The National Children's Study: a 21-year prospective study of 100,000 American children

Effectiveness of Self-Collected, Ambient Temperature-Preserved Nasal Swabs Compared to Samples Collected by Trained Staff for Genotyping of Respiratory Viruses by Shotgun RNA Sequencing: Comparative Study

BACKGROUND

The SARS-CoV-2 pandemic has underscored the need for field specimen collection and transport to diagnostic and public health laboratories. Self-collected nasal swabs transported without dependency on a cold chain have the potential to remove critical barriers to testing, expand testing capacity, and reduce opportunities for exposure of health professionals in the context of a pandemic.

OBJECTIVE

We compared nasal swab collection by study participants from themselves and their children at home to collection by trained research staff.

METHODS

Each adult participant collected 1 nasal swab, sampling both nares with the single swab, after which they collected 1 nasal swab from 1 child. After all the participant samples were collected for the household, the research staff member collected a separate single duplicate sample from each individual. Immediately after the sample collection, the adult participants completed a questionnaire about the acceptability of the sampling procedures. Swabs were placed in temperature-stable preservative and respiratory viruses were detected by shotgun RNA sequencing, enabling viral genome analysis.

RESULTS

In total, 21 households participated in the study, each with 1 adult and 1 child, yielding 42 individuals with paired samples. Study participants reported that self-collection was acceptable. Agreement between identified respiratory viruses in both swabs by RNA sequencing demonstrated that adequate collection technique was achieved by brief instructions.

CONCLUSIONS

Our results support the feasibility of a scalable and convenient means for the identification of respiratory viruses and implementation in pandemic preparedness for novel respiratory pathogens.

Geographic and demographic variability in serum PFAS concentrations for pregnant women in the United States

BACKGROUND

While major pathways of human PFAS exposure are thought to be drinking water and diet, other pathways and sources have also been shown to contribute to a person's cumulative exposure. However, the degree of contribution of these other sources to PFAS body burdens is still not well understood and occurrence data for PFAS in conssumer products and household materials are sparse. Questionnaire data concordant with biomonitoring may improve understanding of associations between other PFAS exposure pathways and exposure in human populations.

OBJECTIVE

This study aims to better understand maternal and early-life exposures to PFAS from various potential sources and pathways in the context of household and community level characteristics.

METHODS

PFAS data from the National Children's Study (NCS) Vanguard Data and Sample Archive Access System were analyzed from serum of 427 pregnant women residing in 7 counties throughout the United States. Location and self-reported questionnaire responses were used to analyze variability in serum concentrations based on demographics, housing characteristics, behaviors, and geography. Spatial mapping analyses incorporated publicly available data to further hypothesize potential sources of exposure in two NCS counties.

RESULTS

Location was associated with serum concentrations for all PFAS chemicals measured. Questionnaire responses for race/ethnicity, income, education level, number of household members, drinking water source, home age, and fast-food consumption were associated with PFAS levels. Statistical differences were observed between participants with the same questionnaire responses but in different locations. Spatial mapping analyses suggested that participants' proximity to local point sources can overshadow expected trends with demographic information.

SIGNIFICANCE

By increasing understanding of maternal and early-life PFAS exposures from various potential sources and pathways, as well as highlighting the importance of proximity to potential sources in identifying vulnerable populations and locations, this work reveals environmental justice considerations and contributes to risk management strategies that maximize public health protection.

IMPACT

This work increases understanding of maternal and early-life PFAS exposures, reveals environmental justice considerations, and contributes to study design and risk management strategies.

Gene-environment interactions related to maternal exposure to environmental and lifestyle-related chemicals during pregnancy and the resulting adverse fetal growth: a review

Background

There are only limited numbers of reviews on the association of maternal-child genetic polymorphisms and environmental and lifestyle-related chemical exposure during pregnancy with adverse fetal growth. Thus, this article aims to review: (1) the effect of associations between the above highlighted factors on adverse fetal growth and (2) recent birth cohort studies regarding environmental health risks.

Methods

Based on a search of the PubMed database through August 2021, 68 epidemiological studies on gene-environment interactions, focusing on the association between environmental and lifestyle-related chemical exposure and adverse fetal growth was identified. Moreover, we also reviewed recent worldwide birth cohort studies regarding environmental health risks.

Results

Thirty studies examined gene-smoking associations with adverse fetal growth. Sixteen maternal genes significantly modified the association between maternal smoking and adverse fetal growth. Two genes significantly related with this association were detected in infants. Moreover, the maternal genes that significantly interacted with maternal smoking during pregnancy were cytochrome P450 1A1 (CYP1A1), X-ray repair cross-complementing protein 3 (XRCC3), interleukin 6 (IL6), interleukin 1 beta (IL1B), human leukocyte antigen (HLA) DQ alpha 1 (HLA-DQA1), HLA DQ beta 1 (HLA-DQB1), and nicotinic acetylcholine receptor. Fetal genes that had significant interactions with maternal smoking during pregnancy were glutathione S-transferase theta 1 (GSTT1) and fat mass and obesity-associated protein (FTO). Thirty-eight studies examined the association between chemical exposures and adverse fetal growth. In 62 of the 68 epidemiological studies (91.2%), a significant association was found with adverse fetal growth. Across the studies, there was a wide variation in the analytical methods used, especially with respect to the genetic polymorphisms of interest, environmental and lifestyle-related chemicals examined, and the study design used to estimate the gene-environment interactions. It was also found that a consistently increasing number of European and worldwide large-scale birth cohort studies on environmental health risks have been conducted since approximately 1996.

Conclusion

There is some evidence to suggest the importance of gene-environment interactions on adverse fetal growth. The current knowledge on gene-environment interactions will help guide future studies on the combined effects of maternal-child genetic polymorphisms and exposure to environmental and lifestyle-related chemicals during pregnancy.

Supplementary information

The online version contains supplementary material available at https://doi.org/10.1265/ehpm.21-00033.

Food additives in childhood: a review on consumption and health consequences

OBJECTIVE

To discuss the context of scientific publications on the consumption of food additives by children and the possible health consequences in this age group.

METHODS

A literature review, with a search carried out between April 2020 and April 2021 in the Web of Science, Scopus, PubMed and Google Scholar databases, as well as in websites of Brazilian and foreign official bodies. Official documents and studies published since 2000 were selected. Keywords related to food additives, children, food consumption, and health were used for the search.

RESULTS

Food additives are substances intentionally added to foods for technological purposes. Processed foods are the main sources of additives in food and their consumption occurs since childhood. It is observed, however, that there are limitations inherent to the scientific method regarding the analysis of consumption and toxicity of food additives in humans, causing scarcity of data in the scientific literature. Additionally, existing data suggest that the additives have a higher toxic potential in children, considering that the body weight in this age group is lower than in adults. This context emphasizes the need to observe the precautionary principle, according to which risks of harm must be prevented.

CONCLUSIONS

This is a scenario in which the literature points to a risk to people's health and, in particular, to children, about whom the duty of protection must be even greater, with absolute priority. Thus, the relevance of an expanded technical-scientific debate regarding the establishment of specific and stricter parameters for children is considered, regarding the consumption and toxicity of additives, as well as the different sources of exposure to these substances.

The Pittsburgh Study: Learning with Communities About Child Health and Thriving

The COVID-19 pandemic has highlighted structural inequities that are barriers to thriving for children in neighborhoods with concentrated disadvantage. Health systems are increasingly addressing health-related social needs. The “Pittsburgh Study” is a longitudinal, community-partnered study focused on child and adolescent thriving and racial equity. This initiative will elucidate critical influences on childhood health and thriving, evaluate developmentally appropriate interventions to improve outcomes from birth to high school, and establish a child health data hub. Integration of community members into scientific inquiry, rapid data-to-action cycles, and workforce development are strategies health systems may consider to enhance child health equity.

PediaTrac V.3.0 protocol: a prospective, longitudinal study of the development and validation of a web-based tool to measure and track infant and toddler development from birth through 18 months

INTRODUCTION

The need for an efficient, low-cost, comprehensive measure to track infant/toddler development and treatment outcomes is critical, given the importance of early detection and monitoring. This manuscript describes the protocol for the development and testing of a novel measure, PediaTrac, that collects longitudinal, prospective, multidomain data from parents/caregivers to characterise infant/toddler developmental trajectories in term and preterm infants. PediaTrac, a web-based measure, has the potential to become the standard method for monitoring development and detecting risk in infancy and toddlerhood.

METHODS AND ANALYSES

Using a multisite, prospective design, primarcaregivers will complete PediaTrac V.3.0, a survey tool that queries core domains of early development, including feeding/eating/elimination, sleep, sensorimotor, social/sensory information processing, social/communication/cognition and early relational health. Information also will be obtained about demographic, medical and environmental factors and embedded response bias indices are being developed as part of the measure. Using an approach that systematically measures infant/toddler developmental domains during a schedule that corresponds to well-child visits (newborn, 2, 4, 6, 9, 12, 15, 18 months), we will assess 360 caregiver/term infant dyads and 240 caregiver/preterm infant dyads (gestational age <37 weeks). Parameter estimates of our items and latent traits (eg, sensorimotor) will be estimated by theta using item response theory-graded response modelling. Participants also will complete legacy (ie, established) measures of development and caregiver health and functioning, used to provide evidence for construct (discriminant) validity. Predictive validity will be evaluated by examining relationships between the PediaTrac domains and the legacy measures in the total sample and in a subsample of 100 participants who will undergo a neurodevelopmental assessment at 24 months of age.

ETHICS AND DISSEMINATION

This investigation has single Institutional Review Board (IRB) multisite approval from the University of Michigan (IRB HUM00151584). The results will be presented at prominent conferences and published in peer-reviewed scientific journals.

Factors affecting the growth of children till the age of three years with overweight whose mothers have diabetes mellitus: A population-based cohort study

Background

The prevalence of diabetes mellitus (DM) during pregnancy and childhood obesity is increasing worldwide. Factors affecting the growth of children with overweight whose mothers had DM are complicated and inconclusive. Few longitudinal studies have focused on the growth of infants with macrosomia born to mothers with DM and the factors influencing their overweight. This study explored risk factors for childhood overweight/obesity (OWOB) among children of mothers with DM. Perinatal, maternal socio-demographic, infant care, and maternal body weight characteristics as well as child growth until age 3 years were analyzed using a longitudinal design.

Methods

In total, 24,200 pairs of mothers and their children from the Taiwan Birth Cohort Study were included. Combined Taiwan Children Growth Curve report classifications were analyzed for infant growth at birth and at 6, 12, 18, 24, and 36 months old (m/o). A multiple logistic regression analysis with different model settings was used to assess factors affecting the growth of high birth weight children of mothers with diabetic mellitus (HODM).

Results

Children in the HODM group had a higher average body weight than did those in the non-DM group at different age stages. Relative to the non-DM group, weight gain in the HODM group was slower before 18 m/o but faster from 18 to 36 m/o, particularly after 24 m/o. Maternal DM was a major risk factor for childhood OWOB (odds ratio [OR]: 3.25–3.95). After adjustment for related confounders, the OR was 2.19–3.17. Maternal overweight or obesity and higher gestational weight gain were greater risk factors for childhood OWOB at 3 years old after adjusted maternal DM and other selected confounders (OR: 1.45 and 1.23, respectively). Breastfeeding until 6 m/o was a protective factor against childhood OWOB (OR: 0.95). The HODM and non-DM groups did not differ significantly in perinatal, maternal socio-demographic, or infant care characteristics.

Conclusions

Maternal DM is a major factor of childhood OWOB. Maternal body weight before and after pregnancy affects childhood OWOB, and this effect increases with the child’s age.

Tehran environmental and neurodevelopmental disorders (TEND) cohort study: Phase I, feasibility assessment

PURPOSE

To advance knowledge about childhood neurodevelopmental disorders and study their environmental determinants, we conducted a study in Tehran, Iran to assess the feasibility of prospective birth cohort study.

METHODS

We evaluated participation of pregnant women, feasibility of sampling biological material, and health care services availability in Tehran in four steps: (1) first trimester of pregnancy; (2) third trimester of pregnancy; (3) at delivery; and (4) two to three months after delivery. We collected related data through questionnaires, also various biological samples were obtained from mothers (blood, urine, milk and nails-hands and feet) and newborns (umbilical cord blood, meconium, and urine samples) from February 2016 to October 2017.

RESULTS

overall 838 eligible pregnant women were approached. The participation rate was 206(25%) in our study and about 185(90%) of subjects were recruited in hospitals. Out of 206 participants in the first trimester, blood, urine, hand nail, and foot nail samples were collected from 206(100%),193(93%), 205(99%), and 205(99%), respectively. These values dropped to 65(54%), 83(69%), 84(70%), and 84(70%) for the remaining participants 120(58%) in the third trimester, respectively. Also, we gathered milk samples from 125(60%) of mothers at two to three months after delivery.

CONCLUSION

Our findings suggest that hospitals were better places for recruitment of subjects in a birth cohort in Tehran. We further concluded that birth cohort study recruitment can be improved by choosing appropriate gestational ages. Obtaining the newborn's urine, meconium, and umbilical cord blood were challenging procedures and require good collaboration between hospital staff and researchers.

The PRIDE Study: Evaluation of online methods of data collection

BACKGROUND

Large birth cohort studies are extremely valuable in assessing associations between early life exposures and long-term outcomes. Establishing new birth cohorts is challenging due to declining participation rates. Online methods of data collection may increase feasibility, but have not been evaluated thoroughly.

OBJECTIVE

The primary objective of the ongoing PRegnancy and Infant DEvelopment (PRIDE) Study is to identify exposures during pregnancy and in early life that may affect short-term or long-term health of mother and/or child. In this manuscript, we aimed to evaluate methods of recruitment and online data collection applied.

POPULATION

Dutch women aged ≥18 years in early pregnancy.

DESIGN

Prospective cohort study.

METHODS

Initially, only prenatal care providers recruited participants, but alternative recruitment methods were added as a result of disappointing participation rates, including collaboration with "Moeders voor Moeders" (organisation that visits women in early pregnancy) and Facebook advertisements. Data on demographic characteristics, obstetric history, maternal health, life style factors, occupational exposures, nutrition, pregnancy complications, and infant outcomes are primarily collected through Web-based questionnaires at multiple time points during and after pregnancy. Additional data collection components include paternal questionnaires, blood and saliva sampling, and linkage to medical records.

PRELIMINARY RESULTS

By September 2019, 9573 women were included in the PRIDE Study, of which 1.3% completed paper-based questionnaires. Mean age of the women analysed was 30.6 years, 71.1% had a high level of education, 57.2% were primiparae, and mean gestational age at enrolment was 9.9 (range 3, 37) weeks, with slight differences between recruitment methods. Pregnancy outcome was known for 89.8%. Retention rate at 6 months after the estimated date of delivery was estimated at 70%. Multiple validation studies conducted within the PRIDE Study indicated high data quality.

CONCLUSION(S)

Although challenging and time-consuming, online methods for recruitment and data collection may enable the establishment of new birth cohort studies.

Approach to High Volume Enrollment in Clinical Research: Experiences from an All of Us Research Program Site

Clinical trials and cohort studies are required to meet target recruitment of study participants within stipulated timelines, especially when the priority is to include populations traditionally unrepresented in biomedical research. By the third quarter of 2019, the University of Arizona‐Banner Health Provider Organization (UA‐Banner HPO) has enrolled > 30,000 core participants into the All of Us Research Program (AoURP), the research cohort of the Precision Medicine Initiative. The majority of enrolled participants meet the criteria for individuals under‐represented in biomedical research. The enrollment goals were calculated based on a target of 20,000 as set by the National Institutes of Health and our health provider organization achieved enrollment numbers between 17% and 86% above the targeted daily enrollment. We evaluated enrollment methods and challenges to enrollments encountered by the UA‐Banner Health Provider Organization into the AoURP. Challenges to enrollment centered around the need for high‐touch engagement methods, time investment necessary for stakeholder inclusion, and the use of purely digital enrollment methods especially in populations under‐represented in biomedical research. These challenges occurred at the level of the individual, provider, institutions, and community, and cumulatively impacted participant enrollment. Successful strategies for engagement and enrollment leveraged provider partners as advocates for the program. For high‐volume enrollment in clinical research, it is important to engage leaders in the healthcare setting, patient providers, and tailor engagement and enrollment to potential participant needs. We emphasize the need for precision engagement and enrollment methods tailored to individual needs.

Screening for Pregnancy Status in a Population-Based Sample: Characteristics Associated with Item Nonresponse

OBJECTIVES

Population-based recruitment of a cohort of women who are currently pregnant or who may become pregnant in a given timeframe presents challenges unique to identifying pregnancy status or the likelihood of future pregnancy. Little is known about the performance of individual eligibility items on pregnancy screeners although they are critical to participant recruitment. This paper examined the patterns and respondent characteristics of key pregnancy screener items used in a large national study.

METHODS

Cross-sectional analyses were conducted. Descriptive statistics and multivariable logistic regression models were used to examine nonresponse patterns to three questions (currently pregnant, trying to get pregnant and able to get pregnant). The questions were asked of 50,529 women in 17 locations across the US, as part of eligibility screening for the National Children's Study Vanguard Study household-based recruitment.

RESULTS

Most respondents were willing to provide information about current pregnancy, trying, and able to get pregnant: 99.3% of respondents answered all three questions and 97.4% provided meaningful answers. Nonresponse ranged from 0.3 to 2.5% for individual items. Multivariable logistic regression results identified small but statistically significant differences in nonresponse by respondent age, marital status, race/ethnicity-language, and household-based recruitment group.

CONCLUSIONS FOR PRACTICE

The high levels of response to pregnancy-related items are impressive considering that the eligibility questions were fairly sensitive, were administered at households, and were not part of a respondent-initiated encounter.

Development and validation of PediaTrac™: A web-based tool to track developing infants

OBJECTIVE

PediaTrac™, a 363-item web-based tool to track infant development, administered in modules of ∼40-items per sampling period, newborn (NB), 2--, 4--, 6--, 9-- and 12--months was validated. Caregivers answered demographic, medical, and environmental questions, and questions covering the sensorimotor, feeding/eating, sleep, speech/language, cognition, social-emotional, and attachment domains.

METHODS

Expert Panel Reviews and Cognitive Interviews (CI) were conducted to validate the item bank. Classical Test Theory (CTT) and Item Response Theory (IRT) methods were employed to examine the dimensionality and psychometric properties of PediaTrac with pooled longitudinal and cross-sectional cohorts (N = 132).

RESULTS

Intraclass correlation coefficients (ICC) for the Expert Panel Review revealed moderate agreement at 6 -months and good reliability at other sampling periods. ICC estimates for CI revealed moderate reliability regarding clarity of the items at NB and 4 months, good reliability at 2--, 9-- and 12--months and excellent reliability at 6 -months. CTT revealed good coefficient alpha estimates (α ≥ 0.77 for five of the six ages) for the Social-Emotional/Communication, Attachment (α ≥ 0.89 for all ages), and Sensorimotor (α ≥ 0.75 at 6-months) domains, revealing the need for better targeting of sensorimotor items. IRT modeling revealed good reliability (r = 0.85-0.95) for three distinct domains (Feeding/Eating, Social-Emotional/Communication and Attachment) and four subdomains (Feeding Breast/Formula, Feeding Solid Food, Social-Emotional Information Processing, Communication/Cognition). Convergent and discriminant construct validity were demonstrated between our IRT-modeled domains and constructs derived from existing developmental, behavioral and caregiver measures. Our Attachment domain was significantly correlated with existing measures at the NB and 2-month periods, while the Social-Emotional/Communication domain was highly correlated with similar constructs at the 6-, 9- and 12-month periods.

CONCLUSION

PediaTrac has potential for producing novel and effective estimates of infant development via the Sensorimotor, Feeding/Eating, Social-Emotional/Communication and Attachment domains.

The developing world of DOHaD

Since its debut in a ground-breaking report by Barker and Osmond in 1986, the concept of the Developmental Origins of Health and Disease (DOHaD) has been further developed in several aspects. Its methodology and conclusions relating to proposed origins and outcomes of early life events have been developing and spreading internationally. Indeed, the DOHaD concept now seems to have influenced many fields of research. This article aims to briefly review why the DOHaD concept is important in biomedical science, how it has developed, is currently developing, and how it should develop in future.

The effect of prenatal TVOC exposure on birth and infantile weight: the Mothers and Children's Environmental Health study

BACKGROUNDVolatile organic compounds (VOCs) might restrict prenatal and postnatal growth. However, the effect of the exposure of prenatal VOCs on postnatal growth has not been studied sufficiently. Thus, we investigated the relationship between the exposure of total volatile organic compounds (TVOCs) during pregnancy and its effects on postnatal growth.METHODSA total of 383 pregnant participants were enrolled from 2006 to 2008. We investigated maternal characteristics using a questionnaire. Personal air samples of TVOCs were obtained in mid or late pregnancy. After these mothers had given birth, 360 singleton newborns were selected and postnatal follow-up data were collected at 6, 12, 24, and 36 months, as well as anthropometric factors including body weight. Multiple general linear and mixed models were applied for statistical analyses.RESULTSThe mean concentration of prenatal exposure to TVOCs was 284.2 μg/m³ and that of formaldehyde was 81.6 μg/m³. The birth weight of newborns decreased significantly with prenatal TVOC exposure (β=-45.89, P=0.04). The adjusted mean body weight was 300 g lower in the high-TVOC group (⩾75th) compared with that in the low-exposure group (<75th).CONCLUSIONThese results indicate that elevated exposure to TVOCs during the prenatal period may adversely influence early postnatal growth.

State-Level Immunization Information Systems: Potential for Childhood Immunization Data Linkages

Objectives Sources of immunization data include state registries or immunization information systems (IIS), medical records, and surveys. Little is known about the quality of these data sources or the feasibility of using IIS data for research. We assessed the feasibility of collecting immunization information for a national children's health study by accessing existing IIS data and comparing the completeness of these data against medical record abstractions (MRA) and parent report. Staff time needed to obtain IIS and MRA data was assessed. Methods We administered a questionnaire to state-level IIS representatives to ascertain availability and completeness of their data for research and gather information about data formats. We evaluated quality of data from IIS, medical records, and reports from parents of 119 National Children's Study participants at three locations. Results IIS data were comparable to MRA data and both were more complete than parental report. Agreement between IIS and MRA data was greater than between parental report and MRA, suggesting IIS and MRA are better sources than parental report. Obtaining IIS data took less staff time than chart review, making IIS data linkage for research a preferred choice. Conclusions IIS survey results indicate data can be obtained by researchers using data linkages. IIS are an accessible and feasible child immunization information source and these registries reduce reliance on parental report or medical record abstraction. Researchers seeking to link IIS data with large multi-site studies should consider acquiring IIS data, but may need strategies to overcome barriers to data completeness and linkage.

Environmental factors in the development of autism spectrum disorders

Autism spectrum disorders (ASD) are highly heterogeneous developmental conditions characterized by deficits in social interaction, verbal and nonverbal communication, and obsessive/stereotyped patterns of behavior and repetitive movements. Social interaction impairments are the most characteristic deficits in ASD. There is also evidence of impoverished language and empathy, a profound inability to use standard nonverbal behaviors (eye contact, affective expression) to regulate social interactions with others, difficulties in showing empathy, failure to share enjoyment, interests and achievements with others, and a lack of social and emotional reciprocity. In developed countries, it is now reported that 1%-1.5% of children have ASD, and in the US 2015 CDC reports that approximately one in 45 children suffer from ASD. Despite the intense research focus on ASD in the last decade, the underlying etiology remains unknown. Genetic research involving twins and family studies strongly supports a significant contribution of environmental factors in addition to genetic factors in ASD etiology. A comprehensive literature search has implicated several environmental factors associated with the development of ASD. These include pesticides, phthalates, polychlorinated biphenyls, solvents, air pollutants, fragrances, glyphosate and heavy metals, especially aluminum used in vaccines as adjuvant. Importantly, the majority of these toxicants are some of the most common ingredients in cosmetics and herbicides to which almost all of us are regularly exposed to in the form of fragrances, face makeup, cologne, air fresheners, food flavors, detergents, insecticides and herbicides. In this review we describe various scientific data to show the role of environmental factors in ASD.

Consenting postpartum women for use of routinely collected biospecimens and/or future biospecimen collection

The National Children's Study (NCS) Harris County, Texas Study Center participated in the NCS Provider Based Sampling (PBS) substudy of the NCS Vanguard Phase pilot. As part of the hospital-based birth cohort component of the PBS substudy, we conducted a secondary data analysis to evaluate the proportion of postpartum women who consented to future biospecimen collection alone and to both future collection and use of residual birth biospecimens. In phase 1, 32 postpartum women at one hospital were asked to consent only to maternal future biospecimen collection. In phase 2, 40 other postpartum women from the same hospital were asked for an additional consent to use residual clinical biospecimens from the birth event that otherwise would be discarded, including cord blood and maternal blood and urine. Among 103 eligible women, a total of 72 participated. They were 28.3 ± 5.9 years old on average; 58 % were Hispanic; 63 % consented in English, and 37 % in Spanish; 39 % had some college education; 42 % were married; 60 % had an annual family income <$30,000; and 51 % were employed. In phase 1, 59 % consented to future biospecimen collection, and in phase 2, 95 % consented to both future collection and use of at least one residual birth biospecimen, with a difference between phases of 36 % [95 % CI 17-54 %]. Demographic characteristics did not differ among those who did and did not consent. Postpartum women were significantly more likely to grant consent for use of future and residual hospital-obtained biospecimens than future biospecimen collection alone.

Children's Environmental Health: A Brief History

BACKGROUND

Children's environmental health (CEH), the branch of pediatrics that studies the influence of the environment on children's health, has grown substantially in the past 3 decades and become an increasingly visible and important component of pediatric medicine.

GOALS

To trace the historical origins of CEH; to identify factors responsible for its recent growth.

FINDINGS

CEH has historical roots in toxicology, epidemiology, and occupational medicine. It arose in the second half of the 20th century through a melding of insights from pediatric toxicology, nutritional epidemiology, and social science research. Convergent research in these 3 fields has documented children's unique sensitivities to chemical, nutritional, and psychosocial hazards during windows of vulnerability in early development and has shown that early-life exposures can produce disease and disability in childhood and across the life span. Key events in the development of CEH were: 1) formation by the American Academy of Pediatrics in 1957 of a committee on environmental health that has nurtured the growth of the field for 5 decades and evolved into the Council on Environmental Health; 2) observations made in the 1980s that nutritional deficiency in utero increased risk for adult-onset obesity, diabetes, and cardiovascular disease-work that led to the hypothesis of the developmental origins of health and disease; 3) social science research showing that early exposure to psychosocial stress and trauma increases risk for chronic illness; and 4) publication in 1993 by the National Academy of Sciences of a report, Pesticides in the Diets of Infants and Children, which elevated awareness among national policy makers of children's vulnerability to toxic hazards, moved US environmental policy toward protection of children's health, and catalyzed research investment in CEH in the United States and globally.

CONCLUSIONS

CEH has made substantial progress but faces emerging challenges, including new chemicals and pesticides; increasing movement of polluting industries to poor countries where environmental and public health protections are few; and global climate change. In the future, CEH will require continued investment in research and education and will need to adopt an increasingly global perspective.

Impact of preconception enrollment on birth enrollment and timing of exposure assessment in the initial vanguard cohort of the U.S. National Children's Study

Background

The initial vanguard cohort of the U.S. National Children’s Study was a pregnancy and birth cohort study that sought to enroll some women prior to pregnancy, and to assess exposures early in pregnancy.

Methods

During the recruitment phase (2009–2010), geographically based sampling was used to recruit women early in pregnancy and women not currently pregnant, not using contraception and heterosexually active. We assessed the following outcomes for women enrolled preconception and early in pregnancy: yield of births; demographic characteristics of births for different enrollment groups; time to pregnancy for preconception women; and the timing of study visits for exposure assessment.

Results

1399 women were recruited into the initial vanguard cohort: 429 preconception (198 trying for pregnancy, and 231 not trying) and 970 already pregnant. There were 1135 pregnancies (81 % of women) and 922 newborns enrolled (81 % of pregnancies) through September 2012. Preconception women represented 30.6 % of women enrolled, and contributed 14.5 % of births. Among women who gave birth, and who had enrolled preconception trying for pregnancy, 67.3 % were white non-Hispanic, compared to 50.0 % of preconception women not trying for pregnancy, and 61.5 % of pregnant women. Women enrolled preconception who were trying for pregnancy had higher cumulative probability of pregnancy at one year compared to women not trying (adjusted 86 % versus 56 %). Of 165 women enrolled preconception who became pregnant, 19 % had a study visit within 30 days of conception. By 10.5 weeks after conception, 75 % of women enrolled preconception had completed a pregnancy study visit; for women enrolled pregnant, the 75 % threshold was reached at 28.4 weeks.

Conclusions

There were demographic differences in births from women enrolled preconception trying for pregnancy, preconception not trying for pregnancy, or during pregnancy. Time to pregnancy was shorter for women actively trying for pregnancy. Most women enrolled preconception did not have exposure assessment within 30 days of conception, but they did have exposure assessment much earlier during pregnancy than women who enrolled during pregnancy.

Feasibility and informative value of environmental sample collection in the National Children's Vanguard Study

BACKGROUND

Birth cohort studies provide the opportunity to advance understanding of the impact of environmental factors on childhood health and development through prospective collection of environmental samples.

METHODS

We evaluated the feasibility and informative value of the environmental sample collection methodology in the initial pilot phase of the National Children's Study, a planned U.S. environmental birth cohort study. Environmental samples were collected from January 2009-September 2010 at up to three home visits: pre-pregnancy (n=306), pregnancy (n=807), and 6-months postnatal (n=117). Collections included air for particulate matter ≤2.5 µm (PM2.5), nitrogen dioxide, ozone, volatile organic compounds (VOCs), and carbonyls; vacuum dust for allergens/endotoxin; water for VOCs, trihalomethanes (THMs), and haloacetic acids (HAAs); and wipe samples for pesticides, semi-volatile organics, and metals. We characterized feasibility using sample collection rates and times and informative value using analyte detection frequencies (DF).

RESULTS

Among the 1230 home visits, environmental sample collection rates were high across all sample types (mean=89%); all samples except the air PM2.5 samples had collection times <30 min. Informative value was low for water VOCs (median DF=0%) and pesticide floor wipes (median DF=5%). Informative value was moderate for air samples (median DF=35%) and high for water THMs and HAAs (median DF=91% and 75%, respectively).

CONCLUSIONS

Though collection of environmental samples was feasible, some samples (e.g., wipe pesticides and water VOCs) yielded limited information. These results can be used in conjunction with other study design considerations, such as target population size and hypotheses of interest, to inform the method selection of future environmental health birth cohort studies.

Olfactory recognition memory is disrupted in young mice with chronic low-level lead exposure

Chronic developmental lead exposure yielding very low blood lead burden is an unresolved child public health problem. Few studies have attempted to model neurobehavioral changes in young animals following very low level exposure, and studies are needed to identify tests that are sensitive to the neurobehavioral changes that may occur. Mechanisms of action are not yet known however results have suggested that hippocampus/dentate gyrus may be uniquely vulnerable to early chronic low-level lead exposure. This study examined the sensitivity of a novel odor recognition task to differences in pre-adolescent C57BL/6J mice chronically exposed from birth to PND 28, to 0 ppm (control), 30 ppm (low-dose), or 330 ppm (higher-dose) lead acetate (N=33). Blood lead levels (BLLs) determined by ICP-MS ranged from 0.02 to 20.31 μg/dL. Generalized linear mixed model analyses with litter as a random effect showed a significant interaction of BLL×sex. As BLLs increased olfactory recognition memory decreased in males. Among females, non-linear effects were observed at lower but not higher levels of lead exposure. The novel odor detection task is sensitive to effects associated with early chronic low-level lead exposure in young C57BL/6J mice.

Prenatal recruitment of participants for a birth cohort study including cord blood collection: results of a feasibility study in Bremen, Germany

BACKGROUND

Prospective birth cohort studies comprising follow up of children from pregnancy or birth over a long period of time, and collecting various biological samples at different times through the life-course offer a promising approach to enhance etiologic knowledge of various diseases. Especially for those where early lifetime exposures and conditions are thought to play an important role. The collection and storage of biological samples is a critical component in epidemiological studies, notably for research regarding prenatal exposures to various environmental factors as well as for DNA extraction. Our feasibility study for a birth cohort within the scope of etiology of childhood leukemia with prospective sampling of mothers and their future newborns aimed to investigate the willingness of pregnant women to participate in a birth cohort study involving collection of blood and umbilical cord blood samples. The overall aim was to develop practice-based research recommendations for a possible German birth cohort study.

METHODS

The study was conducted in Bremen, Germany, between January 2012 and March 2013. Pregnant women were eligible for recruitment if (i) their expected date of delivery was during the study recruitment phase (September 2012-February 2013), (ii) they planned to give birth at the cooperating hospital's obstetric unit and (iii) their knowledge of the German language was sufficient to understand study materials, details of participation and to fill out the prenatal self-administered questionnaire. Maternal blood and umbilical cord blood samples to be used for later research activities were collected and stored at a stem cell bank already collaborating with the hospital. 22 primary care gynecologists were invited to enroll pregnant women for the study and cooperation with one hospital was established. Expectant women were recruited during the last trimester of pregnancy, either during one of their prenatal care visits at their primary care gynecologist or later on in hospital by the attending obstetricians or project staff.

RESULTS

Of the 22 invited primary care gynecologists requested to enroll pregnant women for the study, 8 gynecologists actually collaborated. A total of 200 eligible women were invited to participate in the study, 48 (24%) of whom agreed. 34 women were enrolled by primary care gynecologists, with one gynecologist enrolling 26 women. Twelve of 14 women recruited via hospitals were enrolled by study staff. A total of 41 women consented to the collection of umbilical cord blood and maternal blood samples, and samples could be stored for 54% of them. Reason for non-participation were the uncertainty whether or not the full study would be conducted and the fact that the participants were not willing to decide for their children whether or not genetic information (cord blood) can be stored for research purposes.

CONCLUSION

Enrolling parents in a birth cohort study that includes biosampling is a challenge, but participation can be improved through close collaboration with primary care gynecologists and maternity hospitals. Cord blood collection may impede participation, especially when maternity hospitals offer an alternative option for cord blood donation.

Gene-environment interplay in common complex diseases: forging an integrative model—recommendations from an NIH workshop

Although it is recognized that many common complex diseases are a result of multiple genetic and environmental risk factors, studies of gene-environment interaction remain a challenge and have had limited success to date. Given the current state-of-the-science, NIH sought input on ways to accelerate investigations of gene-environment interplay in health and disease by inviting experts from a variety of disciplines to give advice about the future direction of gene-environment interaction studies. Participants of the NIH Gene-Environment Interplay Workshop agreed that there is a need for continued emphasis on studies of the interplay between genetic and environmental factors in disease and that studies need to be designed around a multifaceted approach to reflect differences in diseases, exposure attributes, and pertinent stages of human development. The participants indicated that both targeted and agnostic approaches have strengths and weaknesses for evaluating main effects of genetic and environmental factors and their interactions. The unique perspectives represented at the workshop allowed the exploration of diverse study designs and analytical strategies, and conveyed the need for an interdisciplinary approach including data sharing, and data harmonization to fully explore gene-environment interactions. Further, participants also emphasized the continued need for high-quality measures of environmental exposures and new genomic technologies in ongoing and new studies.

2009 H1N1 and seasonal influenza immunization among pregnant women: a comparison of different sources of immunization information

Validity of prenatal immunization data from different sources has not been assessed. We evaluated prenatal 2009 H1N1 and seasonal influenza (FLU) data obtained from state immunization information systems (IIS), medical record abstraction (MRA), and participant recall using medical care logs (NCS-MCL). 2009 H1N1 and FLU data were obtained from IIS and MRA for 325 pregnant women participating in the National Children's Study at three locations (SD/MN, NC, WI). Women recalled immunizations at first pregnancy visit and at 16-17 and 36 weeks' gestation (NCS-MCL). The proportion of women with vaccine information obtainable from each data source was determined, and proportions immunized as determined using different data sources were compared. IIS data were available for 82%, MRA for 97%, and NCS-MCL for 93% of women. No mention of either vaccine occurred in 29% (range 4-48%) of IIS, 40% of MRA (25-59%), and 59% (43-82%) in NCS-MCL. Best agreement between sources was 2009 H1N1 vaccine in MRA versus IIS [kappa (95% CI) of 0.44 (0.32-0.55)], with poorest agreement for FLU in IIS versus NCS-MCL [0.11 (-0.03 to 0.25)]. IIS was the most sensitive method for identifying women receiving 2009 H1N1 vaccine (92%); MRA was most sensitive for FLU vaccine (81%). IIS provided the most complete and sensitive data for 2009 H1N1 immunizations and MRA the most complete and sensitive data for FLU; IIS data were available for a smaller percent of population than MRA. NCS-MCL was the least sensitive method for identifying vaccinated women.

Early chronic lead exposure reduces exploratory activity in young C57BL/6J mice

Research has suggested that chronic low-level lead exposure diminishes neurocognitive function in children. Tests that are sensitive to behavioral effects at lowest levels of lead exposure are needed for the development of animal models. In this study we investigated the effects of chronic low-level lead exposure on exploratory activity (unbaited nose poke task), exploratory ambulation (open field task) and motor coordination (Rotarod task) in pre-adolescent mice. C57BL/6J pups were exposed to 0 ppm (controls), 30 ppm (low-dose) or 230 ppm (high-dose) lead acetate via dams' drinking water administered from birth to postnatal day 28, to achieve a range of blood lead levels (BLLs) from not detectable to 14.84 µg dl(-1) ). At postnatal day 28, mice completed behavioral testing and were killed (n = 61). BLLs were determined by inductively coupled plasma mass spectrometry. The effects of lead exposure on behavior were tested using generalized linear mixed model analyses with BLL, sex and the interaction as fixed effects, and litter as the random effect. BLL predicted decreased exploratory activity and no threshold of effect was apparent. As BLL increased, nose pokes decreased. The C57BL/6J mouse is a useful model for examining effects of early chronic low-level lead exposure on behavior. In the C57BL/6J mouse, the unbaited nose poke task is sensitive to the effects of early chronic low-level lead exposure. This is the first animal study to show behavioral effects in pre-adolescent lead-exposed mice with BLL below 5 µg dl(-1).

GPS-based microenvironment tracker (MicroTrac) model to estimate time-location of individuals for air pollution exposure assessments: model evaluation in central North Carolina

A critical aspect of air pollution exposure assessment is the estimation of the time spent by individuals in various microenvironments (ME). Accounting for the time spent in different ME with different pollutant concentrations can reduce exposure misclassifications, while failure to do so can add uncertainty and bias to risk estimates. In this study, a classification model, called MicroTrac, was developed to estimate time of day and duration spent in eight ME (indoors and outdoors at home, work, school; inside vehicles; other locations) from global positioning system (GPS) data and geocoded building boundaries. Based on a panel study, MicroTrac estimates were compared with 24-h diary data from nine participants, with corresponding GPS data and building boundaries of home, school, and work. MicroTrac correctly classified the ME for 99.5% of the daily time spent by the participants. The capability of MicroTrac could help to reduce the time-location uncertainty in air pollution exposure models and exposure metrics for individuals in health studies.

Recruitment of women in the National Children's Study Initial Vanguard Study

The initial Vanguard Study of the National Children's Study was conducted during 2009-2010 in 7 locations in the United States. A goal was to evaluate the feasibility and yield of a household-based sampling design to recruit pregnant women. A multistage area probability sampling design was used to identify study locations (generally, counties) that were subsequently divided into smaller geographical units, termed segments. Between 7 and 18 segments were selected in each location, and dwelling units within segments were listed. A household-based recruitment process was implemented, which included enumeration of households to identify age-eligible women, pregnancy screening to identify pregnant women eligible for immediate enrollment and nonpregnant women for telephone follow-up, and administration of informed consent to eligible women. After a recruitment period of 17-20 months, 67,181 (89%) households were enumerated, which identified 34,172 (88%) age-eligible women to whom the pregnancy screener was administered. Among those who completed the screener, 2,285 women became eligible for enrollment, of whom 1,399 (61%) enrolled. Although response rates were fairly high at initial contact and among pregnant women, the overall yield was lower than anticipated. In particular, telephone follow-up of nonpregnant women was not a practicable strategy for prospective recruitment of newly pregnant women.

Autism spectrum disorder, flea and tick medication, and adjustments for exposure misclassification: the CHARGE (CHildhood Autism Risks from Genetics and Environment) case-control study

BACKGROUND

The environmental contribution to autism spectrum disorders (ASD) is largely unknown, but household pesticides are receiving increased attention. We examined associations between ASD and maternally-reported use of imidacloprid, a common flea and tick treatment for pets.

METHODS

Bayesian logistic models were used to estimate the association between ASD and imidacloprid and to correct for potential differential exposure misclassification due to recall in a case control study of ASD.

RESULTS

Our analytic dataset included complete information for 262 typically developing controls and 407 children with ASD. Compared with exposure among controls, the odds of prenatal imidacloprid exposure among children with ASD were slightly higher, with an odds ratio (OR) of 1.3 (95% Credible Interval [CrI] 0.78, 2.2). A susceptibility window analysis yielded higher ORs for exposures during pregnancy than for early life exposures, whereas limiting to frequent users of imidacloprid, the OR increased to 2.0 (95% CI 1.0, 3.9).

CONCLUSIONS

Within plausible estimates of sensitivity and specificity, the association could result from exposure misclassification alone. The association between imidacloprid exposure and ASD warrants further investigation, and this work highlights the need for validation studies regarding prenatal exposures in ASD.

Analysis of self-selection bias in a population-based cohort study of autism spectrum disorders

BACKGROUND

This study examined potential self-selection bias in a large pregnancy cohort by comparing exposure-outcome associations from the cohort to similar associations obtained from nationwide registry data. The outcome under study was specialist-confirmed diagnosis of autism spectrum disorders (ASDs).

METHODS

The cohort sample (n = 89 836) was derived from the population-based prospective Norwegian Mother and Child Cohort Study and its substudy of ASDs, the Autism Birth Cohort (ABC) study. The nationwide registry data were derived from the Medical Birth Registry of Norway (n = 507 856). The children were born in 1999–2007, and seven prenatal and perinatal exposures were selected for analyses.

RESULTS

ASDs were reported for 234 (0.26%) children in the cohort and 2072 (0.41%) in the nationwide population. Compared with the nationwide population, the cohort had an under-representation of the youngest women (<25 years), those who had single status, mothers who smoked during pregnancy, and non-users of prenatal folic acid supplements. The ratios of the adjusted odds ratios (ORs) in the cohort over the adjusted ORs in the nationwide population were as follows; primipara pregnancy: 1.39/1.22, prenatal folic acid use: 0.85/0.86, prenatal smoking: 1.20/1.17, preterm birth (<37 weeks): 1.48/1.42, low birthweight (<2500 g): 1.60/1.58, male sex: 4.39/4.59 (unadjusted only); and caesarean section history: 1.03/1.04.

CONCLUSIONS

Associations estimated between ASDs and perinatal and prenatal exposures in the cohort are close to those estimated in the nationwide population. Self-selection does not appear to compromise validity of exposure-outcome associations in the ABC study.

Obesity and reproductive function

Obesity is associated with multiple adverse reproductive outcomes, but the mechanisms involved are largely unknown. Obesity has been referred to as a "complex system," defined as a system of heterogeneous parts interacting in nonlinear ways to influence the behavior of the parts as a whole. Human reproduction is also a complex system; hence the difficulty in identifying the mechanisms linking obesity and adverse reproductive function. This review discusses the adverse reproductive outcomes associated with obesity and the mechanisms involved and concludes with a discussion of public health policy with respect to the treatment of infertility in obese women.

Autism risk factors: genes, environment, and gene-environment interactions

The aim of this review is to summarize the key findings from genetic and epidemiological research, which show that autism is a complex disorder resulting from the combination of genetic and environmental factors. Remarkable advances in the knowledge of genetic causes of autism have resulted from the great efforts made in the field of genetics. The identification of specific alleles contributing to the autism spectrum has supplied important pieces for the autism puzzle. However, many questions remain unanswered, and new questions are raised by recent results. Moreover, given the amount of evidence supporting a significant contribution of environmental factors to autism risk, it is now clear that the search for environmental factors should be reinforced. One aspect of this search that has been neglected so far is the study of interactions between genes and environmental factors.

EpiHealth: a large population-based cohort study for investigation of gene-lifestyle interactions in the pathogenesis of common diseases

The most common diseases affecting middle-aged and elderly subjects in industrialized countries are multigenetic and lifestyle related. Several attempts have been made to study interactions between genes and lifestyle factors, but most such studies lack the power to examine interactions between several genes and several lifestyle components. The primary objective of the EpiHealth cohort study is to provide a resource to study interactions between several genotypes and lifestyle factors in a large cohort (the aim is 300,000 individuals) derived from the Swedish population in the age range of 45-75 years regarding development of common degenerative disorders, such as cardiovascular diseases, cancer, dementia, joint pain, obstructive lung disease, depression, and osteoporotic fractures. The study consists of three parts. First, a collection of data on lifestyle factors by self-assessment using an internet-based questionnaire. Second, a visit to a test center where blood samples are collected and physiological parameters recorded. Third, the sample is followed for occurrence of outcomes using nationwide medical registers. This overview presents the study design and some baseline characteristics from the first year of data collection in the EpiHealth study.

The All Our Babies pregnancy cohort: design, methods, and participant characteristics

Background

The prospective cohort study design is ideal for examining diseases of public health importance, as its inherent temporal nature renders it advantageous for studying early life influences on health outcomes and research questions of aetiological significance. This paper will describe the development and characteristics of the All Our Babies (AOB) study, a prospective pregnancy cohort in Calgary, Alberta, Canada designed to examine determinants of maternal, infant, and child outcomes and identify barriers and facilitators in health care utilization.

Methods

Women were recruited from health care offices, communities, and through Calgary Laboratory Services before 25 weeks gestation from May 2008 to December 2010. Participants completed two questionnaires during pregnancy, a third at 4 months postpartum, and are currently being followed-up with questionnaires at 12, 24, and 36 months. Data was collected on pregnancy history, demographics, lifestyle, health care utilization, physical and mental health, parenting, and child developmental outcomes and milestones. In addition, biological/serological and genetic markers can be extracted from collected maternal and cord blood samples.

Results

A total of 4011 pregnant women were eligible for recruitment into the AOB study. Of this, 3388 women completed at least one survey. The majority of participants were less than 35 years of age, Caucasian, Canadian born, married or in a common-law relationship, well-educated, and reported household incomes above the Calgary median. Women who discontinued after the first survey (n=123) were typically younger, non-Caucasian, foreign-born, had lower education and household income levels, were less likely to be married or in a common-law relationship, and had poor psychosocial health in early pregnancy. In general, AOB participants reflect the pregnant and parenting population at local and provincial levels, and perinatal indicators from the study are comparable to perinatal surveillance data.

Conclusions

The extensive and rich data collected in the AOB cohort provides the opportunity to answer complex questions about the relationships between biology, early experiences, and developmental outcomes. This cohort will contribute to the understanding of the biologic mechanisms and social/environmental pathways underlying associations between early and later life outcomes, gene-environment interactions, and developmental trajectories among children.

Behavioral Science Research Informs Bioethical Issues in the Conduct of Large-Scale Studies of Children's Disease Risk

BACKGROUND

Birth cohort studies of the natural history of pediatric common disease risk raise many bioethical issues, including re-consenting participants over time as children mature and cohort retention. Understanding participants' study-specific knowledge, attitudes, beliefs, and behavior may offer insights into these issues from a psychological perspective.

METHODS

We conducted an analysis of factors associated with parent-child communication about minor children's participation in a population-based birth cohort; children's knowledge about their own participation; and parental willingness to be re-contacted for future study among Swedish parents (N = 3,605) of children originally enrolled at birth in a prospective study of type 1 diabetes risk.

RESULTS

More open parent-child communication about disease risk screening research and greater knowledge among children about their own research participation facilitated greater parent willingness to participate in further study. Parents' decisions about further study participation were most strongly favorable among those who communicated openly with their child and with high study-specific knowledge.

CONCLUSIONS

Epidemiologists, bioethicists, and others involved in the design and conduct of large-scale, prospective birth cohorts may consider embedding periodic assessments of participants' study-specific attitudes and behavior to address long-term retention and willingness to engage in future research.

Rationale and design of the PRegnancy and Infant DEvelopment (PRIDE) Study

BACKGROUND

To optimise the health of pregnant women and their children by evidence-based primary and secondary prevention, more scientific knowledge is needed. To overcome the methodological limitations of many studies on pregnancy and child health, which often use a retrospective design, we established the PRIDE (PRegnancy and Infant DEvelopment) Study.

METHODS AND RESULTS

The PRIDE Study is a large prospective cohort study that aims at including 150 000-200 000 women in early pregnancy to study a broad range of research questions pertaining to pregnancy complications, maternal and child health, and adverse developmental effects in offspring. Women are invited to participate by their prenatal care provider before or at their first prenatal care visit and are asked to fill out web-based questionnaires in gestational weeks 8-10, 17, and 34, as well as biannually throughout childhood. In addition, a food frequency questionnaire and a paternal questionnaire are administered and medical records are consulted. Multiple validation studies will be conducted and paper-and-pencil questionnaires are available for women who cannot or do not want to participate through the Internet. For subgroups of participants, blood and saliva samples for genetic and biochemical analyses are being collected. The pilot phase, which started in July 2011, showed a response rate of 47%. Recruitment will eventually cover all of the Netherlands.

CONCLUSIONS

We expect that this study, which will be the largest birth cohort in the world so far, will provide new insights in the aetiology of disorders and diseases that originate in pregnancy. The PRIDE Study is open for collaboration.

[Concept for a German national birth cohort for environmental health research]

The German Federal Environment Agency has commissioned the conceptual work for a birth cohort study to investigate environmental health problems in children. The recruitment is intended to start as early as possible in pregnancy and to take place in several regions of Germany. To detect health risks for exposures and outcomes with low prevalence as well as gene-environment interactions, a cohort size of 100,000-200,000 parent-child pairs is needed. The concept focuses on five health issues: neurodevelopment; reproductive development; pregnancy and birth outcomes; asthma, allergies and respiratory disease; obesity, insulin resistance and diabetes. The examination of additional health conditions will be possible. The exposure assessment will cover chemical, biological and physical exposures; psychosocial factors and genetics will be assessed as well. Biological and environmental samples will be stored in a repository for future analyses. The birth cohort study will contribute to the detection of associations between environmental exposures and health conditions over the course of life, which in turn will have an impact on environmental and health policies.

Maternal psychosocial determinants of fetal and infant health and the National Children's Study

The purpose of this article is to inform perinatal nurses about the longitudinal National Children's Study (NCS), which was mandated by Congress. The NCS was designed to follow infants from before birth to age 21, and researchers propose to study 100,000 children. This complex and extensive study will provide especially relevant information to perinatal nurses in practice, teaching, and research.

Advancing the science of environmental exposures during pregnancy and the gene-environment through the National Children's Study

In this article we provide nurses with information on the importance of studying environmental exposures during fetal, infant, and childhood development in the National Children's Study. Nurses should be aware of this study to aid in mitigating the complex health problems that arise from environment-health interactions. Nurses may help to educate the public, patients, and caregivers and are in an ideal position to be strong advocates for policy change and regulatory monitoring and enforcement.

Children's environmental health in agricultural settings

Children residing in rural settings may encounter environmental hazards derived from agricultural production activities. Health consequences of organic dusts, farm chemicals including pesticides, machinery noise, excess sun exposure, and zoonotic infectious agents have been clearly described among farm-working adults. The author reviews the related evidence base on child health with a life-stage perspective on their differential exposure and vulnerabilities. Methemoglobinemia among infants consuming nitrate-contaminated well water, neurodevelopmental health impacts associated with early life exposure to organophosphate pesticides, and diarrheal disease due to zoonotic infectious agents are well-described pediatric concerns. There is suggestive but more limited evidence for respiratory health consequences from air contaminants associated with confined animal feeding operations and hearing deficits for children exposed to machinery-related noise. Many contaminants of concern for children in these environments remain largely understudied-diesel exhaust, biomass burning, solvents, veterinary antibiotics, and silica-containing particulate matter. Overall, the state of knowledge and programmatic activities on agriculturally derived environmental contaminants and child health is immature and much less complete than for working adults. This overview provides a context for research, policy, and programmatic needs.

Birth defects in infants born in 1998-2004 to men and women serving in the U.S. military during the 1990-1991 Gulf War era

BACKGROUND

Concerns about reproductive health persist among U.S. military members who served in the 1990-1991 Gulf War. This study explores the long-term impact of 1990-1991 Gulf War deployment on the prevalence of birth defects among infants of Gulf War veterans.

METHODS

Health care data from the Department of Defense Birth and Infant Health Registry and demographic and deployment information from the Defense Manpower Data Center were used to identify infants born between 1998 and 2004 to both male and female 1990-1991 Gulf War veterans. Multivariable logistic regression models estimated the adjusted odds of any birth defect and eight specific birth defects among infants of deployers versus non-deployers. In addition, birth defects were evaluated among infants born to 1990-1991 Gulf War veterans with deployment-specific exposures.

RESULTS

Among 178,766 infants identified for these analyses, 3.4% were diagnosed with a birth defect in the first year of life. Compared to infants of non-deployers, infants of deployers were not at increased odds of being diagnosed with a birth defect, or any of eight specific birth defects, in the first year of life. A slightly increased prevalence of birth defects was observed among infants born to men who deployed to the 1990-1991 Gulf War for 153 to 200 days compared to those who deployed for 1 to 92 days. No other deployment-specific exposures were associated with birth defects in these infants.

CONCLUSIONS

The 1990-1991 Gulf War deployers, including those with specific exposures of concern, were not found to be at increased risk for having infants with birth defects 7 to 14 years after deployment.

Comparative effectiveness and child health

Comparative effectiveness research is expected to play an important role in future clinical and policy decision making in the US; however, the application of comparative effectiveness methodologies to child health requires special attention to aspects of health and healthcare that are specific to children. These special considerations include the role of parent/caregiver as joint decision maker and co-participant in many types of interventions, how the effectiveness of an intervention varies by age and developmental stage, and the difficulties in translating short-term data from childhood into projected effectiveness over the lifespan. Each aspect of comparative effectiveness, such as conducting new studies, synthesizing existing evidence, emphasizing real-world settings, considering multiple decision makers, and measuring patient-relevant outcomes, will require expanded definitions when considered in the context of child health. This paper discusses how comparative effectiveness methods and concepts will differ when applied to child health and suggests a potential role for decision analysis as a method to synthesize data and project long-term outcomes. The initiation of comparative effectiveness studies for children represents an exciting opportunity to provide evidence that can guide clinical and policy decisions for child health.

Autism spectrum disorders in the Stockholm Youth Cohort: design, prevalence and validity

OBJECTIVE

Reports of rising prevalence of autism spectrum disorders (ASD), along with their profound personal and societal burden, emphasize the need of methodologically sound studies to explore their causes and consequences. We here present the design of a large intergenerational resource for ASD research, along with population-based prevalence estimates of ASD and their diagnostic validity.

METHOD

The Stockholm Youth Cohort is a record-linkage study comprising all individuals aged 0-17 years, ever resident in Stockholm County in 2001-2007 (N = 589,114). ASD cases (N = 5,100) were identified using a multisource approach, involving registers covering all pathways to ASD diagnosis and care, and categorized according to co-morbid intellectual disability. Prospectively recorded information on potential determinants and consequences of ASD were retrieved from national and regional health and administrative registers. Case ascertainment was validated through case-note review, and cross validation with co-existing cases in a national twin study.

RESULTS

The 2007 year prevalence of ASD in all children and young people was 11.5 per 1,000 (95% confidence interval 11.2-11.8), with a co-morbid intellectual disability recorded in 42.6% (41.0-44.2) of cases. We found 96.0% (92.0-98.4) of reviewed case-notes being consistent with a diagnosis of ASD, and confirmed ASD in 85.2% (66.2-95.8) of affected twins.

CONCLUSIONS

Findings from this contemporary study accords with recently reported prevalence estimates from Western countries at around 1%, based on valid case ascertainment. The Stockholm Youth Cohort, in light of the availability of extensive information from Sweden's registers, constitutes an important resource for ASD research. On-going work, including collection of biological samples, will enrich the study further.

Long-term outcomes of early-onset wheeze and asthma

Evidence from longitudinal cohort studies demonstrates that wheezing that begins in early life and continues into the school years generally persists into adulthood. This persistent wheezing is associated with lung function deficits and airways hyperresponsiveness that appear to be established in the first few years of life. Allergic sensitization early in life, early-life infection with rhinovirus, or colonization with any of a number of bacteria have been associated with increased risk of persistent wheeze. Early life, whether in utero or in the first few years of life, presents a window of vulnerability during which airway injury results in persistent airways dysfunction. Available data further suggest that a second such window of vulnerability might be present in the preadolescent and adolescent years. Lung function growth patterns established by age 6 years generally continue into early adulthood to middle adulthood, typically leaving groups of subjects with wheezing that persists into or relapses during adulthood with a mean FEV(1) of about 10% of predicted value less than their peers who do not wheeze. Subgroups of patients with persistent asthma, however, can have progressive decreases in lung function and enter adulthood with even lower lung function. The concern exists that these deficits in lung function apparent in early adulthood might put subjects at risk for the later development of chronic obstructive pulmonary disease.

Use of community-level data in the National Children's Study to establish the representativeness of segment selection in the Queens Vanguard Site

BACKGROUND

The WHO Multiple Exposures Multiple Effects (MEME) framework identifies community contextual variables as central to the study of childhood health. Here we identify multiple domains of neighborhood context, and key variables describing the dimensions of these domains, for use in the National Children's Study (NCS) site in Queens. We test whether the neighborhoods selected for NCS recruitment, are representative of the whole of Queens County, and whether there is sufficient variability across neighborhoods for meaningful studies of contextual variables.

METHODS

Nine domains (demographic, socioeconomic, households, birth rated, transit, playground/greenspace, safety and social disorder, land use, and pollution sources) and 53 indicator measures of the domains were identified. Geographic information systems were used to create community-level indicators for US Census tracts containing the 18 study neighborhoods in Queens selected for recruitment, using US Census, New York City Vital Statistics, and other sources of community-level information. Mean and inter-quartile range values for each indicator were compared for Tracts in recruitment and non-recruitment neighborhoods in Queens.

RESULTS

Across the nine domains, except in a very few instances, the NCS segment-containing tracts (N=43) were not statistically different from those 597 populated tracts in Queens not containing portions of NCS segments; variability in most indicators was comparable in tracts containing and not containing segments.

CONCLUSIONS

In a diverse urban setting, the NCS segment selection process succeeded in identifying recruitment areas that are, as a whole, representative of Queens County, for a broad range of community-level variables.