Tohoku University
Graduate School of Dentistry

Social isolation of older people in Japan is a big problem. But, the association between oral health and being social isolated over time is still unknown. In this study we examined the association among number of teeth and dental prosthesis use with social isolation status after 6 years of follow-up using the data collected for the JAGES study (n=26,417). The results showed that compared to those with 20 or more teeth, those with 10-19 teeth and those with 0-9 teeth were 13% and 36% more likely to be socially isolated after 6 years of follow-up respectively. Also, compared to those who did not use a dental prosthesis, those who used a dental prosthesis were 10% less likely to be socially isolated. When these two oral health measures were combined together, compared to those with 20 or more teeth and regardless of dental prosthesis use, those who had 0-9 teeth and didn’t use a dental prosthesis were 79% more likely to be socially isolated, whereas those with 0-9 teeth and used a dental prosthesis were only 23% more likely to be socially isolated. These results mean that tooth loss was a main predictor for being social isolated at follow-up, while no dental prostheses use was an additional risk factor for social isolation. Also, it means that dental prosthesis use may reduce the risk of social isolation especially in those with severe tooth loss (i.e. more than 23 teeth lost). Preservation of the remaining teeth and providing dental prostheses services could potentially reduce the burden of social isolation among those who are 65 years or older in Japan. (In this study, dental prosthesis=denture or bridge)
※The findings of this study were published on March 30th, 2022, in Community Dentistry and Oral Epidemiology.

Figure 1. Fully adjusted interaction: the logistic regression model examining the interaction between number of remaining teeth and dental prosthesis use on social isolation after adjusting for all confounders (N=26,417)