This study examines the association between low-level environmental lead exposure and children's intellectual function, focusing on children with maximal blood lead levels below 10 μg/dL. Data from seven international longitudinal cohort studies were pooled to analyze the relationship between intelligence test scores and blood lead concentration. The primary outcome measure was the full-scale IQ score, which was significantly related to concurrent blood lead levels. The results showed an inverse relationship between blood lead concentration and IQ score, with a 6.9 IQ point decrement associated with an increase in concurrent blood lead levels from 2.4 to 30 μg/dL. The lead-associated IQ decrement was greater for children with maximal blood lead levels below 7.5 μg/dL compared to those with higher levels. The study concludes that environmental lead exposure in children with maximal blood lead levels below 7.5 μg/dL is associated with intellectual deficits, emphasizing the importance of primary prevention to reduce lead exposure.This study examines the association between low-level environmental lead exposure and children's intellectual function, focusing on children with maximal blood lead levels below 10 μg/dL. Data from seven international longitudinal cohort studies were pooled to analyze the relationship between intelligence test scores and blood lead concentration. The primary outcome measure was the full-scale IQ score, which was significantly related to concurrent blood lead levels. The results showed an inverse relationship between blood lead concentration and IQ score, with a 6.9 IQ point decrement associated with an increase in concurrent blood lead levels from 2.4 to 30 μg/dL. The lead-associated IQ decrement was greater for children with maximal blood lead levels below 7.5 μg/dL compared to those with higher levels. The study concludes that environmental lead exposure in children with maximal blood lead levels below 7.5 μg/dL is associated with intellectual deficits, emphasizing the importance of primary prevention to reduce lead exposure.