[Study of relationship between prenatal molybdenum exposure and internalizing and externalizing problems in preschool...

Objective: To understand the association of prenatal molybdenum exposure with internalizing and externalizing problems in preschool children and potential sex-specific differences. Methods: A total of 2 514 mother-child pairs were inclided from Ma'anshan Birth Cohort. Maternal peripheral venous blood samples were collected during the first, second, and third trimesters of pregnancy, and neonatal cord blood samples were collected at birth, and serum molybdenum concentrations were measured using inductively coupled plasma-mass spectrometry. The Child Behavior Checklist for age 1.5-5.0 was used to assess children's internalizing and externalizing problems at 4 years old. We converted serum molybdenum concentrations by lg transformation and divided serum molybdenum concentrations into low (<P₂₅), medium (P₂₅-P₇₅), and high (≥P₇₅) level groups according to the distribution of serum molybdenum levels. Binary logistic regression models were used to analyze the association between the exposure to molybdenum and the risk for internalizing and externalizing problems in children. Results: After adjusting for confounders, it was found that the risk for internalizing problems increased in children in serum molybdenum moderate-level group (OR=1.32,95%CI:1.02-1.72) compared with the serum molybdenum low-level group in the whole pregnancy. The serum molybdenum high-level group in neonatal umbilical cord blood (OR=1.72, 95%CI: 1.05-2.82) was associated with the increased risk for externalizing problems in children. The associations between serum molybdenum levels and the risk for childhood internalizing and externalizing problems were not significant in both the first trimester and third trimester of pregnancy (all P>0.05). Sex-stratified analyses showed an increased risk for internalizing problems in boys in the context of the moderate-level (OR=1.84,95%CI:1.26-2.67) and high-level (OR=1.62,95%CI: 1.06-2.49) of serum molybdenum in the whole pregnancy compared with low-level group, but no association was found in girls. Conclusions: Molybdenum level during pregnancy showed significant positive association with the risk for internalizing problems in children, and high level of molybdenum in neonatal umbilical cord blood increased the risk for externalizing problem. Sex-stratified analysis showed that serum molybdenum level during pregnancy showed significant positive association with the risk for internalizing problem in boys.