Article

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: 4.23). 03/2010; 101(1):63-70. DOI: 10.2105/AJPH.2009.168419
Source: PubMed

ABSTRACT 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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    ABSTRACT: Caste, a proxy of socioeconomic position, can influence the neurodevelopment of children through several pathways, including exposure to toxic elements. Studies from developing countries where caste is represented by prevailing caste groups and people are highly exposed to toxic elements can provide useful insights into the mechanisms of neurodevelopmental inequities among children. This study aims to investigate the impact of caste on the neurodevelopment of children from birth to 36 months of age in Chitwan Valley, Nepal, where people are exposed to high levels of arsenic (As) and lead (Pb). Participants (N = 94) were mother-infant pairs from the Chitwan district in Nepal. The neurodevelopment of the infants was assessed using the Brazelton Neonatal Behavioral Assessment Scale, Third Edition, (NBAS III) at birth and the Bayley Scales of Infant Development, Second Edition, (BSID II) at ages 6, 24, and 36 months. Caste was categorized based on surname, which, in Nepal generally refers to one of four caste groups. We also measured the concentrations of As and Pb in cord blood. Caste was positively associated with the state regulation cluster score of the NBAS III at birth after adjustment for covariates (p for trend < 0.01). Adding cord blood As levels attenuated the association (p for trend = 0.12). With regard to neurodevelopment at six months of age, the third-ranked caste group scored higher than the first-ranked caste group on the Mental Development Index (MDI) of the BSID II (coefficient = 3.7; 95% confidence interval (CI) = 1.3 to 6.0). This difference remained significant after adjustment for cord blood As levels and other covariates was made (coefficient = 3.9; 95% CI = 1.2 to 6.7). The remaining clusters of the NBAS III and BSID II at 6, 24, and 36 months were not significantly associated with caste group. Caste was positively associated with the state regulation cluster score of NBAS III at birth. This association was partially mediated by cord blood As levels. However, the negative impact of caste on neurodevelopment disappeared as the children grew. Furthermore, an inverse association between caste and MDI at six months of age was observed. Additional studies are needed to elucidate the mechanism of how caste affects neurodevelopment.
    BMC Pediatrics 02/2014; 14(1):56. DOI:10.1186/1471-2431-14-56 · 1.92 Impact Factor
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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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    ABSTRACT: The US Environmental Protection Agency voluntary phased-out residential use of chlorpyrifos in 2001. In contrast, in Costa Rica, chlorpyrifos-treated bags are increasingly used to protect banana and plantain fruits from insects and to fulfill product standards, even in populated areas. To evaluate children's exposure to chlorpyrifos in villages situated nearby banana plantations and plantain farms in Costa Rica. The study targeted two villages with use of chlorpyrifos-treated bags in nearby banana plantations and plantain farms and one village with mainly organic production. For 140 children from these villages, mostly indigenous Ngäbe and Bribri, parent-interviews and urine samples (n=207) were obtained. Urinary 3,5,6-trichloro-2-pyridinol (TCPy) levels were measured as a biomarker for chlorpyrifos exposure. In the banana and plantain village also environmental contamination to chlorpyrifos was explored. Children from the banana and plantain villages had statistically significant higher urinary TCPy concentrations than children from the referent village; 2.6 and 2.2 versus 1.3μg/g creatinine, respectively. Chlorpyrifos was detected in 30% of the environmental samples as well as in 92% of the hand/foot wash samples. For more than half of the children their estimated intake exceeded the US EPA chronic population adjusted dose. For some, the acute population adjusted dose and the chronic reference dose were also exceeded. Our results suggest that children living nearby plantations with chlorpyrifos-treated bags are exposed to chlorpyrifos levels that may affect their health. Interventions to reduce chlorpyrifos exposure are likely to improve children's health and environment in banana and plantain growing regions.
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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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    International Journal of Health Geographics 06/2012; 11:18. DOI:10.1186/1476-072X-11-18 · 2.62 Impact Factor
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