Gut microbiota and temperament in preschool children

This study investigates the relationship between the composition and diversity of gut microbiota and temperament in preschool-aged children.This study is part of a research project in Japan entitled The Principle of Human Social Brain-Mind Development. Participants were recruited from nursery schools throughout Japan that agreed to participate in the study. Written informed consent was obtained from the mothers of children. This study was approved by the Medical Ethics Committee of Kyoto University (no. R2624) and registered in the UMIN system (UMIN000043945).Mothers collected stool samples from children and completed questionnaires at home (e.g. temperament, socioeconomic status). We collected data on Japanese children aged 0-4 years between January and February 2021. A total of 293 children aged 3-4 completed both the stool collection and temperament questionnaires. We excluded nine children for the following reasons: (1) no answer to all or most of the following questions (socioeconomic status, antibiotic use within the last three months, mother's psychiatric history); (2) their mother had a psychological disease under medical treatment or was taking medication related to psychiatric disorders. Finally, we analysed 284 children (mean age = 46.44 months, SD = 6.27, 172 boys and 112 girls).