ADHD and Methylphenidate Use in Prepubertal Children and BMI and Height at Adulthood

Importance: As attention-deficit/hyperactivity disorder (ADHD) is commonly diagnosed in childhood, methylphenidate (MPH) is the most widely prescribed treatment. Although effective for symptom management, concerns remain about an association with growth and body composition. Objective: To investigate the associations of the prevalence of ADHD and MPH use in childhood with body mass index (BMI) and height at adulthood (aged 20 to 25 years). Design, Setting, and Participants: In this nationwide retrospective cohort study, data of children aged 6 to 11 years and adolescents aged 12 to 19 years with newly diagnosed ADHD from the Korean National Health Insurance Service were included between January 2008 and December 2013. Exact matched controls of children and adolescents without ADHD were also included. Their cumulative medication exposure over a 4-year period was assessed, and their height and weight during adulthood were subsequently evaluated from January 2018 to December 2022. Data extraction and statistical analyses were conducted from November 2024 to May 2025. Exposures: Diagnosis with ADHD and MPH prescriptions (cumulative days of MPH use,