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

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