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Environ Int. 2018 Dec;121(Pt 2):1235-1242. doi: 10.1016/j.envint.2018.10.043. Epub 2018 Nov 2.

Prenatal, concurrent, and sex-specific associations between blood lead concentrations and IQ in preschool Canadian children.

Author information

1
Centre de recherche du Centre Hospitalier Universitaire de Québec, Québec, Canada; École de psychologie, Université Laval, Quebec, Québec, Canada. Electronic address: Mireille.desrochers-couture@crchudequebec.ulaval.ca.
2
Department of Environmental Health, Harvard T. H. Chan School of Public Health, Boston, MA, USA. Electronic address: youlhote@hsph.harvard.edu.
3
Population Studies Division, Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada. Electronic address: Tye.Arbuckle@canada.ca.
4
Department of Obstetrics and Gynecology, Université de Sherbrooke, Centre Hospitalier Universitaire de Sherbrooke, Québec, Canada. Electronic address: william.fraser@umontreal.ca.
5
CHU Sainte-Justine Research Center, Mother and Child University Hospital Center, Montreal, Québec, Canada; Department of Psychiatry, University of Montreal, Montreal, QC, Canada. Electronic address: jean.seguin@umontreal.ca.
6
Centre de recherche du Centre Hospitalier Universitaire de Québec, Québec, Canada. Electronic address: Emmanuel.Ouellet@crchudequebec.ulaval.ca.
7
Centre de recherche du Centre Hospitalier Universitaire de Québec, Québec, Canada; École de psychologie, Université Laval, Quebec, Québec, Canada. Electronic address: Nadine.Forget-Dubois@psy.ulaval.ca.
8
Centre de toxicologie du Québec, Institut national de santé publique du Québec, Québec City, Québec, Canada. Electronic address: pierre.ayotte@inspq.qc.ca.
9
École de psychologie, Université Laval, Quebec, Québec, Canada. Electronic address: Michel.Boivin@psy.ulaval.ca.
10
Faculty of Health Sciences, Simon Fraser University, Vancouver, British Columbia, Canada. Electronic address: bpl3@sfu.ca.
11
Centre de recherche du Centre Hospitalier Universitaire de Québec, Québec, Canada; École de psychologie, Université Laval, Quebec, Québec, Canada. Electronic address: gina.muckle@crchudequebec.ulaval.ca.

Abstract

BACKGROUND:

Lead exposure predicts altered neurodevelopment and lower intelligence quotient (IQ) in children, but few studies have examined this association in children who have relatively low blood lead concentrations.

OBJECTIVES:

To test the associations between blood lead concentrations and cognitive function in Canadian preschoolers, with a possible moderation by sex.

METHODS:

The data were gathered from 609 mother-child pairs from the Maternal-Infant Research on Environmental Chemicals (MIREC) Study. Lead was measured in umbilical and maternal blood, and in children's venous blood at age 3-4 years. Cognitive function was measured with the Wechsler Preschool and Primary Scale of Intelligence (WPPSI-III) at 3-4 years. We tested the relationship between WPPSI-III scores and blood lead concentrations with multiple linear regression, adding child sex as a moderator.

RESULTS:

Median blood lead concentrations for the mother at 1st trimester and 3rd trimester of pregnancy, and for cord and child blood were 0.60 μg/dL, 0.58 μg/dL, 0.79 μg/dL and 0.67 μg/dL, respectively. We found no association between cord blood lead concentrations and WPPSI-III scores in multivariable analyses. However, cord blood lead concentrations showed a negative association with Performance IQ in boys but not in girls (B = 3.44; SE = 1.62; 95% CI: 0.82, 5.98). No associations were found between WPPSI-III scores and prenatal maternal blood or concurrent child blood lead concentrations.

CONCLUSIONS:

Prenatal blood lead concentrations below 5 μg/dL were still associated with a decline in cognitive function in this Canadian cohort, but only for boys.

KEYWORDS:

Blood lead concentrations; Canadian children; Intelligence quotient; Sex differences

PMID:
30392942
DOI:
10.1016/j.envint.2018.10.043
[Indexed for MEDLINE]
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