A longitudinal study of the relationship between diet intake and dental caries and periodontal disease in elderly Japanese subjects

We hypothesise that a difference in nutrition influences dental caries and periodontal disease. There are few previous studies especially longitudinal ones which have evaluated this hypothesis. This study investigated the relationship between nutritional intake, including milk and milk products (MMP), and dental disease, controlling for several confounding factors. A group of 600 subjects aged 70, randomly selected for this study, included approximately the same number of male and female subjects. The number of teeth on which root caries had occurred or where there was a periodontal event over a 6-year period was measured. To determine quantitative food intake at baseline, a semi-quantitative food frequency questionnaire was used during face-to-face interviews by dieticians. The stepwise method of multiple linear regression analysis was used to identify independent predictors of the number of root caries or periodontal disease events during the 6 years. Intake of the six food groups includes (i) fish, shellfish, meat, beans and eggs; (ii) MMP; (iii) dark green and yellow vegetables (DYV); (iv) other vegetables and fruits; (v) cereals, nuts and seeds, sugar and sweeteners, confectioneries (CNSC) and (vi) fats and oils. The alcohol, gender and anthropometric evaluation including measurements of weight and height for the calculation of body mass index, educational level, the number of family members and the number of remaining teeth were used as independent variables. According to stepwise multiple regression analysis, two variables (quantity of MMP, and gender) were negatively associated with the number of root caries events during the 6 years. The standardised coefficients were -0.14 (p = 0.035) and -0.17 (p = 0.007) respectively. In addition, DYV were negatively, and three other variables (CNSC; alcohol; and the number of remaining teeth at baseline) were positively associated with the number of periodontal disease events during the 6 years. The standardised coefficients were -0.16 (p = 0.001), 0.11 (p = 0.042), 0.10 (p = 0.041) and 0.58 (p < 0.001) respectively. Our results suggest that the intake of MMP in this elderly population correlated with root caries events. In addition, intake of vegetables negatively correlated, and intake of 'CNSC' positively correlated with periodontal disease events.