Association Between the Incidence of Early Childhood Caries and Attending Childcare among Toddlers in a Rural Area of Japan: a Prospective Cohort Study

Objective The purpose of this study was to investigate the association between the incidence of early childhood caries (ECC) and factors of the daytime childcare environment among toddlers in a rural area of Japan. Material and methods This was a prospective cohort study. Data collected from 2011 to 2015 were obtained for initially caries-free, 18-month-old toddlers (N = 640). Dentists recorded the numbers of decayed, missing and filled teeth (caries incidence) of toddlers at baseline (age 18 months) and follow-up (age 3 years). In addition, a questionnaire survey was conducted on guardians at baseline to record data on lifestyle. Results In total, 159 (24.8%) toddlers had newly identified ECC at follow-up. Logistic regression analyses indicated that the incidence of ECC was significantly associated with receiving daytime care at a nursery school (odds ratio [OR], 1.55; 95% confidence interval [CI], 1.05-2.30;p = .029), prolonged breastfeeding (OR, 1.71; 95%CI, 1.15-2.55;p = .008), and snacking >= 3 times a day (OR, 2.39; 95%CI, 1.53-3.74;p < .001). Conclusion These findings suggest that receiving daytime care at a nursery school, prolonged breastfeeding, and frequent snacking are associated with an increased risk of ECC among Japanese toddlers in rural areas.