​CopenSleep is a large prospective cohort study investigating sleep patterns and their impact on health and development in children aged 0–17 years. Both healthy children and those with chronic diseases (neurological, metabolic, and structural) will be followed annually with repeated in-depth assessments. We will combine questionnaires, actigraphy, polysomnography, MRI, stress biomarkers, and cognitive testing to characterize sleep architecture and sleep microstructure. The study will establish normative data and describe sleep development across childhood and adolescence.

It will assess prevalence and consequences of sleep-wake disturbances among children with and without chronic diseases. Analyses will link sleep quality to cognitive, mental, social, and physical wellbeing as well as family functioning. Sleep biomarkers will be explored as predictors of neuropsychiatric and medical outcomes. The cohort will include ~300 children with chronic diseases and ~300 healthy siblings or classmates of patients or siblings, with annual follow-up over three years. Findings are expected to improve early detection, intervention, and long-term outcomes in pediatric sleep and health.​​​