Effects of Blood Lead Levels

Abstract

Lead exposures among school-age children are a major public health issue. Although the harmful effects of lead exposure during the first years of life are well known, there is not as much understanding of the effects of low levels of lead exposure during later childhood. To review the effects of blood lead levels (BLLs) <10 µg/dL in school-age children and adolescents. We searched Medline, Embase, Global health, CINAHL, Scopus, and Environmental Science Collection databases between January 1, 2000, and May 11, 2023. We included peer-reviewed English-language articles that presented data on the effects of BLLs <10 µg/dL in individuals ages 5 through 18 years. Data on country, population, analytic design, sample size, age, BLLs, outcomes, covariates, and results were extracted. Overall, 115 of 3180 screened articles met the inclusion criteria. The reported mean or median BLL was <5 µg/dL in 98 articles (85%). Of the included articles, 89 (77%) presented some evidence of an association between BLLs <10 µg/dL during school age and detrimental outcomes in a wide range of categories. The strongest evidence of an association was for the outcomes of intelligence quotient and attention-deficit/hyperactivity disorder diagnoses or behaviors. Few articles controlled for BLLs at age <5 years, limiting conclusions about the relation between later BLLs and outcomes. BLLs <10 µg/dL in school-age children and adolescents may be associated with negative outcomes. This review highlights areas that could benefit from additional investigation.