Perinatal & Pediatric
Prenatal Lead Exposure and Intelligence Across Developmental Stages: A Systematic Review and Meta-analysis Victor Florez-Garcia* Victor Florez-Garcia Florez-Garcia Florez-Garcia Florez-Garcia Florez-Garcia Florez-Garcia Florez-Garcia Florez-Garcia Florez-Garcia Florez-Garcia University of Illinois Chicago
Background: Lead is a well-recognized neurotoxic metal with demonstrated consistent detrimental effects on children’s intelligence quotient (IQ) in the postnatal period. However, there is no such consensus about the effects of prenatal exposures. Aim: We aimed to examine the effect of prenatal lead exposure on children’s intellectual quotient. Methodology: We conducted a systematic review with meta-analysis based on three databases: PubMed (MEDLINE), Web of Science, and Lilacs (Latin American and Caribbean Health Sciences Literature). We included studies where exposure involved biomarkers of lead exposure (e.g., blood, urine, etc.) during the prenatal period, and global IQ assessments were conducted in children aged 5 years or older. We standardized the estimates to linear point estimates. The Risk of Bias (RoB) in Non-randomized Studies of Exposures (ROBINS-E) tool was used to evaluate potential systematic errors. We analyzed the pooled estimates using random effects models, also considering fixed effects models. Pooled effects were examined separately by sex. To assess heterogeneity across studies, we employed the I2 statistic and Cochran’s Q test. Results: Only 7 studies were included in analyses. We found a modest negative association between prenatal Pb and standardized IQ scores (β: -0.06; 95%CI: -0.25, 0.13). This association was stronger in boys (β: -1.08; 95%CI: -3.08, 0.92), yet positive in girls (β: 0.64; 95%CI: -0.31, 1.60), with both results showing high heterogeneity. Conclusion: Results from our study suggest that prenatal lead exposure increases the risk of lower intelligence quotient scores in children 5 years and older. However, research is sparse and more studies are needed to investigate confounding factors and whether the effect varies by sex.