The association between prenatal maternal selenium concentration and mental health in early childhood, a mother-child cohort study

Background Adequate selenium (Se) status is important for biological mechanisms involved in cognitive functioning and mental health. However, there are few studies that have examined the association between prenatal maternal Se and mental health of preschool children in low-and middle-income countries. The primary aim of this study was to measure associations between maternal plasma Se concentration during pregnancy and child mental health at four years. The secondary aim was to assess the psychometric properties of the parent reported Nepalese version of the Strengths and Difficulties Questionnaire (SDQ-P). Method A total of 720 mother-infant dyads were included in the study from a cohort from Bhaktapur, Nepal, with prenatal maternal plasma Se concentration measured in early pregnancy. Child mental health was assessed at 4 years of age by the SDQ-P. The fit of the original five-factor structure of the SDQ-P was examined using Confirmatory Factor Analysis (CFA). Generalized linear models were used to analyze the association between maternal plasma Se concentration (continuous, dichotomized or tertiles) and child’s SDQ-P scores using the five-factor model. Results The mean (SD) maternal plasma Se concentration was 74.7 µg/L (± 10.2 µg/L). The original five-factor structure of the SDQ-P was confirmed with some modifications (Comparative fit index (CFI)=0.967, Root mean square error of approximation (RMSEA)=0.059). Children with mothers with the lowest tertile of maternal plasma Se concentration had higher Hyperactivity-Inattention scores than those in the middle tertile (adjusted β = 0.329, 95% CI 0.023 to 0.636). No associations were observed between maternal plasma Se concentration and the other SDQ-P subscale scores. Conclusion We observed limited evidence of an association between maternal plasma Se concentration and mental health outcomes in children at 4 years of age. The observed association between maternal plasma Se concentrations and Hyperactivity-Inattention was only present when comparing the lowest to middle tertile, however no clear exposure-response pattern was observed. This isolated finding requires confirmation in further studies.