Pregnancy and childbirth are normal conditions, but complications and adverse outcomes are common. Both genetic and environmental factors influence the course of pregnancy. Genetic epidemiologic research into pregnancy outcomes could be strengthened by the use of common measures, which would allow data from different studies to be combined or compared. Here, we introduce perinatal researchers to the PhenX Toolkit and the Collections related to pregnancy and childbirth.
The Pregnancy and Birth Collections were drawn from measures in the PhenX Tooklit. The lead author selected a list of measures for each Collection, which was reviewed by the remaining authors and revised on the basis of their comments. We chose the measures we thought were most relevant for perinatal research and had been linked most strongly to perinatal outcomes.
The Pregnancy and Birth Health Conditions Collection includes 24 measures related to pregnancy and fertility history, maternal complications, and infant complications. The Pregnancy and Birth Outcome Risk Factors Collection includes 43 measures of chemical, medical, psychosocial, and personal factors associated with pregnancy outcomes.
The biological complexity of pregnancy and its sensitivity to environmental and genomic influences suggest that multidisciplinary approaches are needed to generate new insights or practical interventions. To fully exploit new research methods and resources, we encourage the biomedical research community to adopt standard measures to facilitate pooled or meta-analyses.
Pregnancy; Birth; Risk factors; Pregnancy outcomes
Physiological correlates of behavioral and emotional problems, substance use onset and initiation of risky sexual behavior have not been studied in adolescents with prenatal drug exposure. We studied the concordance between baseline respiratory sinus arrhythmia (RSA) at age 3 and baseline Cortisol levels at age 11. We hypothesized that children who showed concordance between RSA and Cortisol would have lower neurobehavioral disinhibition scores which would in turn predict age of substance use onset and first sexual intercourse. The sample included 860 children aged 16 years participating in the Maternal Lifestyle Study, a multisite longitudinal study of children with prenatal exposure to cocaine and other substances. Structural equation modeling was used to test pathways between prenatal substance exposure, early adversity, baseline RSA, baseline Cortisol, neurobehavioral disinhibition, drug use, and sexual behavior outcomes. Concordance was studied by examining separate male and female models in which there were statistically significant interactions between baseline RSA and Cortisol. Prenatal substance exposure was operationalized as the number of substances to which the child was exposed. An adversity score was computed based on caregiver postnatal substance use, depression and psychological distress, number of caregiver changes, socioeconomic and poverty status, quality of the home environment, and child history of protective service involvement, abuse and neglect. RSA and Cortisol were measured during a baseline period prior to the beginning of a task. Neurobehavioral disinhibition, based on composite scores of behavioral dysregulation and executive dysfunction, substance use and sexual behavior were derived from questionnaires and cognitive tests administered to the child. Findings were sex specific. In females, those with discordance between RSA and Cortisol (high RSA and low Cortisol or low RSA and high Cortisol) had the most executive dysfunction which, in turn, predicted earlier initiation of alcohol by age 16. Among boys, there also existed a significant baseline RSA by baseline Cortisol interaction. Boys with low baseline RSA and high baseline Cortisol had the highest levels of behavioral dysregulation. This increase in behavioral dysregulation was in turn related to initiation of alcohol use by age 16 and lower age of first sexual intercourse. We found sex-specific pathways to the initiation of alcohol use and risky sexual behavior through the combined activity of parasympathetic and neuroendocrine functioning. The study of multiple physiological systems may suggest new pathways to the study of age of onset of substance use and engagement in risky sexual behavior in adolescents.
Cortisol; Heart rate variability; Adversity; Sex differences; Teenage substance use onset; Behavioral problems; Executive function
Neurobehavioral disinhibition (ND) is a complex condition reflecting a wide range of problems involving difficulties with emotion regulation and behavior control. Respiratory sinus arrhythmia (RSA) is a physiological correlate of emotion regulation that has been studied in a variety of at-risk populations; however, there are no studies of RSA in children with ND. Data were drawn from a prospective longitudinal study of prenatal substance exposure that included 1,073 participants. Baseline RSA and RSA reactivity to an attention-demanding task were assessed at 3, 4, 5, and 6 years. ND was assessed at ages 8/9, 11, and 13/14 years via behavioral dysregulation and executive dysfunction composite measures. Greater exposure to early adversity was related to less RSA reactivity at 3 years, increases in RSA reactivity from ages 3 to 6 years, and increased behavioral dysregulation from ages 8/9 to 13/14. RSA reactivity was examined as a moderator of the association between early adversity and changes in ND. A significant Early Adversity × RSA Reactivity quadratic interaction revealed that children with decelerations in RSA reactivity exhibited increases in behavioral dysregulation, regardless of their exposure to early adversity. However, greater exposure to early adversity was related to greater increases in behavioral dysregulation, but only if children exhibited accelerations in RSA reactivity from ages 3 to 6 years. The results contribute to our understanding of how interactions across multiple levels of analysis contribute to the development of ND.
To examine the autonomic nervous system and neurobehavioral response to a sustained visual attention challenge among 1-month old infants with prenatal substance exposure.
We measured heart rate (HR), respiratory sinus arrhythmia (RSA), and neurobehavior during sustained visual orientation tasks included in the NICU Network Neurobehavioral Scale (NNNS) in 1,129, 1-month infants with prenatal substance exposure. Four groups were compared: infants with prenatal cocaine and opiate exposure, infants with cocaine exposure, infants with opiate exposure, and infants with exposure to other substances (i.e. alcohol, marijuana, and tobacco).
Infants with prenatal cocaine and opiate exposure had the highest HRs and lowest levels of RSA during a sustained visual attention procedure compared with the other three groups. Infants with prenatal cocaine and opiate exposure had poorer quality of movement and more hypertonicity during the NNNS exam compared with the other three exposure groups. Infants with prenatal cocaine and opiate exposure had more nonoptimal reflexes and stress/abstinence signs compared with infants with prenatal cocaine exposure only and infants with prenatal exposure to alcohol, tobacco, and marijuana.
Problems with arousal regulation were identified among infants with prenatal substance exposure. Autonomic dysregulation has been implicated as a mechanism by which these difficulties occur. Our results suggest that infants with both prenatal cocaine and opiate exposure have the greatest autonomic response to the challenge of a sustained visual attention task, which may place these infants at risk for developing problems associated with physiological and behavioral regulation, a necessary prerequisite for early learning.
in utero drug exposure; physiology; neurobehavioral
High-risk environments characterized by familial substance use, poverty, inadequate parental monitoring, and violence exposure are associated with an increased propensity for adolescents to engage in risk-taking behaviors (e.g., substance use, sexual behavior, and delinquency). However, additional factors such as drug exposure in utero and deficits in inhibitory control among drug-exposed youth may further influence the likelihood that adolescents in high-risk environments will engage in risk-taking behavior. This study examined the influence of prenatal substance exposure, inhibitory control, and sociodemographic/environmental risk factors on risk-taking behaviors in a large cohort of adolescents with and without prenatal cocaine exposure (PCE).
Risk-taking behavior (delinquency, substance use, and sexual activity) was assessed in 963 adolescents (433 cocaine-exposed, 530 nonexposed) at 15 years of age.
PCE predicted later arrests and early onset of sexual behavior in controlled analyses. Associations were partially mediated, however, by adolescent inhibitory control problems. PCE was not associated with substance use at this age. In addition, male gender, low parental involvement, and violence exposure were associated with greater odds of engaging in risk-taking behavior across the observed domains.
Study findings substantiate concern regarding the association between prenatal substance exposure and related risk factors and the long-term outcomes of exposed youth. Access to the appropriate social, educational, and medical services are essential in preventing and intervening with risk-taking behaviors and the potential consequences (e.g., adverse health outcomes, incarceration), especially among high-risk adolescent youth and their families.
prenatal drug exposure; cocaine; adolescence; risk-taking behavior
We employed latent growth curve analysis to examine trajectories of respiratory sinus arrhythmia (RSA) from 3 to 6 years among children with varying levels of prenatal substance exposure and early adversity. Data were drawn from a prospective longitudinal study of prenatal substance exposure that included 1,121 participants. Baseline RSA and RSA reactivity to an attention-demanding task were assessed at 3, 4, 5, and 6 years. Overall, there were significant individual differences in the trajectories of RSA reactivity, but not baseline RSA, across development. Greater levels of prenatal substance exposure, and less exposure to early adversity, were associated with increased RSA reactivity at 3 years, but by 6 years, both were associated with greater RSA reactivity. Prenatal substance exposure had an indirect influence through early adversity on growth in RSA reactivity. Results are in support of and contribute to the framework of allostatic load.
allostatic load; prenatal substance exposure; early adversity; respiratory sinus arrhythmia
We determined the role of risk and protective factors on the trajectories of behavior problems associated with high prenatal cocaine exposure (PCE)/polydrug exposure.
The Maternal Lifestyle Study enrolled 1388 children with or without PCE, assessed through age 15 years. Because most women using cocaine during pregnancy also used other substances, we analyzed for the effects of 4 categories of prenatal drug exposure: high PCE/other drugs (OD), some PCE/OD, OD/no PCE, and no PCE/no OD. Risks and protective factors at individual, family, and community levels that may be associated with behavior outcomes were entered stepwise into latent growth curve models, then replaced by cumulative risk and protective indexes, and finally by a combination of levels of risk and protective indexes. Main outcome measures were the trajectories of externalizing, internalizing, total behavior, and attention problems scores from the Child Behavior Checklist (parent).
A total of 1022 (73.6%) children had known outcomes. High PCE/OD significantly predicted externalizing, total, and attention problems when considering the balance between risk and protective indexes. Some PCE/OD predicted externalizing and attention problems. OD/no PCE also predicted behavior outcomes except for internalizing behavior. High level of protective factors was associated with declining trajectories of problem behavior scores over time, independent of drug exposure and risk index scores.
High PCE/OD is a significant risk for behavior problems in adolescence; protective factors may attenuate its detrimental effects. Clinical practice and public health policies should consider enhancing protective factors while minimizing risks to improve outcomes of drug-exposed children.
behavior problems; cumulative risks; prenatal cocaine exposure; protective factors
In previous work we (Fisher et al., 2011) examined the emergence of neurobehavioral disinhibition (ND) in adolescents with prenatal substance exposure. We computed ND factor scores at three age points (8/9, 11 and 13/14 years) and found that both prenatal substance exposure and early adversity predicted ND. The purpose of the current study was to determine the association between these ND scores and initiation of substance use between ages 8–16 in this cohort as early initiation of substance use has been related to later substance use disorders. Our hypothesis was that prenatal cocaine exposure predisposes the child to ND, which, in turn, is associated with initiation of substance use by age 16.
We studied 386 cocaine exposed and 517 unexposed children followed since birth in a longitudinal study. Five dichotomous variables were computed based on the subject’s report of substance use: alcohol only; tobacco only; marijuana only; illicit substances and any substance.
Cox proportional hazard regression showed that the 8/9 year ND score was related to initiation of alcohol, tobacco, illicit and any substance use but not marijuana use. The trajectory of ND across the three age periods was related to substance use initiation in all five substance use categories. Prenatal cocaine exposure, although initially related to tobacco, marijuana and illicit substance initiation, was no longer significant with ND scores in the models.
Prenatal drug exposure appears to be a risk pathway to ND, which by 8/9 years portends substance use initiation.
neurodevelopmental disinhibition; substance use initiation; prenatal cocaine exposure
Prenatal cocaine exposure (PCE) is associated with blunted stress responsivity within the extrauterine environment. This study investigated the association between PCE and diurnal salivary cortisol levels in preadolescent children characterized by high biological and/or social risk (N = 725). Saliva samples were collected at their home. Analyses revealed no group differences in basal evening or morning cortisol levels; however, children with higher degrees of PCE exhibited blunted overnight increases in cortisol, controlling for additional risk factors. Race and caregiver depression were also associated with diurnal cortisol patterns. While repeated PCE may contribute to alterations in the normal or expected stress response later in life, sociodemographic and environmental factors are likewise important in understanding hormone physiology, especially as more time elapses from the PCE. Anticipating the potential long-term medical, developmental, or behavioral effects of an altered ability to mount a normal protective cortisol stress response is essential in optimizing the outcomes of children with PCE.
The purpose of the current study was to identify and describe strategies available to optimize retention of a high-risk research cohort and assist in the recovery of study participants following participant dropout.
Design and Methods
The Maternal Lifestyle Study (MLS), which investigated the effects of prenatal substance exposure (cocaine or opiates) on child outcome, is a prospective longitudinal follow-up study that extended from birth through 15 years of age. Retention strategies to maximize participation and factors that might negatively impact compliance were examined over the course of five follow-up phases.
At the conclusion of the 15-year visits, MLS had successfully maintained compliance at 76%. Retention rates did not differ by exposure group.
Maintaining ongoing participation of enrolled study subjects is a critical element of any successful longitudinal study. Strategies that can be used to reengage and maintain participants in longitudinal research include persistence, flexibility with scheduling, home visits, long-distance trips, increased incentives, and development of a computerized tracking system. Establishing rapport with families and ensuring confidentiality contributed to overall participant retention. The use of multiple tracking techniques is essential.
Researchers are challenged to maintain participants in longitudinal studies to ensure the integrity of their research.
Longitudinal research; participant retention; tracking; compliance
This study evaluated how enrollment in special education services in 11 year old children relates to prenatal cocaine exposure, psychopathology, and other risk factors.
Participants were 498 children enrolled in The Maternal Lifestyle Study, a prospective, longitudinal, multisite study examining outcomes of children with prenatal cocaine exposure. Logistic regression was used to examine the effect of prenatal cocaine exposure and psychopathology on enrollment in an individualized education plan (a designation specific to children with special education needs), with environmental, maternal, and infant medical variables as covariates.
Prenatal cocaine exposure, an interaction of prenatal cocaine exposure and Oppositional Defiant Disorder, child Attention Deficit Hyperactivity Disorder, parent-reported internalizing behaviors, and teacher-reported externalizing behaviors, predicted enrollment in an individualized education plan. Other statistically significant variables in the model were male gender, low birth weight, being small for gestational age, white race, caregiver change, low socio-economic status, low child intelligence quotient, caregiver depression, and prenatal marijuana exposure.
Prenatal cocaine exposure increased the likelihood of receiving an individualized education plan with adjustment for covariates. Psychopathology also predicted this special education outcome, in combination with and independent of prenatal cocaine exposure.
cocaine; special education; behavior; prenatal substance exposure
The focus of the PhenX (Phenotypes and eXposures) Toolkit is to provide researchers whose expertise lies outside a particular area with key measures identified by experts for uniform use in large-scale genetic studies and other extensive epidemiologic efforts going forward. The current paper specifically addresses the PhenX Toolkit research domain of physical activity and physical fitness (PA/PF), which are often associated with health outcomes. A Working Group (WG) of content experts completed a 6-month consensus process in which they identified a set of 14 high-priority, low-burden, and scientifically supported measures. During this process the WG considered self-reported and objective measures which included the latest technology (e.g., accelerometers, pedometers, heart-rate monitors). They also sought the input of measurement experts and other members of the research community during their deliberations. A majority of the measures include protocols for children (or adolescents), adults, and older adults or are applicable to all ages.
Measures from the PA/PF domain and 20 other domains are publicly available and found at the PhenX Toolkit website, www.phenxtoolkit.org. The use of common measures and protocols across large studies enhances the capacity to combine or compare data across studies, benefitting both PA/PF experts and non-experts. Use of these common measures by the research community should increase statistical power and enhance the ability to answer scientific questions that might have previously gone unanswered.
We previously reported early results of a randomized trial of whole-body hypothermia for neonatal hypoxic–ischemic encephalopathy showing a significant reduction in the rate of death or moderate or severe disability at 18 to 22 months of age. Long-term outcomes are now available.
In the original trial, we assigned infants with moderate or severe encephalopathy to usual care (the control group) or whole-body cooling to an esophageal temperature of 33.5°C for 72 hours, followed by slow rewarming (the hypothermia group). We evaluated cognitive, attention and executive, and visuospatial function; neurologic outcomes; and physical and psychosocial health among participants at 6 to 7 years of age. The primary outcome of the present analyses was death or an IQ score below 70.
Of the 208 trial participants, primary outcome data were available for 190. Of the 97 children in the hypothermia group and the 93 children in the control group, death or an IQ score below 70 occurred in 46 (47%) and 58 (62%), respectively (P = 0.06); death occurred in 27 (28%) and 41 (44%) (P = 0.04); and death or severe disability occurred in 38 (41%) and 53 (60%) (P = 0.03). Other outcome data were available for the 122 surviving children, 70 in the hypothermia group and 52 in the control group. Moderate or severe disability occurred in 24 of 69 children (35%) and 19 of 50 children (38%), respectively (P = 0.87). Attention–executive dysfunction occurred in 4% and 13%, respectively, of children receiving hypothermia and those receiving usual care (P = 0.19), and visuospatial dysfunction occurred in 4% and 3% (P = 0.80).
The rate of the combined end point of death or an IQ score of less than 70 at 6 to 7 years of age was lower among children undergoing whole-body hypothermia than among those undergoing usual care, but the differences were not significant. However, hypothermia resulted in lower death rates and did not increase rates of severe disability among survivors. (Funded by the National Institutes of Health and the Eunice Kennedy Shriver NICHD Neonatal Research Network; ClinicalTrials.gov number, NCT00005772.)
The negative effects of prenatal substance exposure on neurobiological and psychological development and of early adversity are clear, but little is known about their combined effects. In this study, multilevel analyses of the effects of prenatal substance exposure and early adversity on the emergence of neurobehavioral disinhibition in adolescence were conducted. Neurobehavioral disinhibition has previously been observed to occur frequently in multiproblem youth from high-risk backgrounds. In the present study, neurobehavioral disinhibition was assessed via behavioral dysregulation and poor executive function composite measures. Data were drawn from a prospective longitudinal investigation of prenatal substance exposure that included 1073 participants followed from birth through adolescence. The results from latent growth modeling analyses showed mean stability but significant individual differences in behavioral dysregulation and mean decline with individual differences in executive function difficulties. Prior behavioral dysregulation predicted increased executive function difficulties. Prenatal drug use predicted the emergence and growth in neurobehavioral disinhibition across adolescence (directly for behavioral dysregulation and indirectly for executive function difficulties via early adversity and behavioral dysregulation). Prenatal drug use and early adversity exhibited unique effects on growth in behavioral dysregulation; early adversity uniquely predicted executive function difficulties. These results are discussed in terms of implications for theory development, social policy, and prevention science.
Stressful experiences such as childhood trauma and depressive symptoms have both been implicated in the initiation of drug use; however, longitudinal designs have not yet been used to elucidate their respective roles to better understand the causal sequence. In the present study, a sensitivity analysis was conducted using two mediation strategies to examine how this sequence may differ by various levels of statistical control, including (1) the standard mediational model in which the effect of lifetime traumatic stressors (Year 1) on the onset of drug use (Years 3 and 4) is mediated by levels of depressive symptoms (Year 2); and (2) a stronger test of causality such that the effect of lifetime traumatic stressors (Year 1) on the onset of drug use (Years 3 and 4) was mediated by changes in depressive symptoms (Year 1 to 2), measured by a residualized change score that controlled for levels in Year 1. Two types of trauma were studied in a community-based study of 489 Hispanic preadolescents (aged 10–12): (a) the number of lifetime traumatic stressors and (b) seven specific lifetime stressors. We also controlled for new onset traumatic stressors occurring between Years 1 and 2. Primary findings indicate that drug use initiation during early adolescence (e.g., ages 14–16) may not be tied to immediate proximal perturbations in risk factors, such as traumatic experiences and depressive symptoms. Rather, the effects of trauma on depression in this sample appear to be established earlier in childhood (ages 10–14 or younger) and persist in a relatively stable manner into middle adolescence when the risk for drug use may be heightened.
drug use; youth; childhood trauma; depression; mediation; prevention
To examine screening results obtained by serial annual behavioral assessment of children with prenatal drug exposure.
The Maternal Lifestyle Study enrolled children with prenatal cocaine exposure (PCE) at birth for longitudinal assessments of developmental, behavioral, and health outcomes. At 8, 9, 10, 11, and 12 years of age, caregivers rated participants on the Pediatric Symptom Checklist (PSC). Serial PSC results were compared to an established broad-based behavioral measure at 9, 11, and 13 years. PSC results were analyzed for 1,081 children who had at least 2 annual screens during the 5-year time span. Most subjects (87%) had 4 or more annual screens rated by the same caregiver (80%). PSC scores (and Positive screens) over time were compared at different time points for those with and without PCE. Covariates, including demographic factors and exposures to certain other substances, were controlled.
Children with PCE had significantly higher scores overall, with more Positive screens for behavior problems than children without PCE. Children with PCE had more externalizing behavior problems. Children exposed to tobacco pre- and post-natally also showed higher PSC scores. Over time, PSC scores differed slightly from the 8-year scores, without clear directional trend. Earlier PSC results predicted later behavioral outcomes.
Findings of increased total PSC scores and Positive PSC screens for behavioral concerns in this group of children with prenatal substance exposure support the growing body of evidence that additional attention to identification of mental health problems may be warranted in this high-risk group.
Behavior disorder; child behavior; mental health; screening; prenatal cocaine exposure; Pediatric Symptom Checklist
We previously reported an association between prenatal cocaine exposure (PCE) and childhood behavior problems as observed by the parent or caretaker. However, these behavior problems may not manifest in a structured environment, such as a school setting.
We determined whether there is an association between PCE and school behavior problems and whether ratings of behavior problems from the teacher differ from those noted by the parent or caretaker.
The Maternal Lifestyle Study, a multicenter study, enrolled 1388 children with and without PCE at one month of age for longitudinal assessment. Teachers masked to prenatal drug exposure status completed the Teacher Report Form (TRF/6-18) when children were 7, 9, and 11 years old. We also administered the Child Behavior Checklist-parent report (CBCL) to the parent/caretaker at same ages and then at 13 years. We performed latent growth curve modeling to determine whether high PCE will predict externalizing, internalizing, total behavior, and attention problems at 7 years of age and whether changes in problems' scores over time differ between those exposed and non-exposed from both teacher and parent report. Besides levels of PCE as predictors, we controlled for the following covariates, namely: site, child characteristics (gender and other prenatal drug exposures), family level influences (maternal age, depression and psychological symptomatology, continuing drug use, exposure to domestic violence, home environment, and socioeconomic status), and community level factors (neighborhood and community violence).
The mean behavior problem T scores from the teacher report were significantly higher than ratings by the parent or caretaker. Latent growth curve modeling revealed a significant relationship between intercepts of problem T scores from teacher and parent ratings; i.e., children that were rated poorly by teachers were also rated poorly by their parent/caretaker or vice versa. After controlling for covariates, we found high PCE to be a significant predictor of with higher externalizing behavior problem T scores from both parent and teacher report at 7 years (p=0.034 and p=0.021, respectively) in comparison to non-PCE children. These differences in scores from either teacher or caregiver were stable through subsequent years or did not change significantly over time. Boys had higher T scores than girls on internalizing and total problems by caretaker report; they also had significantly higher T scores for internalizing, total, and attention problems by teacher ratings; the difference was marginally significant for externalizing behavior (p=0.070). Caretaker postnatal use of tobacco, depression, and community violence were significant predictors of all behavior problems rated by parent/caretaker, while lower scores on the home environment predicted all behavior outcomes by the teacher report.
Children with high PCE are likely to manifest externalizing behavior problems; their behavior problem scores at 7 years from either report of teacher or parent remained higher than scores of non-exposed children on subsequent years. Screening and identification of behavior problems at earlier ages could make possible initiation of intervention, while considering the likely effects of other confounders.
The potential for genome-wide association studies to relate phenotypes to specific genetic variation is greatly increased when data can be combined or compared across multiple studies. To facilitate replication and validation across studies, RTI International (Research Triangle Park, North Carolina) and the National Human Genome Research Institute (Bethesda, Maryland) are collaborating on the consensus measures for Phenotypes and eXposures (PhenX) project. The goal of PhenX is to identify 15 high-priority, well-established, and broadly applicable measures for each of 21 research domains. PhenX measures are selected by working groups of domain experts using a consensus process that includes input from the scientific community. The selected measures are then made freely available to the scientific community via the PhenX Toolkit. Thus, the PhenX Toolkit provides the research community with a core set of high-quality, well-established, low-burden measures intended for use in large-scale genomic studies. PhenX measures will have the most impact when included at the experimental design stage. The PhenX Toolkit also includes links to standards and resources in an effort to facilitate data harmonization to legacy data. Broad acceptance and use of PhenX measures will promote cross-study comparisons to increase statistical power for identifying and replicating variants associated with complex diseases and with gene-gene and gene-environment interactions.
environmental exposure; epidemiologic methods; genetic research; genetics; genome-wide association study; meta-analysis as topic; phenotype; research design
Prenatal cocaine exposure has been linked to intrauterine growth retardation and poor birth outcomes; little is known about the effects on longer-term medical outcomes, such as overweight status and hypertension in childhood. Our objective was to examine the association between prenatal cocaine exposure and body mass index and blood pressure at 9 years of age among children followed prospectively in a multi-site longitudinal study evaluating the impact of maternal lifestyle during pregnancy on childhood outcome.
This analysis includes 880 children (277 cocaine exposed and 603 with no cocaine exposure) with blood pressure, height, and weight measurements at 9 years of age. Regression analyses were conducted to explore the relationship between prenatal cocaine exposure and body mass index and blood pressure at 9 years of age after controlling for demographics, other drug exposure, birth weight, maternal weight, infant postnatal weight gain, and childhood television viewing, exercise and dietary habits at 9 years. Path analyses were used to further explore these relationships.
At 9 years of age, 15% of the children were pre-hypertensive and 19% were hypertensive; 16% were at risk for overweight status and 21% were overweight. A small percentage of women were exposed to high levels of prenatal cocaine throughout pregnancy. Among children born to these women, a higher body mass index was noted. Path analysis suggested that high cocaine exposure has an indirect effect on systolic and diastolic blood pressure that is mediated through its effect on body mass index.
High levels of in-utero cocaine exposure are a marker for elevated body mass index and blood pressure among children born full term.
Prenatal cocaine exposure; Body mass index; Childhood hypertension; Overweight; Obesity
To examine the relationships between sleep problems and prenatal exposure to cocaine, opiates, marijuana, alcohol, and nicotine in children 1 month to 12 years of age.
Sleep data was collected by maternal report in a prospective longitudinal follow-up of children participating in the Maternal Lifestyle multisite study.
Hospital based research centers in Providence, RI, Miami, FL, Detroit, MI, and Memphis, TN
There were 808 participants: 374 exposed to cocaine and/or opiates; 434 comparison.
Prenatal cocaine, opiate, marijuana, alcohol, and nicotine exposure.
Sleep problems in early, middle, and late childhood, assessed as composites of maternal report items.
Of the five substances, prenatal nicotine exposure was the only unique predictor of sleep problems (B = .074, R2 Δ = .008, p = .012) with adjustment for covariates including SES, marital status, physical abuse, prenatal medical care, and postnatal cigarette smoke exposure.
Prenatal exposure to nicotine was positively associated with children's sleep problems persisting throughout the first 12 years of life. Targeting this group of children for educational and behavioral efforts to prevent and treat sleep problems is merited given that good sleep may serve as a protective factor for other developmental outcomes.