PTH and Osteopenia: The long-term use of valproic acid has no significant effect on serum calcium, phosphorus, ALP, PTH, and osteocalcin in children with epilepsy, but it can cause a decrease of 25-OH-VitD and BMD, suggesting that children with epilepsy who had taken valproic acid for a long time have a risk of osteopenia, but multiple centers and large sample data are still needed to look for specific indicators of early bone damage.