Declining blood lead levels and changes in cognitive function during childhood - The Port Pirie Cohort Study

dc.contributor.authorTong, S.
dc.contributor.authorBaghurst, P.
dc.contributor.authorSawyer, M.
dc.contributor.authorBurns, J.
dc.contributor.authorMcMichael, A.
dc.date.issued1998
dc.description.abstractContext.— Many studies have found a significant inverse association between early exposure to environmental lead and cognitive function in childhood. Whether these effects are reversible when exposure is reduced is not clear. Objective.— To assess the reversibility of the apparent effects of lead on cognitive abilities in early childhood by testing whether declines in blood lead concentrations beyond the age of 2 years are associated with improvements in cognition. Setting.— Urban and rural communities surrounding a large lead smelter in Port Pirie, South Australia. Participants.— A total of 375 children followed up from birth to the age of 11 to 13 years. Design.— Long-term prospective cohort study. Main Outcome Measures.— The Bayley Mental Development Index at age 2 years, the McCarthy General Cognitive Index at age 4 years, and IQs from the Wechsler Intelligence Scale (revised version) at ages 7 and 11 to 13 years. Results.— Mean blood lead concentrations in the children decreased from 1.02 µmol/L (21.2 µg/dL) at age 2 years to 0.38 µmol/L (7.9 µg/dL) at age 11 to 13 years, but cognitive scores in children whose blood lead concentration declined most were generally not improved relative to the scores of children whose blood lead levels declined least. Changes in IQ and declines in blood lead levels that occurred between the ages of 7 and 11 to 13 years (r = 0.12, P = .09) suggested slightly better cognition among children whose blood lead levels declined most. Conclusion.— The cognitive deficits associated with exposure to environmental lead in early childhood appear to be only partially reversed by a subsequent decline in blood lead level.
dc.description.statementofresponsibilityShilu Tong, Peter A. Baghurst, Michael G. Sawyer, Jane Burns, Anthony J. McMichael
dc.identifier.citationJournal of the American Medical Association (JAMA), 1998; 280(22):1915-1919
dc.identifier.doi10.1001/jama.280.22.1915
dc.identifier.issn0098-7484
dc.identifier.issn1538-3598
dc.identifier.orcidSawyer, M. [0000-0002-7834-0561]
dc.identifier.urihttp://hdl.handle.net/2440/6520
dc.language.isoen
dc.publisherAmerican Medical Association (AMA)
dc.rights© 1998 American Medical Association
dc.source.urihttps://doi.org/10.1001/jama.280.22.1915
dc.subjectHumans
dc.subjectLead Poisoning
dc.subjectLead
dc.subjectRegression Analysis
dc.subjectCohort Studies
dc.subjectLongitudinal Studies
dc.subjectProspective Studies
dc.subjectCognition
dc.subjectCognition Disorders
dc.subjectIntelligence Tests
dc.subjectEnvironmental Exposure
dc.subjectChild
dc.subjectChild, Preschool
dc.subjectInfant
dc.subjectInfant, Newborn
dc.subjectSouth Australia
dc.titleDeclining blood lead levels and changes in cognitive function during childhood - The Port Pirie Cohort Study
dc.typeJournal article
pubs.publication-statusPublished

Files