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.