Fewer teeth are a risk factor for being underweight in community‐dwelling Japanese aged 40 years and older: The Yamagata (Takahata) Study

Objective The aim of the present study was to investigate comprehensively, the risk factors for underweight in cross‐sectional study in the general population of Japan. Methods The survey population was the general population of individuals aged >40 years in Takahata town, Japan in 2005. A postal survey in the form of a self‐administered questionnaire was distributed, and 6084 individuals were entered into the final statistical analysis. The self‐administered questionnaire contained items regarding lifestyle, oral health status, socio‐economic status and dietary intake. To examine the independent relationships between an underweight status and several parameters, a multivariate logistic regression analysis was used to estimate adjusted odds ratios (ORs). Results The number of teeth, age, alcohol consumption, hypertension, spousal status, smoking habit, appetite, body weight at 20 years of age, habit of going out and physical activity were independently associated with an underweight status compared with the normal weight group. Individuals with fewer than 10 teeth were especially more likely to be underweight than individuals with more than 20 teeth (OR = 1.956, 95% CI = 1.261‐3.035). Conclusion This study showed an independent association between the number of teeth and an underweight status, indicating that fewer teeth can increase the risk of being underweight.