Breastfeeding and children’s sleep duration at 1 year of age: A nationwide birth cohort - The Japan Environment and Children’s Study

BACKGROUND: Breastfeeding plays a vital role in preventing childhood infections and enhancing many aspects of long-term health. In this study, we investigated the link between feeding and sleep duration and considered the underlying mechanism of the observed effects, particularly the role of nutrients in breast milk and formula as well as that of the brain-gut axis. Few studies have examined the relationship between breastfeeding and infant sleep, and thus there is a need for a prospective study involving a large population. SUBJECTS: This study analyzed data on 82,918 mother-infant pairs from the Japan Environment and Children's Study, a nationwide birth cohort study. We examined the association of breastfeeding pattern over the first 6 months of life by comparing sleep duration at 1 year of age between babies exclusively formula-fed for 6 months and those breastfed for <6 months, those breastfed for 6 months with formula, and exclusively breastfed for 6 months. RESULTS: The adjusted odds ratio (95% confidence interval) for short sleep duration (<11 h/day) at 1 year of age was 0.84 (0.73-0.97) for breastfed for <6 months, 0.79 (0.69-0.91) for breastfed for 6 months with formula, and 0.77 (0.67-0.89) for exclusively breastfed for 6 months compared with exclusively formula-fed for 6 months (Formula alone). CONCLUSIONS: Breastfeeding during the first 6 months of life was associated with a decreased risk of short sleep duration in 1-year-old infants.