Prenatal Airborne Polycyclic Aromatic Hydrocarbon Exposure and Child IQ at Age 5 Years

Department of Environmental Health Sciences, Columbia Center for Children's Environmental Healt, Mailman School of Public Health, Columbia University, New York, New York 10032, USA.
PEDIATRICS (Impact Factor: 5.47). 09/2009; 124(2):e195-202. DOI: 10.1542/peds.2008-3506
Source: PubMed


This study evaluated the relationship between prenatal exposure to airborne polycyclic aromatic hydrocarbons (PAHs) and child intelligence.
Children of nonsmoking black or Dominican-American women residing in New York City were monitored from in utero to 5 years of age, with determination of prenatal PAH exposure through personal air monitoring for the mothers during pregnancy. At 5 years of age, intelligence was assessed for 249 children by using the Wechsler Preschool and Primary Scale of Intelligence-Revised. Multivariate linear regression models were used to estimate and to test the associations between prenatal PAH exposure and IQ.
After adjustment for maternal intelligence, quality of the home caretaking environment, environmental tobacco smoke exposure, and other potentially confounding factors, high PAH levels (above the median of 2.26 ng/m(3)) were inversely associated with full-scale IQ (P = .007) and verbal IQ (P = .003) scores. Children in the high-exposure group had full-scale and verbal IQ scores that were 4.31 and 4.67 points lower, respectively, than those of less-exposed children (<or=2.26 ng/m(3)). The associations between logarithmically transformed, continuous, PAH levels and these IQ measures also were significant (full-scale IQ: beta = -3.00; P = .009; verbal IQ: beta = -3.53; P = .002).
These results provide evidence that environmental PAHs at levels encountered in New York City air can affect children's IQ adversely.

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Available from: Lori Hoepner, Sep 24, 2014
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    • "PAHs are also linked to lower I.Q. (Perera et al., 2009), anxiety, and depression in children (Perera et al., 2012b). Traffic pollution is also associated with an increased risk of otitis media, or inner ear infections (Brauer et al., 2006). "
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    • "A number of prior reports in other populations have indicated adverse neurodevelopmental effects of air pollution (Edwards et al., 2010; Perera et al., 2009; Sram et al., 1996; Tang et al., 2014). In the present NYC cohort, prenatal exposure to PAH, as measured by 48-hour prenatal air monitoring , was associated with delayed mental development at age 3 years (Perera et al., 2006) and was associated with lower intelligence at age 5 years in both the NYC cohort and in a parallel Polish cohort (Edwards et al., 2010; Perera et al., 2009). In those reports, the association with PAH–DNA adducts was not examined. "
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    ABSTRACT: Polycyclic aromatic hydrocarbons are common carcinogenic and neurotoxic urban air pollutants. Toxic exposures, including air pollution, are disproportionately high in communities of color and frequently co-occur with chronic economic deprivation. We examined whether the association between child IQ and prenatal exposure to polycyclic aromatic hydrocarbons differed between groups of children whose mothers reported high vs. low material hardship during their pregnancy and through child age 5. We tested statistical interactions between hardships and polycyclic aromatic hydrocarbons, as measured by DNA adducts in cord blood, to determine whether material hardship exacerbated the association between adducts and IQ scores. Prospective cohort. Participants were recruited from 1998 to 2006 and followed from gestation through age 7 years. Urban community (New York City) PARTICIPANTS: A community-based sample of 276 minority urban youth EXPOSURE MEASURE: Polycyclic aromatic hydrocarbon-DNA adducts in cord blood as an individual biomarker of prenatal polycyclic aromatic hydrocarbon exposure. Maternal material hardship self-reported prenatally and at multiple timepoints through early childhood. Child IQ at 7 years assessed using the Wechsler Intelligence Scale for Children. Significant inverse effects of high cord PAH-DNA adducts on full scale IQ, perceptual reasoning and working memory scores were observed in the groups whose mothers reported a high level of material hardship during pregnancy or recurring high hardship into the child's early years, and not in those without reported high hardship. Significant interactions were observed between high cord adducts and prenatal hardship on working memory scores (β=-8.07, 95% CI (-14.48, -1.66) and between high cord adducts and recurrent material hardship (β=-9.82, 95% CI (-16.22, -3.42). The findings add to other evidence that socioeconomic disadvantage can increase the adverse effects of toxic physical "stressors" like air pollutants. Observed associations between high cord adducts and reduced IQ were significant only among the group of children whose mothers reported high material hardship. These results indicate the need for a multifaceted approach to prevention. Copyright © 2015. Published by Elsevier Inc.
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    • "Two of the cognitive outcomes related to prenatal major roadway proximity in our study (verbal and non-verbal intelligence) were inversely associated with exposure to PAHs measured in late pregnancy among 5-year-olds in New York City and Poland (Edwards et al. 2010; Perera et al. 2009). While we know of no previous reports of associations of early-life residential roadway proximity with cognitive outcomes in children, prenatal proximity to freeways was associated in another study with development of autism in childhood (Volk et al. 2011). "
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    ABSTRACT: Influences of prenatal and early life exposures to air pollution on cognition are not well-understood. Examine associations of gestational and childhood exposure to traffic-related pollution with childhood cognition. We studied 1,109 mother-child pairs in Project Viva, a prospective birth cohort study in Eastern Massachusetts (USA). In mid-childhood (mean age 8.0 years), we measured verbal and non-verbal intelligence, visual motor abilities, and visual memory. For periods in late pregnancy and childhood we estimated spatially and temporally resolved black carbon (BC) and fine particulate matter (PM2.5) exposures, residential proximity to major roadways, and near-residence traffic density. We used linear regression models to examine associations of exposures with cognitive assessment scores, adjusted for potential confounders. Compared to children living ≥200 m from a major roadway at birth, those living <50 m away had lower non-verbal IQ (-7.5 points; 95% confidence interval (CI): -13.1, -1.9), and somewhat lower verbal IQ (-3.8 points; 95% CI: -8.2, 0.6) and visual motor abilities (-5.3 points; 95% CI: -11.0, 0.4). Cross-sectional associations of major roadway proximity and cognition at mid-childhood were weaker. Prenatal and childhood exposure to traffic density and PM2.5 did not appear associated with poorer cognitive performance. Third trimester and childhood BC exposures were associated with lower verbal IQ in minimally adjusted models, but after adjustment for socioeconomic covariates, associations were attenuated or reversed. Residential proximity to major roadways during gestation and early-life may affect cognitive development. Influences of pollutants and socioeconomic conditions on cognition may be difficult to disentangle.
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