Chlorpyrifos Exposure and Urban Residential Environment Characteristics as Determinants of Early Childhood Neurodevelopment

Columbia University, New York, NY, USA.
American Journal of Public Health (Impact Factor: 4.55). 03/2010; 101(1):63-70. DOI: 10.2105/AJPH.2009.168419
Source: PubMed


We evaluated whether neighborhood characteristics correlated with early neurodevelopment and whether these characteristics confounded the previously reported association between exposure to chlorpyrifos (an organophosphate insecticide) and neurodevelopment.
We obtained prenatal addresses, chlorpyrifos exposure data, and 36-month Psychomotor Development Index (PDI) and Mental Development Index (MDI) scores for a birth cohort in New York City (born 1998-2002). We used data from the 2000 US Census to estimate measures of physical infrastructure, socioeconomic status, crowding, demographic composition, and linguistic isolation for 1-kilometer network areas around each child's prenatal address. Generalized estimating equations were adjusted for demographics, maternal education and IQ, prenatal exposure to tobacco smoke, caretaking environment quality, and building dilapidation.
Of 266 children included as participants, 47% were male, 59% were Dominican, and 41% were African American. For each standard deviation higher in neighborhood percent poverty, the PDI score was 2.6 points lower (95% confidence interval [CI] = -3.7, -1.5), and the MDI score was 1.7 points lower (95% CI = -2.6, -0.8). Neighborhood-level confounding of the chlorpyrifos-neurodevelopment association was not apparent.
Neighborhood context and chlorpyrifos exposure were independently associated with neurodevelopment, thus providing distinct opportunities for health promotion.

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    • "Similar to earlier studies [3-5,7,8,37-39], newborns in lower caste groups showed less optimal neurodevelopment at birth. This trend was partially mediated by cord blood As levels, suggesting that in utero exposure to As could drive the occurrence of lower-state regulation scores among lower-caste groups. "
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    • "Recent studies suggest there are other neurotoxicological mechanisms in addition to cholinesterase inhibition at lower doses (Eaton et al., 2008; Nomura et al., 2006; Schuh et al., 2002; Rush et al., 2010; Slotkin et al., 2010; Seidler and Slotkin, 2011). In addition, three US children's cohort studies have reported neurodevelopmental deficits, including decreased full-scale IQ and working memory up to the age of 7 years in relation to prenatal exposures to organophosphates in general (Eskenazi et al., 2007; Engel et al., 2007; Rosas and Eskenazi, 2008; Bouchard et al., 2011) and chlorpyrifos in particular (Berkowitz et al., 2004; Rauh et al., 2006; Lovasi et al., 2011; Rauh et al., 2011). Chlorpyrifos is metabolized to the specific metabolite 3,5,6- trichloro-2-pyridinol (TCPy), which after oral exposure is mainly (70%) excreted in the urine, with a half-life in adults of 27 h (Nolan et al., 1984). "
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    • "In addition, other geo-spatial data-sets are often available at the municipal or county level, providing each NCS site with unique spatial data and opportunities to perform neighborhood context analyses. Geo-spatial data sets developed by NYC agencies have been extremely useful in studies of adult health in NYC [49-53] and provide unique opportunities for studying the effects of neighborhood built and social environments on child health and development [49,54]. "
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