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Neurotoxicology. 2019 Sep 9;75:105-115. doi: 10.1016/j.neuro.2019.09.006. [Epub ahead of print]

Prenatal lead exposure and childhood executive function and behavioral difficulties in project viva.

Author information

1
Department of Environmental Health, Boston University, Boston, MA, USA. Electronic address: vfru1212@bu.edu.
2
Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, MA, USA.
3
Department of Environmental Medicine and Public Health, Icahn School of Medicine, Mount Sinai, New York, NY, USA.
4
Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, Berkeley, CA, USA.
5
Department of Neurology, Boston Children's Hospital, Boston, MA, USA; Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
6
Department of Epidemiology, Boston University, Boston, MA, USA.
7
Department of Environmental Health, Boston University, Boston, MA, USA; Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Department of Neurology, Boston University School of Medicine, Boston, MA, USA.
8
Department of Environmental Health, Boston University, Boston, MA, USA.

Abstract

BACKGROUND:

Lead is an established neurotoxicant and early life exposure to lead is associated with detrimental impacts on IQ and several neurobehavioral domains. Less is known, however, about effects of prenatal lead exposure below 5 μg/dL on executive function and on social, emotional and self-regulatory behaviors in childhood.

OBJECTIVES:

To examine the association between prenatal lead exposure and childhood executive function and social, emotional and self-regulatory behaviors.

METHODS:

We included 1006 mother-child pairs from the Project Viva prospective pre-birth cohort. We measured prenatal maternal lead in second-trimester erythrocytes. In mid-childhood (median 7.7 years), parents and teachers rated executive function related behaviors using the Behavior Rating Inventory of Executive Function (BRIEF) and behavioral difficulties using the Strengths and Difficulties Questionnaire (SDQ). We used multivariable linear regression models adjusted for maternal, paternal, and child characteristics and metal co-exposures.

RESULTS:

Mean maternal erythrocyte lead concentration was 1.2 μg/dL (interquartile range [IQR] 0.8-1.5 μg /dL), equivalent to approximately 0.4 μg/dL in whole blood. In adjusted models, associations with parent and teacher-rated scales were largely null, although effect estimates were consistently positive, suggesting worse scores with increasing lead levels. For an IQR increase in lead, BRIEF Global Executive Composite (GEC) was 0.73 (95% CI: -0.06, 1.52) points higher for parent-rated scores and 0.42 (95% CI: -0.39, 1.23) points higher for teacher-rated scores. Associations were strongest for parent-rated BRIEF plan/organize (β = 0.85; 95% CI: 0.12, 1.59) and shift (β = 0.88; 95% CI: 0.01, 1.75) subscales, as well as the SDQ emotional problems subscale (β = 0.18; 95% CI: 0.03, 0.33).

DISCUSSION:

In this cohort with lead levels commonly experienced by U.S. women, there were few statistically significant associations with childhood executive function and behavior. However, there was a trend of worse neurobehavioral scores with increasing prenatal lead concentrations, in particular for childhood emotional problems and capacity to plan/organize and shift. Our results highlight the importance of continuing efforts to eliminate lead exposure in the general population.

KEYWORDS:

Childhood; Environmental epidemiology; Lead; Neurobehavior; Prenatal exposure

PMID:
31513824
DOI:
10.1016/j.neuro.2019.09.006
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