High birthweight is associated with increased prevalence of dental caries in Japanese children

We determined the prevalence of dental caries in 3-year-old Japanese children in a cross-sectional study and analysed its associations with birthweight, gestational age and birthweight for gestational age among the study subjects.Study subjects were 6327 children. Their parents or guardians completed our study questionnaire with information on birth conditions and oral examinations taken from their Maternal and Child Health Handbooks, as documented by medical personnel at the hospital, clinic or public health centre. Children with one or more primary teeth that had either decayed or been filled were categorized as having caries.The prevalence of dental caries was 14.7%. We found a significant association between high birthweight (≥4000 g) and a higher prevalence of caries, compared with normal birthweight (2500-3999 g). Low birthweight (<2500 g) was not associated with dental caries prevalence. In addition, no measurable associations between gestational age or birthweight for gestational age and caries prevalence were observed.Our findings indicate that high birthweight might increase the likelihood of dental caries in children.