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Environ Int. 2017 Jan;98:191-197. doi: 10.1016/j.envint.2016.11.005. Epub 2016 Nov 16.

Maternal stress modifies the effect of exposure to lead during pregnancy and 24-month old children's neurodevelopment.

Author information

1
National Council of Science and Technology, Avenida Insurgentes Sur 1582, Benito Juárez, Crédito Constructor, 03940 Ciudad de México, D.F., México. Electronic address: mtamayo@hsph.harvard.edu.
2
National Institute of Public Health, Universidad No. 655 Colonia Santa María, Ahuacatitlán, Cerrada Los Pinos y Caminera, C.P. 62100, Cuernavaca, Morelos, México. Electronic address: mmtellez@insp.mx.
3
National Institute of Public Health, Universidad No. 655 Colonia Santa María, Ahuacatitlán, Cerrada Los Pinos y Caminera, C.P. 62100, Cuernavaca, Morelos, México. Electronic address: bvaldivia@insp.mx.
4
National Institute of Perinatology, Calle Montes Urales #800, Miguel Hidalgo, Lomas Virreyes, 11000 Ciudad de México, D.F., México. Electronic address: lschnaas@hotmail.com.
5
National Institute of Perinatology, Calle Montes Urales #800, Miguel Hidalgo, Lomas Virreyes, 11000 Ciudad de México, D.F., México. Electronic address: erikaosorio4@hotmail.com.
6
Department of Biostatistics, Harvard T.H. Chan School of Public Health, 677 Huntington Ave, Boston, MA 02115, United States. Electronic address: bcoull@hsph.harvard.edu.
7
Department Environmental Health, Harvard T.H. Chan School of Public Health, 677 Huntington Ave, Boston, MA 02115, United States. Electronic address: david.bellinger@childrens.harvard.edu.
8
Department of Pediatrics, Icahn School of Medicine at Mount Sinai, 1428 Madison Ave, New York, NY 10029, United States. Electronic address: rosalind.wright@mssm.edu.
9
Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, 1428 Madison Ave, New York, NY 10029, United States. Electronic address: robert.wright@mssm.edu.

Abstract

BACKGROUND:

Lead and psychosocial stress disrupt similar but not completely overlapping mechanisms. Exposure during the prenatal period to each of these insults singularly has been found to alter normal neurodevelopment; however, longitudinal associations with stress modifying the effect of lead have not been sufficiently analyzed in epidemiologic studies.

OBJECTIVE:

To evaluate prenatal stress as an effect modifier of gestational lead neurotoxicity.

METHODS:

We used a structural equations modeling approach with a trivariate response to evaluate cognitive, language and motor scores of the Bayley Scales of Infant Development-III in 24month-old children (n=360). Maternal blood lead levels were measured at the 2nd and 3rd trimester and psychosocial stress during pregnancy was assessed using a negative life events (NLE) scale derived from the CRYSIS questionnaire.

RESULTS:

3rd trimester lead (mean 3.9±3.0 SDμg/dL) and stress (median=3 NLE) were negatively associated with Bayley III scores. Using the model's results we generated profiles for 0, 2, 4 and 6 NLE across lead levels (up to 10μg/dL) and observed a dose-response for the developmental scores when lead levels were below 2μg/dL. Each NLE curve had a different shape across increasing lead levels. Higher stress (NLE=6) resulted in lower cognitive scores for both sexes, in lower language scores in girls but not boys. In the absence of stress we saw a negative association with lead for all scores, however for language and motor scores, higher stress seemed to mask this association.

CONCLUSIONS:

Our work examined and confirmed prenatal stress exposure as a modifier of the well-known neurotoxic effects of prenatal lead. It adds to the existing evidence pointing at the importance of studying the co-exposure of chemical and non-chemical exposures, specifically of considering the emotional environment of children at early developmental stages of life.

KEYWORDS:

Effect modification; Lead; Neurodevelopment; Prenatal; Stress

PMID:
27865525
PMCID:
PMC5221478
DOI:
10.1016/j.envint.2016.11.005
[Indexed for MEDLINE]
Free PMC Article

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