeth at baseline were at a significantly increased risk of hip fracture: the multivariate-adjusted IRRs were 4.1 (95% confidence interval [CI], 1.2-14.2) for loss of 15-27 teeth and 4.5 (1.1-18.0) for edentulousness relative to loss of 0-14 teeth (trend P, 0.028). Overall, the risk of hip fracture was weakly associated with the number of teeth lost: the IRR per tooth was 1.06 (95% CI, 1.01-1.12). CONCLUSIONS: Tooth loss was slightly associated with a higher risk of subsequent hip fracture. The number of teeth lost might be informative in predicting this risk.

Application of optical coherence tomography (OCT) to nondestructive inspection of dentures.

The porosity of denture base resins continues to be one of the undesirable characteristics of acrylic resins. It is commonly accepted that porosity of the denture not only often leads to denture fractures, but also may function as a reservoir of potential pathogens. The purpose of this study was to present the first OCT images of finished dentures using a new advanced-type OCT scanner we have developed, and to discuss the application of our new OCT system for nondestructive inspection of dentures. Ten newly fabricated full dentures of outpatient of the National Center for Geriatrics and Gerontology in Japan were selected for this study. Two types of denture base resins were used for inspection by OCT, which provided clear images of all the dentures examined. Internal structures, not visually detectable, inspection, can be observed using this OCT system. It is concluded that OCT can detect nonvisible internal structures in dentures, a finding not reported to date. OCT may, therefore, be an appropriate method for detecting interior defects in dentures nondestructively.

Tooth loss and intakes of nutrients and foods: a nationwide survey of Japanese dentists.

OBJECTIVES: To clarify the association of tooth loss with dietary intakes among dentists, for whom sufficient dental care is available. METHODS: We analyzed the data from 20 366 Japanese dentists (mean age +/- SD, 52.2 +/- 12.1 years; women 8.0%) who participated in a nationwide cohort study from 2001 to 2006. The baseline questionnaire included a validated food-frequency questionnaire to estimate intakes of foods and nutrients. We computed the geometric means of daily intakes by the number of teeth, adjusting for age, sex, smoking, physical activity, and history of diabetes. RESULTS: The mean intakes of some key nutrients and food groups, such as carotene, vitamins A and C, milk and dairy products, and vegetables including green-yellow vegetables, decreased with the increasing number of teeth lost (P for trend <0.05). On the contrary, mean intakes of carbohydrate, rice, and confectioneries were increased among those with fewer teeth (P for trend <0.05). The difference in the geometric mean (%) between totally edentulous subjects and those with > or =25 teeth, that is [(Geometric mean for > or =25 teeth) - (Geometric mean for 0 teeth)]/(Geometric mean for > or =25 teeth) x 100, was 14.3%, 8.6%, 6.1%, and -6.1% for carotene, vitamin C, vitamin A, and carbohydrate, respectively. For food groups, it was 26.3%, 11.9%, 5.6%, -9.5%, and -29.6% for milk and dairy products, green-yellow vegetables, total vegetables, rice, and confectioneries, respectively. CONCLUSIONS: Tooth loss was linked with poorer nutrition even among dentists.

Oral care help to maintain nutritional status in frail older people.

The purpose of this study was to evaluate the effect of continuous oral care on the nutritional status of older people who require care using a 1-year randomized, controlled study. Fifty-three residents of a nursing home in Japan participated in this study. Subjects were randomly divided into two groups, an oral care intervention group and control group. The subjects in the oral care intervention group received professional oral care from a dentist three times a week over the course of 1 year. Body weight, body mass index (BMI), serum albumin, and high-density lipoprotein cholesterol (HDL-C) were measured as objective indicators of nutritional status at baseline and after 1 year, and compared between the groups. In the oral care group, no significant decline was seen in all indicators from the start to the end of the intervention, but in the control group there was a statistically significant decline in all indicators at the end of the year. These results suggest that the intervention of oral care alone can serve to maintain the nutritional status of older people who require care. Implementation of continuous oral care is an important task from the viewpoint of maintaining nutritional status in older people.

Longitudinal Evaluation of Multi-phasic, Odontological and Nutritional Associations in Dentists (LEMONADE Study): study design and profile of nationwide cohort participants at baseline.

BACKGROUND: To examine the association between oral health and general well-being, we are currently conducting a nationwide cohort study comprising members of the Japan Dental Association (JDA). Herein, we describe the study design and the profile of the participants at baseline. METHODS: From 2001 through 2006, the participants completed a baseline questionnaire that surveyed factors related to lifestyle, general health, and oral health. Morbidity and mortality have been monitored by using information from fraternal insurance programs operated by prefectural dental associations. All respondents provided written, informed consent for participation and the use of their insurance data. RESULTS: A total of 21,272 JDA members participated in the baseline survey (response rate, 36.2%). Their mean age +/- SD was 52.3 +/- 12.3 years; 8.0% were women. Among the respondents, 30.2% of men and 10.7% of women were current smokers; 73.5% of men and 44.8% of women were current drinkers. The cohort scored higher on oral health indices than did the general Japanese population: dentists were more likely to brush their teeth > or =3 times/day, to have > or =20 teeth, to have fewer lost teeth, to be free from periodontal diseases, and to have higher General Oral Health Assessment Index scores. There was, however, considerable inter-individual variation in scores on the indices. CONCLUSIONS: More than one-third of JDA members participated in the study. Their oral average health status was better than that of the general population. Nevertheless, it will be possible to compare morbidity and mortality between those with better and worse scores on oral health indices.

Relationship between oral function and general condition among Japanese nursing home residents.

The purpose of this study was to clarify the relationship between oral function and general condition among Japanese nursing home residents. The hypothesis was that oral function is one of the most important factors for the maintenance of general condition in dependent elderly. Seventy-nine residents of a nursing home in Japan participated in this study (54 women and 25 men, age range: 65-95 years, mean age: 82.2+/-8.5). A water drinking test and gargling function were used as indicators of oral function. Indicators of general condition included cognitive function (mini-mental state examination; MMSE), ADL (Barthel index), and nutritional status (body mass index=BMI, and serum albumin level). To clarify the relationship between oral function and general condition among dependent elderly, statistical evaluations of correlations (Spearman rank correlation coefficient) and differences (Mann-Whitney U test, Student's t test) between groups were conducted. SPSS was used for the statistical analysis. The water drinking and gargling function tests showed a strong correlation (p<0.001) with cognitive function and ADL. The water drinking and gargling function tests showed a correlation with BMI (p<0.005, p<0.01, respectively), and the water drinking test showed a correlation with serum albumin level (p<0.05). However, no correlation was observed between the gargling function tests and serum albumin level. It is concluded that oral function is closely related to cognitive function, ADL, and nutritional status. Oral function may play an important role in maintaining general condition in dependent elderly. To prevent decreases in cognitive function, ADL and nutritional status in dependent elderly, the importance of improvements in oral function cannot be over-emphasized.