Impact of shared storybook reading on child development: The Japan Environment and Children’s Study

BACKGROUND: Shared storybook reading in early childhood is crucial for cognitive and social development, but its association with broader developmental domains is less established. This study aimed to investigate the association between the frequency of shared storybook reading and overall child development. METHODS: This study analyzed data from the Japan Environment and Children's Study, a nationwide prospective birth cohort study. The frequency of shared storybook reading was assessed at multiple time points up to age 3. Child development was assessed using the Ages and Stages Questionnaire-3 (ASQ-3). The association was analyzed using multivariate models adjusted for parental background, opportunities to play with the child, and media exposure. RESULTS: A total of 36,866 mother-child pairs were analyzed. The frequency of storybook reading positively correlated with the ASQ-3 scores across all developmental domains. After adjustments, frequent reading at age 3 was associated with a 5.5-point increase (95% CI: 5.0-6.0, p < 0.001) in communication scores compared to rare reading. Among children whose ASQ-3 scores fell below the cutoff at the age of 1 year, more frequent reading at subsequent ages was associated with greater score improvements. CONCLUSION: Frequent shared storybook reading positively correlated with the overall developmental progress in early childhood. IMPACT: Based on a large-scale nationwide birth cohort study, frequent shared storybook reading is positively associated with the overall developmental progress in early childhood. Even for children with developmental delays at age one, continuous reading was positively associated with their development.