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Lead is a confirmed neurotoxin, but questions remain about lead-associated intellectual deficits at blood lead levels < 10 microg/dL and whether lower exposures are, for a given change in exposure, associated with greater deficits. The objective of this study was to examine the association of intelligence test scores and blood lead concentration, especially(More)
BACKGROUND Recent evidence suggests that low-level environmental exposure to manganese adversely affects child growth and neurodevelopment. Previous studies have addressed the effects of prenatal exposure, but little is known about developmental effects of early postnatal exposure. METHODS We studied 448 children born in Mexico City from 1997 through(More)
BACKGROUND The impact of prenatal lead exposure on neurodevelopment remains unclear in terms of consistency, the trimester of greatest vulnerability, and the best method for estimating fetal lead exposure. OBJECTIVE We studied prenatal lead exposure's impact on neurodevelopment using repeated measures of fetal dose as reflected by maternal whole blood and(More)
BACKGROUND Evidence suggests that p,p'-dichlorodiphenyldichloroethene (DDE) affects neurodevelopment in infants, although a critical exposure window has not yet been identified. OBJECTIVES Our goal was to assess the prenatal DDE exposure window and its effect on the psychomotor development index (PDI) and mental development index (MDI) during the first(More)
OBJECTIVE A number of prospective studies have examined lead levels in umbilical cord blood at birth as predictors of infant mental development. Although several have found significant inverse associations, others have not. Measurement of lead levels in maternal bone, now recognized as the source of much fetal exposure, has the potential to serve as a(More)
The first step in modeling lead kinetics during pregnancy includes a description of sequential maternal blood lead (PbB) during pregnancy and the factors controlling it. We analyzed PbB of 105 women living in the Valley of Mexico from week 12 to week 36 of pregnancy and again at parturition. We also used data from all women contributing blood at any stage(More)
BACKGROUND The results of previous studies suggest that prenatal exposure to bis[p-chlorophenyl]-1,1,1-trichloroethane (DDT) and to its main metabolite, 2,2-bis(p-chlorophenyl)-1,1-dichloroethylene (DDE), impairs psychomotor development during the first year of life. However, information about the persistence of this association at later ages is limited. (More)
BACKGROUND Most toxicologic studies focus on a single agent, although this does not reflect real-world scenarios in which humans are exposed to multiple chemicals. OBJECTIVES We prospectively studied manganese-lead interactions in early childhood to examine whether manganese-lead coexposure is associated with neurodevelopmental deficiencies that are more(More)
We examined the association of maternal prenatal [range of median blood lead level 7.5-9.0 microg/dl (0.36-0.43 micromol/l) during pregnancy] and child postnatal blood lead level [range of median blood lead level from birth to 48 months 7.0-10.0 microg/dl (0.34-0.48 micromol/l)] with head circumference in from 119 to 199 children from the Mexico City(More)
OBJECTIVE Low-level postnatal lead exposure is associated with poor intellectual development in children, although effects of prenatal exposure are less well studied. We hypothesized that prenatal lead exposure would have a more powerful and lasting impact on child development than postnatal exposure. DESIGN We used generalized linear mixed models with(More)