Risk Factors for Early Childhood Caries in Three-Year-Old Japanese Children: A Prospective Cohort Study.

he purpose of this study was to examine risk factors in the development of early childhood caries (ECC) at age three years in a prospective cohort study of 18- to 23-month-old children. This was a longitudinal observational study of 872 children 18 to 23 months of age in Hokkaido, Japan, with follow-up at age three years. A self-administered questionnaire was completed by parents or guardians of the children. The baseline survey contents included sex, age, the existence of smokers in the home, maternal smoking during pregnancy, nocturnal breastfeeding, snacking habits, bottle-feeding, frequency of parents brushing their child's teeth, the use of fluoride toothpaste, parents sharing of utensils with child, and socio-economic status. The number of decayed, missing, or filled teeth (dmft) was obtained from dental examinations in both the baseline and follow-up surveys. Logistic regression analysis was performed to estimate the odds ratio for the new onset of ECC in threeyear-olds. The dmft at 18 to 23 months old, nocturnal breastfeeding, prolonged breastfeeding, snacking habits, parents brushing their child's teeth less frequently, and parental sharing utensils with the child were significantly associated with the incidence of ECC at age three years. The existence of early childhood caries in 18- to 23-month-olds may be a strong predictor of the new development of dental caries. Other lifestyles were found to be risk factors for the incidence of dental caries by age three years.