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Neurocognitive impairment in lead-exposed children of Andean lead-glazing workers.
J Occup Environ Med. 2005 Mar; 47(3):306-12.JO

Abstract

OBJECTIVE

The level of lead (Pb) exposure necessary to induce intellectual impairment has not been firmly established. Some studies using conventional language-based intelligence tests have reported that pediatric blood lead (PbB) levels lower than 10 microg/dL (0.483 micromol/L) are associated with neurocognitive impairment. However, these tests may introduce cultural biases in the assessment of intellectual functioning. The objective of this study was to assess the effects of PbB concentration on nonverbal intelligence in Andean children with chronic environmental Pb exposure using a nonlanguage-based test of cognitive functioning.

METHODS

Using Raven Colored Progressive Matrices (RCPM) as a measure of nonverbal intelligence, this study investigated the effects of Pb exposure (biomarker: PbB levels) on intellectual functioning in 188 chronically Pb-exposed children (age range: 5.33-11.67 years) of Ecuadorian Andean Pb-glazing workers.

RESULTS

The mean PbB level of the 188 children was 29.3 microg/dL (range: 3.5-94.3 microg/dL). Forty-seven children had PbB levels <10 microg/dL (Centers for Disease Control and Prevention [CDC] I classification), of which 30 had abnormal (ie, < or =25th percentile) RCPM standard scores. Of the 141 children with PbB levels > or =10 microg/dL, 97 had abnormal RCPM scores. A regression analysis revealed a statistically significant negative association (r = -0.331, P < 0.0001) between PbB level and RCPM standard score. Conversion of RCPM standard scores to estimated IQ scores showed an approximate two-point decrease in IQ for each 10-microg/dL increment in PbB level from 10 to >70 microg/dL.

CONCLUSIONS

Performance on a test of nonverbal intelligence was inversely associated with chronic Pb exposure in Andean children with PbB levels below and above the CDC risk management level of 10 microg/dL, with the decline in test scores suggesting a dose-response relationship.

Authors+Show Affiliations

Department of Neurology, Harvard Medical School/The Biological Laboratories, 16 Divinity Avenue, Cambridge, MA 02138, USA. allen_counter@harvard.eduNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15761328

Citation

Counter, S Allen, et al. "Neurocognitive Impairment in Lead-exposed Children of Andean Lead-glazing Workers." Journal of Occupational and Environmental Medicine, vol. 47, no. 3, 2005, pp. 306-12.
Counter SA, Buchanan LH, Ortega F. Neurocognitive impairment in lead-exposed children of Andean lead-glazing workers. J Occup Environ Med. 2005;47(3):306-12.
Counter, S. A., Buchanan, L. H., & Ortega, F. (2005). Neurocognitive impairment in lead-exposed children of Andean lead-glazing workers. Journal of Occupational and Environmental Medicine, 47(3), 306-12.
Counter SA, Buchanan LH, Ortega F. Neurocognitive Impairment in Lead-exposed Children of Andean Lead-glazing Workers. J Occup Environ Med. 2005;47(3):306-12. PubMed PMID: 15761328.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Neurocognitive impairment in lead-exposed children of Andean lead-glazing workers. AU - Counter,S Allen, AU - Buchanan,Leo H, AU - Ortega,Fernando, PY - 2005/3/12/pubmed PY - 2005/6/9/medline PY - 2005/3/12/entrez SP - 306 EP - 12 JF - Journal of occupational and environmental medicine JO - J Occup Environ Med VL - 47 IS - 3 N2 - OBJECTIVE: The level of lead (Pb) exposure necessary to induce intellectual impairment has not been firmly established. Some studies using conventional language-based intelligence tests have reported that pediatric blood lead (PbB) levels lower than 10 microg/dL (0.483 micromol/L) are associated with neurocognitive impairment. However, these tests may introduce cultural biases in the assessment of intellectual functioning. The objective of this study was to assess the effects of PbB concentration on nonverbal intelligence in Andean children with chronic environmental Pb exposure using a nonlanguage-based test of cognitive functioning. METHODS: Using Raven Colored Progressive Matrices (RCPM) as a measure of nonverbal intelligence, this study investigated the effects of Pb exposure (biomarker: PbB levels) on intellectual functioning in 188 chronically Pb-exposed children (age range: 5.33-11.67 years) of Ecuadorian Andean Pb-glazing workers. RESULTS: The mean PbB level of the 188 children was 29.3 microg/dL (range: 3.5-94.3 microg/dL). Forty-seven children had PbB levels <10 microg/dL (Centers for Disease Control and Prevention [CDC] I classification), of which 30 had abnormal (ie, < or =25th percentile) RCPM standard scores. Of the 141 children with PbB levels > or =10 microg/dL, 97 had abnormal RCPM scores. A regression analysis revealed a statistically significant negative association (r = -0.331, P < 0.0001) between PbB level and RCPM standard score. Conversion of RCPM standard scores to estimated IQ scores showed an approximate two-point decrease in IQ for each 10-microg/dL increment in PbB level from 10 to >70 microg/dL. CONCLUSIONS: Performance on a test of nonverbal intelligence was inversely associated with chronic Pb exposure in Andean children with PbB levels below and above the CDC risk management level of 10 microg/dL, with the decline in test scores suggesting a dose-response relationship. SN - 1076-2752 UR - https://www.unboundmedicine.com/medline/citation/15761328/Neurocognitive_impairment_in_lead_exposed_children_of_Andean_lead_glazing_workers_ L2 - https://doi.org/10.1097/01.jom.0000155717.45594.65 DB - PRIME DP - Unbound Medicine ER -