Systematic Review-Meta Analysis Study the Effect of Cadmium and Copper Exposure on Children’s Cognitive

Abstract Childhood neurodevelopment could be affected by various factors, such as heavy metal cadmium and copper. The aim of this study was to analyze the scientific evidence published to date on the potential effects on cognitive development in children exposed to cadmium and copper by pooling the results of the different studies. We conducted a systematic review and meta-analysis of original articles published from January 2012 until December 2020 in PubMed, Medline, and Cochrane which evaluate the effects on cognitive development due to pre or post-natal exposure to cadmium and copper in children. Meta-analysis was performed using Revman 5.3 and linear regression techniques were used to estimate the effect size. Publication bias was evaluated by Begg’s and Egger’s tests. Our search resulted in 6 articles that evaluated the effects of cadmium and copper on cognitive development met the inclusion criteria: 4 cadmium, 2 copper, and 1 both. Most studies evaluating cadmium exposure (4 of 5) reported a significant negative effect on cognitive development. Only two studies that evaluated exposure to copper found an association with neurodevelopment. The meta-analysis showed an increase of cadmium levels in urine would be associated with a 1.4 decrease in the full-scale intelligence quotient (IQ) (P =0.008) and a 1.03 decrease in verbal scale IQ of children (P =0.006). There were no enough studies of copper exposure to conduct a meta-analysis. Current evidence supports the finding that cadmium exposure has a detrimental effect on cognitive development in children but there is little information on copper. Keywords: Cadmium, Child, Cognitive, Copper, Neurodevelopment