Bruxism associated with short sleep duration in children with autism spectrum disorder: The Japan Environment and Children’s Study

Bruxism, the involuntary activity of masticatory muscles, is common among individuals with autism spectrum disorders (ASD). Although bruxism is bidirectionally associated with sleep issues, whether an infant's sleep duration contributes to the development of bruxism remains unknown. In this study, a dataset (n = 83,720) obtained from the Japan Environment and Children's Study, a nationwide birth cohort study, was subjected to multiple imputations using logistic regression analysis with adjustments for several maternal and child-related variables. The aim of this study was to assess whether shorter sleep duration in the neonatal period additively affected the high prevalence of parent-reported bruxism (PRB) among children with ASD. The prevalences of ASD and PRB in the participants were 1.2% and 7.2%, respectively, and the odds ratio of the increased risk of PRB prevalence in individuals with ASD (95% confidence interval) was 1.59 (1.31-1.94) after covariate adjustments. Importantly, shorter sleep duration in the neonatal period (at one month of age) was significantly associated with an increased risk of PRB prevalence in individuals with ASD. The increased occurrence of bruxism, known to be highly prevalent among children with ASD, is associated with shorter sleep duration, particularly in the neonatal stage. Based on our results, a better understanding of the development of bruxism in individuals with ASD would provide valuable information for the prevention of oral diseases.