This study is among the first to examine specific neurobehavioral deficits in children exposed at very low lead levels. A systematic analysis for the presence of a threshold of lead exposure was ...conducted. The sample consisted of 246 African American, inner-city children from whom blood lead concentrations were assessed at 7.5 years of age. The results consistently show neurobehavioral deficits in relation to low levels of lead in the areas of intelligence, reaction time, visual–motor integration, fine motor skills, attention, including executive function, off-task behaviors, and teacher-reported withdrawn behaviors. Effects were identified in the specific domains of attention, executive function, visual–motor integration, social behavior, and motor skills, which have been previously suggested as part of lead's “behavioral signature”. Visual inspection of nonparametric regression plots suggested a gradual linear dose–response relation for most endpoints. No threshold discontinuity was evident. Regression analyses in which lead exposure was dichotomized at 10 μg/dl were no more likely to be significant than analyses dichotomizing exposure at 5 μg/dl. Given that associations were found between lead levels as low as 3 μg/dl for multiple outcomes, these data provide additional evidence that there is no apparent lower bound threshold for postnatal lead exposure.
Background
Animal studies have demonstrated adverse effects of prenatal alcohol exposure on placental development, but few studies have examined these effects in humans. Little is known about effects ...of prenatal exposure to methamphetamine, marijuana, and cigarette smoking on placental development.
Methods
Placentas were collected from 103 Cape Coloured (mixed ancestry) pregnant women recruited at their first antenatal clinic visit in Cape Town, South Africa. Sixty‐six heavy drinkers and 37 nondrinkers were interviewed about their alcohol, cigarette smoking, and drug use at 3 antenatal visits. A senior pathologist, blinded to exposure status, performed comprehensive pathology examinations on each placenta using a standardized protocol. In multivariable regression models, effects of prenatal exposure were examined on placental size, structure, and presence of infections and meconium.
Results
Drinkers reported a binge pattern of heavy drinking, averaging 8.0 drinks/occasion across pregnancy on 1.4 d/wk. 79.6% smoked cigarettes; 22.3% used marijuana; and 17.5% used methamphetamine. Alcohol exposure was related to decreased placental weight and a smaller placenta‐to‐birthweight ratio. By contrast, methamphetamine was associated with larger placental weight and a larger placenta‐to‐birthweight ratio. Marijuana was also associated with larger placental weight. Alcohol exposure was associated with increased risk of placental hemorrhage. Prenatal alcohol, drug, and cigarette use were not associated with chorioamnionitis, villitis, deciduitis, or maternal vascular underperfusion. Alcohol and cigarette smoking were associated with a decreased risk of intrauterine passing of meconium, a sign of acute fetal stress and/or hypoxia; methamphetamine, with an increased risk.
Conclusions
This is the first human study to show that alcohol, methamphetamine, and marijuana were associated with distinct patterns of pathology, suggesting different mechanisms mediating their effects on placental development. Given the growing body of evidence linking placental abnormalities to neurodevelopmental deficits, these findings may be important in the long‐term teratogenic effects of prenatal alcohol and drug exposure.
In a prenatally recruited, prospective longitudinal cohort, alcohol exposure was related to decreased placental weight and a smaller placenta‐to‐birthweight ratio. By contrast, methamphetamine was associated with larger placental weight and a larger placenta‐to‐birthweight ratio; marijuana with larger placental weight. This is the first study to demonstrate distinct alcohol‐, methamphetamine‐, and marijuana‐related patterns of placental pathology. Given evidence linking placental abnormalities to neurodevelopmental deficits, these findings may be important in the teratogenic effects of prenatal alcohol and drug exposure.
Prenatal alcohol exposure (PAE) impacts the neurodevelopment of the fetus, including the infant's ability to self-regulate. Heart rate variability (HRV), that is, the beat-to-beat variability in ...heart rate, is a non-invasive measurement that can indicate autonomic nervous system (ANS) function/dysfunction.
The study consisted of a subset of our ENRICH-2 cohort: 80 participants (32 PAE and 48 Controls) who had completed three visits during pregnancy. The participants completed a comprehensive assessment of PAE and other substances throughout pregnancy and assessments for stress, anxiety, and depression in the third trimester. At 24 h of age, infant HRV was assessed in the hospital during the clinically indicated heel lance; 3- to 5-min HRV epochs were obtained during baseline, heel lancing, and recovery episodes.
Parameters of HRV differed in infants with PAE compared to Controls during the recovery phase of the heel lance (respiratory sinus arrhythmia (RSA) and high-frequency (HF), p < 0.05). Increased maternal stress was also strongly associated with abnormalities in RSA, HF, and low-frequency / high-frequency (LF/HF, p's < 0.05).
Alterations in ANS regulation associated with PAE and maternal stress may reflect abnormal development of the hypothalamic-pituitary-adrenal axis and have long term implications for infant responsiveness and self-regulation.
Previous studies have focused on effects of moderate to heavy prenatal alcohol exposure (PAE) on autonomic dysregulation, but little is known about the effects of lower levels of PAE on infant self-regulation and heart rate variability (HRV). Prenatal stress is another risk factor for autonomic dysregulation. Mild PAE impacts infant self-regulation, which can be assessed using HRV. However, the effect of prenatal stress is stronger than that of mild PAE or other mental health variables on autonomic dysregulation.
Given that their traditional lifestyle and diet still relies on fish and other marine species for sustenance, the Inuit are highly exposed to polychlorinated biphenyls (PCBs) and PCBs are ...increasingly linked to obesity. However, evidence is not consistent regarding which periods of exposure are most relevant. In this study, we examine whether in utero, childhood, and adolescent exposure to PCBs are related to physical growth at adolescence.
Inuit adolescents from Canada (N=212) enrolled in a prospective longitudinal cohort study since birth were assessed for height, weight, body mass index (BMI), fat mass index (FMI) and fat free mass index (FFMI) at 18 years of age. PCB 153 concentrations were quantified in blood samples obtained at birth (umbilical cord), 11, and 18 years of age. Maternal anthropometrics were measured and those for the newborns collected from medical records. Data on biological mothers and participants’ sociodemographic characteristics and food security were collected using interviews. Multiple linear regression analyses were used to test associations between PCB 153 concentrations and adolescent anthropometric measures.
Cord PCB 153 was not related to height or FFMI at adolescence. By contrast, analyses showed that cord PCB 153 was related to higher BMI, FMI and marginally to weight in girls but not boys. Child PCB 153 was not related to height, weight or FFMI in adolescence. Child PCB 153 was related to lower BMI and FMI at adolescence in both sexes, particularly among those considered overweight or obese during childhood. Adolescent PCB 153 was not associated with any outcome.
This study suggests that prenatal exposure to PCBs may have a long-term effect on growth in early adulthood among girls and identifies the peri-pubertal period as another window of sensitivity for the action of PCBs. Our findings also suggest that exposure to PCBs and body size be documented in multiple time periods from infancy to adulthood.
•Prenatal exposure to PCBs may have a long-term effect on growth among girls.•Peri-pubertal period identified as a window of sensitivity for PCBs.•Exposure to PCBs and body size be documented in multiple time periods.
Background: Alcohol consumption during pregnancy, a known teratogen often associated with drug use and smoking is a well‐known public health concern.
Aim: This study provides prevalence data for ...alcohol, smoking, and illicit drug use before, during, and after pregnancy among Inuit. Factors associated with alcohol use are also identified.
Methods: Two hundred and eight Inuit women from Arctic Quebec were interviewed at mid‐pregnancy, and at 1 and 11 months postpartum to provide descriptive data on smoking, alcohol, and drug use during pregnancy, and the year before and after pregnancy. Sociodemographic and family characteristics potentially associated with alcohol use were documented.
Results: Ninety‐two percent of the women reported smoking and 61% reported drinking during pregnancy. Episodes of binging during pregnancy were reported by 62% of the alcohol users, which correspond to 38% of pregnant women. Thirty‐six percent of the participants reported using marijuana during pregnancy. Alcohol use and binge drinking during pregnancy were more likely to be reported by women who lived in less crowded houses, had a better knowledge of a second language, drank alcohol more often and in larger amounts prior to pregnancy, and used illicit drugs. Binge drinkers were more likely to be single women and to have had fewer previous pregnancies. Postpartum distress and violence were more likely to be experienced by women who used alcohol during pregnancy. Binge drinking during pregnancy was best predicted by drinking habits before pregnancy, maternal symptoms of depression, the use of illicit drugs during pregnancy, and the number of young children living with the mother.
Conclusions: These results confirm that alcohol is a major risk factor to maternal and child health in this population, underscoring the need for culturally relevant and effective prevention programs.
Background: Lead (Pb) and polychlorinated biphenyls (PCBs) are neurotoxic contaminants that have been related to impairment in response inhibition. Objectives: In this study we examined the ...neurophysiological correlates of the response inhibition deficits associated with these exposures, using event-related potentials (ERPs) in a sample of schoolage Inuit children from Arctic Québec exposed through their traditional diet. Methods: In a prospective longitudinal study, we assessed 196 children (mean age, 11.3 years) on a visual go/no-go response inhibition paradigm. Pb, PCB, and mercury (Hg) concentrations were analyzed in cord and current blood samples. Hierarchical multiple regression analyses were conducted to examine the associations of contaminant levels to go/no-go performance (mean reaction time, percent correct go, percent correct no-go) and five ERPs N2, P3, error-related negativity, error positivity (Pe), and correct response positivity (Pc) after control for confounding variables. Results: Current blood Pb concentrations were associated with higher rates of false alarms and with decreased P3 amplitudes to go and no-go trials. Current plasma PCB-153 concentrations were associated with slower reaction times and with reduced amplitudes of the Pe and Pc responserelated potentials. Hg concentrations were not related to any outcome on this task but showed significant interactions with other contaminants on certain outcomes. Conclusions: These results suggest that Pb exposure during childhood impairs the child's ability to allocate the cognitive resources needed to correctly inhibit a prepotent response, resulting in increased impulsivity. By contrast, postnatal PCB exposure appears to affect processes associated with error monitoring, an aspect of behavioral regulation required to adequately adapt to the changing demands of the environment, which results in reduced task efficiency.
Background
Rodent studies have consistently shown that prenatal alcohol exposure (PAE) impairs performance on the Morris water maze (MWM), a test of spatial navigation. A previous study comparing ...boys with fetal alcohol syndrome (FAS) to controls found poorer performance on the virtual water maze (VWM), a human analogue of the MWM. We examined PAE effects on virtual navigation in both sexes using the VWM in a moderately exposed Detroit cohort (N = 104; mean = 19.4 year) and a heavily exposed Cape Town, South African cohort (N = 62; mean = 10.4 year).
Methods
The task requires the participant to learn the location of a hidden platform in a virtual pool of water. The set of acquisition trials requires the participant to learn the location of the hidden platform and to return to that location repeatedly. The single‐probe trial requires the participant to return to that location without knowing that the platform has been removed.
Results
No effects of FASD diagnostic group or PAE were detected on virtual navigation in the Detroit moderately exposed cohort. By contrast, in the more heavily exposed Cape Town cohort, the FAS/partial FAS (PFAS) group took longer to locate the hidden platform during acquisition than nonsyndromal heavily exposed (HE) and control groups, an effect that persisted even after controlling for IQ. Among boys, both the FAS/PFAS and HE groups performed more poorly than controls during acquisition, and both boys and girls born to women who binge drank performed more poorly than those born to abstainers/light drinkers. Both amount and frequency of PAE were related to poorer performance during the probe trial at 10 years of age.
Conclusions
These data demonstrate deficits in spatial navigation among heavily exposed syndromal boys and girls and in nonsyndromal exposed boys.
Rodent studies have consistently shown that prenatal alcohol exposure (PAE) impairs performance on the Morris Water Maze (MWM), a test of spatial navigation. Using a human analogue of the MWM, we found that children with heavy prenatal alcohol exposure exhibit deficits in spatial navigation.
Background
Magnetic resonance imaging (MRI) studies have consistently demonstrated disproportionately smaller corpus callosa in individuals with a history of prenatal alcohol exposure (PAE) but have ...not previously examined the feasibility of detecting this effect in infants. Tissue segmentation of the newborn brain is challenging because analysis techniques developed for the adult brain are not directly transferable, and segmentation for cerebral morphometry is difficult in neonates, due to the latter's incomplete myelination. This study is the first to use volumetric structural MRI to investigate PAE effects in newborns using manual tracing and to examine the cross‐sectional area of the corpus callosum (CC).
Methods
Forty‐three nonsedated infants born to 32 Cape Coloured heavy drinkers and 11 controls recruited prospectively during pregnancy were scanned using a custom‐designed birdcage coil for infants, which increases signal‐to‐noise ratio almost 2‐fold compared to the standard head coil. Alcohol use was ascertained prospectively during pregnancy, and fetal alcohol spectrum disorders diagnosis was conducted by expert dysmorphologists. Data were acquired using a multi‐echo FLASH protocol adapted for newborns, and a knowledge‐based procedure was used to hand‐segment the neonatal brains.
Results
CC was disproportionately smaller in alcohol‐exposed neonates than controls after controlling for intracranial volume. By contrast, CC area was unrelated to infant sex, gestational age, age at scan, or maternal smoking, marijuana, or methamphetamine use during pregnancy.
Conclusions
Given that midline craniofacial anomalies have been recognized as a hallmark of fetal alcohol syndrome in humans and animal models since this syndrome was first identified, the CC deficit identified here in newborns may support early identification of a range of midline structural impairments. Smaller CC during the newborn period may provide an early indicator of fetal alcohol‐related cognitive deficits that have been linked to this critically important brain structure in childhood and adolescence.
We used manually traced MRI images to investigate prenatal alcohol exposure effects on corpus callosum (CC) size in 43 nonsedated newborns. CC was disproportionately smaller in alcohol‐exposed neonates than controls after adjustment for intracranial volume. By contrast, CC area was unrelated to sex, gestational age, age at scan, smoking, marijuana, or methamphetamine exposure. Given that midline craniofacial anomalies are hallmarks of FAS, smaller CC may provide an early indicator of alcohol‐related cognitive deficits linked to this brain structure in childhood.