Risk factors for tooth loss in community-dwelling Japanese aged 40 years and older: the Yamagata (Takahata) study

Clin Oral Investig. 2019 Apr;23(4):1753-1760. doi: 10.1007/s00784-018-2604-x. Epub 2018 Aug 30.


Objectives: The aim of the present study was to investigate comprehensively the risk factors, including some lifestyle-associated factors, oral health habits, and socioeconomic status, for having less than 20 teeth in cross-sectional study in the general population of Japan.

Materials and methods: The survey population was the general population of individuals aged greater than or equal to 40 years in Takahata town, Japan in 2005. A postal survey with a self-administered questionnaire was distributed, and 7542 participants were entered into the final statistical analysis. The self-administered questionnaire contained items regarding some lifestyle-associated factors, oral health, and dietary intake, including alcohol and sucrose consumption. To confirm the independent association between the number of teeth and several parameters, a multivariate logistic regression analysis was used to estimate the adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs).

Results: A low educational status, no dental check-ups, low frequency of brushing, older age, and smoking habit were independent risk factors for less than 20 teeth. A low educational status was a particularly significant risk factor for less than 20 teeth (OR = 1.352, 95% CI = 1.125-1.624).

Conclusion: These results emphasize the importance of good oral health habits, such as frequent tooth brushing, routine dental check-ups, and no smoking, and indicate that more appropriate and compulsory education regarding oral health is needed to lessen the education level-derived differences in oral health.

Clinical relevance: Poor oral health habits and low educational status are the independent risk factors for having less than 20 teeth.

Keywords: Cross-sectional study; Educational status; General population; Multivariate logistic regression analysis; Number of teeth; Oral health habits.

MeSH terms

  • Adult
  • Aged
  • Cross-Sectional Studies
  • Diet
  • Female
  • Humans
  • Japan
  • Life Style
  • Male
  • Middle Aged
  • Oral Health*
  • Risk Factors
  • Tooth Loss / epidemiology*