Dietary supplement use is widespread amongst the general population including in children and adolescents. The ingredients in dietary supplements can interact with medicines when patients take them concomitantly. However, the prevalence of the concomitant use of dietary supplements and medicines in Japan among children remains unclear. To clarify this issue, a nationwide internet survey was administered to 55,038 mothers (25 to 60 years old) of preschool- or school-aged children in Japan. Among them, 7.6% currently provide dietary supplements and 3.2% concomitantly provide dietary supplements and prescription or over-the-counter medicines to their children. The prevalence of concomitant use increased with the children's grade. Among 1057 mothers with 1154 children who were concomitantly using dietary supplements and medicines, 69.1% provided dietary supplements without physician consultation because they considered dietary supplements as only foods and therefore safe. Although the purpose of the use and types of dietary supplement differed between boys and girls, the most popular product was probiotics in both boys and girls. Among concomitant users, 8.3% of mothers gave dietary supplements for treatment of diseases and 4.9% mothers recognized the adverse events of dietary supplements in their child. The findings of this study suggest that mothers' knowledge about the risk of using dietary supplement with medicines is insufficient. Parental education about the safety of dietary supplements and potential risk of drug-supplement interaction is needed.
Keywords: adverse event; children; dietary supplements; internet survey; mothers.