Essential trace elements such as zinc (Zn), iron (Fe), and copper (Cu) play a critical role in neurodevelopment, influencing key processes like neurotransmitter regulation and neuronal signaling. To synthesize the existing evidence, we conducted a systematic review and meta-analysis of case–control studies investigating the associations between these trace elements and Attention-Deficit/Hyperactivity Disorder (ADHD) in children and adolescents. A comprehensive literature search was performed up to March 2026 across multiple databases, including Web of Science, PubMed, and the Chinese National Knowledge Infrastructure. A total of 46 studies involving 5515 ADHD cases and 8166 controls were included. The results showed that Zn (SMD = −1.01, 95% CI: −1.51 to −0.52), Fe (SMD = −0.82, 95% CI: −1.52 to −0.11) and Ferritin (SMD = −0.54, 95% CI: −1.00 to −0.27) levels were significantly lower in children with ADHD than in controls, while no significant difference was observed for Cu levels (SMD = −0.55, 95% CI: −1.12 to 0.02). When the research subjects are limited to children ≤12 years old, the differences in Zn are more pronounced. Moreover, the differences in the levels of Zn, Fe, and Cu were more pronounced among children and adolescents from developing countries. These findings suggest that imbalances in Zn and Fe may be involved in the pathogenesis of ADHD. Further research is needed to validate early biomarkers of ADHD risk and to explore their potential application in clinical diagnosis and management, especially considering the high heterogeneity of the studies included in this study.

INPLASY202130056 Maternal anxiety and children’s physical growth: A systematic review and meta-analysis Keywords: anxiety; pregnancy; birth; physical growth. Download PDF – 202130056

Background: Epidemiological studies have identified maternal antenatal anxiety and adverse birth outcomes, but absence of epidemiological studies has examined the relationship with long term physical growth in children. Methods: 3,154 mother-child pairs were included based the Ma’anshan birth cohort study. Maternal prenatal anxiety was obtained by administering a questionnaire using the pregnancy-related anxiety questionnaire (PRAQ) scale during the 1st, 2nd and 3rd trimester. Body fat (BF) and body mass index (BMI) were collected on children from birth to 72 months. Group-based trajectory models were applied to fit the different trajectories of BMI and BF. Results: Maternal anxiety in the 2nd (OR = 0.81; 95% CI: 0.68 to 0.98) and 3rd (OR = 0.82; 95% CI: 0.68 to 0.98) trimester was associated with a decreased risk of RWG in the first year of life. Children aged at 48 to72 months of mothers with anxiety in the 3rd trimester had lower BMI (β = -0.145; 95% CI, -0.279 to -0.011) and BF (β = -0.194; 95% CI, -0.340 to -0.048), and these children were less likely to develop a very high BMI trajectory (OR = 0.59; 95% CI: 0.37 to 0.93), and a high BF trajectory (OR = 0.71; 95% CI: 0.52 to 0.98). A similar association was found between maternal anxiety simultaneously in the 2nd and 3rd trimesters and child physical growth. Conclusions: Maternal prenatal anxiety in the 2nd and 3rd trimester may decrease weight status in preschool-aged children, which may be related to reduced weight gain in infancy resulting in.