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).