LEAD exposure during pregnancy is associated with an increase in autistic-like behaviours in children, and this relationship may be mitigated by higher gestational folate levels or folic acid (FA) supplementation, according to recent research. Although lead exposure has been declining, it remains higher among marginalised populations and in low- to middle-income countries, with no safe exposure threshold identified. Prior research has suggested that FA supplementation may reduce the impact of toxic chemical exposure on child neurodevelopment, but its specific role in lead exposure has not been elucidated.
Researchers aimed to assess whether maternal plasma folate levels, FA supplementation, and genetic variants in the methylenetetrahydrofolate reductase (MTHFR) gene modifies the relationship between prenatal lead exposure and autistic-like behaviours in children. Data from 601 mother-child pairs from the Maternal–Infant Research on Environmental Chemicals study were analysed. Blood lead levels (BLLs) and plasma folate concentrations were measured during the first and third trimesters, while child neurodevelopment was assessed at ages 3–4 using the Social Responsiveness Scale-2 (SRS-2). The analysis focused on confounder-adjusted associations between lead exposure and SRS-2 scores, stratified by maternal folate status and MTHFR 677C>T genotype.
The results revealed that higher BLLs during the third trimester were associated with an increase in SRS-2 scores, particularly among children whose mothers had low third-trimester plasma folate levels (β = 3.3; 95% CI: 1.1, 5.5). In contrast, no significant association was observed for mothers with moderate folate levels (β = -0.3; 95% CI: -1.2, 0.5). Furthermore, FA supplementation attenuated the lead-associated increase in autistic-like behaviours. On the other hand, the MTHFR genotype did not significantly modify these associations.
These findings suggest that adequate maternal folate levels and FA supplementation during pregnancy may reduce the neurotoxic effects of prenatal lead exposure on child neurodevelopment. Clinically, ensuring sufficient folate intake, particularly in high-risk populations, may be a valuable strategy to protect against the detrimental effects of lead exposure. Future research should aim to establish optimal supplementation guidelines in lead-exposed populations.
Katrina Thornber, EMJ
Reference
Alampi JD et al. Combined exposure to folate and lead during pregnancy and autistic-like behaviors among Canadian children from the MIREC regnancy and Birth Cohort. Environmental Health Perspectives. 2024;132(10):107003.
