Environmental exposure to lead and children's intelligence at the age of seven years. The Port Pirie Cohort Study

Journal Article · Thu Oct 29 00:00:00 EST 1992 · New England Journal of Medicine; (United States)

DOI:https://doi.org/10.1056/NEJM199210293271805· OSTI ID:6968094

Baghurst, P A; McMichael, A J; Wigg, N R; Vimpani, G V; Robertson, E F; Roberts, R J; Tong, S L ^[1]

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1. CSIRO Division of Human Nutrition, Adelaide (Australia)

Exposure to lead in early childhood is thought to result in delayed neuropsychological development. As yet there is little longitudinal evidence to establish whether these effects persist into later childhood. The authors measured IQ scores in 494 seven-year-old children from the lead-smelting community of Port Pirie, Australia, in whom developmental deficits associated with elevated blood lead concentrations had already been reported at the ages of two and four years. Exposure to lead was estimated from the lead concentrations in maternal blood samples drawn antenatally and at delivery and from blood samples drawn from the children at birth (umbilical-cord blood), at the ages of 6 and 15 months and 2 years, and annually thereafter. Data relating to known covariates of child development were collected systematically for each child throughout the first seven years of life. The authors found inverse relations between IQ at the age of seven years and both antenatal and postnatal blood lead concentrations. After adjustment by multiple regression for sex, parents' level of education, maternal age at delivery, parents' smoking status, socioeconomic status, quality of the home environment, maternal IQ, birth weight, birth order, feeding method (breast, bottle, or both), duration of breast-feeding, and whether the child's natural parents were living together, the relation with lead exposure was still evident for postnatal blood samples, particularly within the age range of 15 months to 4 years. For an increase in blood lead concentration from 10 micrograms per deciliter (0.48 mumol per liter) to 30 micrograms per deciliter (1.45 mumol per liter), expressed as the average of the concentrations at 15 months and 2, 3, and 4 years, the estimated reduction in the IQ of the children was in the range of 4.4 points (95 percent confidence interval, 2.2 to 6.6) to 5.3 points (95 percent confidence interval, 2.8 to 7.8).

• OSTI ID: 6968094
• Journal Information: New England Journal of Medicine; (United States), Vol. 327:18; ISSN 0028-4793
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BRAIN
SENSITIVITY
LEAD
TOXICITY
AUSTRALIA
CHILDREN
ENVIRONMENTAL EXPOSURE
MULTIVARIATE ANALYSIS
AGE GROUPS
AUSTRALASIA
BODY
CENTRAL NERVOUS SYSTEM
DEVELOPED COUNTRIES
ELEMENTS
MATHEMATICS
METALS
NERVOUS SYSTEM
ORGANS
STATISTICS
560300* - Chemicals Metabolism & Toxicology