Postpartum Obesity Is Associated With Increases in Child Adiposity in Midchildhood in a Cohort of Black and Dominican Youth.

Background: Obesity disproportionately affects marginalized and low-income populations. Birth parent obesity from the prenatal period and childhood has been associated with child obesity. It is unknown whether prenatal or postnatal birth parent obesity has differential effects on subsequent changes in adiposity and metabolic health in children. Objectives: We evaluated how birth parent obesity 7 y after delivery was associated with child body composition changes and cardiometabolic health in midchildhood and further assessed the influence of the perinatal and postpartum period on associations. Methods: Black and Dominican pregnant individuals were enrolled, and dyads (n = 319) were followed up at child age 7 and 9 y. Measures included, height, weight, waist circumference (WC), and percent body fat (BF%). Multiple linear regression was used to relate postpartum weight status with child outcomes accounting for attrition, and a series of secondary analyses were conducted with additional adjustment for perinatal weight status, gestational weight gain (GWG), and/or long-term weight retention to evaluate how these factors influenced associations. Results: Almost one-quarter (23%) of birth parents and 24.1% children were classified with obesity at child age 7 y, while at 9 y, 30% of children had obesity. Birth parent obesity at child age 7 y was associated with greater changes, from ages 7 to 9 y, in child BMI z-score (ß: 0.13; 95% CI: 0.02, 0.24) and BF% (ß: 1.15; 95% CI: 0.22, 2.09) but not obesity at age 9 y. All observed associations crossed the null after additional adjustment for prenatal factors. Conclusions: Birth parent obesity at 7-y postpartum is associated with greater gains in child BMI z-score and BF% in midchildhood. These associations diminish after accounting for prenatal size, suggesting a lasting impact of the perinatal environment and that interventions supporting families from the prenatal period through childhood are needed.

Validation of a Blood-Based Protein Biomarker Panel for a Risk Assessment of Lethal Lung Cancer in the Physicians' Health Study.

This study aimed to assess a four-marker protein panel (4MP)'s performance, including the precursor form of surfactant protein B, cancer antigen 125, carcinoembryonic antigen, and cytokeratin-19, for predicting lung cancer in a cohort enriched with never- and ever-smokers. Blinded pre-diagnostic plasma samples collected within 2 years prior to a lung cancer diagnosis from 25 cases and 100 sex-, age-, and smoking-matched controls were obtained from the Physicians' Health Study (PHS). The 4MP yielded AUC performance estimates of 0.76 (95% CI: 0.61-0.92) and 0.69 (95% CI: 0.56-0.82) for predicting lung cancer within one year and within two years of diagnosis, respectively. When stratifying into ever-smokers and never-smokers, the 4MP had respective AUCs of 0.77 (95% CI: 0.63-0.92) and 0.72 (95% CI: 0.17-1.00) for a 1-year risk of lung cancer. The AUCs of the 4MP for predicting metastatic lung cancer within one year and two years of the blood draw were 0.95 (95% CI: 0.87-1.00) and 0.78 (95% CI: 0.62-0.94), respectively. Our findings indicate that a blood-based biomarker panel may be useful in identifying ever- and never-smokers at high risk of a diagnosis of lung cancer within one-to-two years.

Rhinorrhea and watery eyes in infancy and risk of attention-deficit hyperactivity disorder in school-age children.

Increased parasympathetic nervous system (PNS) activity is associated with attention-deficit/hyperactivity disorder (ADHD) inattentive symptoms, but not hyperactive-impulsive symptoms, and may contribute to inattentive subtype etiology. Guided by prior work linking infant rhinorrhea and watery eyes without a cold (RWWC) to PNS dysregulation, we examined associations between infant RWWC and childhood ADHD symptoms in a longitudinal cohort of Black and Latinx children living in the context of economic disadvantage (N = 301 youth: 158 females, 143 males). Infant RWWC predicted higher inattentive (relative risk [RR] 2.16, p < .001) but not hyperactive-impulsive (RR 1.53, p = .065) ADHD symptoms (DuPaul scale), administered to caregivers at child age 8-14 years. Stratified analyses revealed that these associations were present in females but not males, who were three times more likely to have higher ADHD current total symptoms if they had infant RWWC than if they did not. Additionally, associations between RWWC and inattention symptoms were observed only in females. RWWC may thus serve as a novel risk marker of ADHD inattentive-type symptoms, especially for females.

Combined and sequential exposure to prenatal second hand smoke and postnatal maternal distress is associated with cingulo-opercular global efficiency and attention problems in school-age children.

BACKGROUND: Prenatal exposure to secondhand (environmental) tobacco smoke (SHS) is associated with adverse neurodevelopmental outcomes, including altered functional activation of cognitive control brain circuitry and increased attention problems in children. Exposure to SHS is more common among Black youth who are also disproportionately exposed to socioeconomic disadvantage and concomitant maternal distress. We examine the combined effects of exposure to prenatal SHS and postnatal maternal distress on the global efficiency (GE) of the brain's cingulo-opercular (CO) and fronto-parietal control (FP) networks in childhood, as well as associated attention problems. METHODS: Thirty-two children of non-smoking mothers followed in a prospective longitudinal birth cohort at the Columbia Center for Children's Environmental Health (CCCEH) completed magnetic resonance imaging (MRI) at ages 7-9 years old. GE scores were extracted from general connectivity data collected while children completed the Simon Spatial Incompatibility functional magnetic resonance imaging (fMRI) task. Prenatal SHS was measured using maternal urinary cotinine from the third trimester; postnatal maternal distress was assessed at child age 5 using the Psychiatric Epidemiology Research Interview (PERI-D). The Child Behavior Checklist (CBCL) measured Attention and Attention Deficit Hyperactivity Disorder (ADHD) problems at ages 7-9. Linear regressions examined the interaction between prenatal SHS and postnatal maternal distress on the GE of the CO or FP networks, as well as associations between exposure-related network alterations and attention problems. All models controlled for age, sex, maternal education at prenatal visit, race/ethnicity, global brain correlation, and mean head motion. RESULTS: The prenatal SHS by postnatal maternal distress interaction term associated with the GE of the CO network (ß = 0.673, Bu = 0.042, t(22) = 2.427, p = .024, D = 1.42, 95% CI [0.006, 0.079], but not the FP network (ß = 0.138, Bu = 0.006, t(22) = 0.434, p = .668, 95% CI [-0.022, 0.033]). Higher GE of the CO network was associated with more attention problems (ß = 0.472, Bu = 43.076, t(23) = 2.780, p = .011, D = 1.74, n = 31, 95% CI [11.024, 75.128], n = 31) and ADHD risk (ß = 0.436, Bu = 21.961, t(29) = 2.567, p = .018, D = 1.81, 95% CI [4.219, 39.703], n = 30). CONCLUSIONS: These preliminary findings suggest that sequential prenatal SHS exposure and postnatal maternal distress could alter the efficiency of the CO network and increase risk for downstream attention problems and ADHD. These findings are consistent with prior studies showing that prenatal SHS exposure is associated with altered function of brain regions that support cognitive control and with ADHD problems. Our model also identifies postnatal maternal distress as a significant moderator of this association. These data highlight the combined neurotoxic effects of exposure to prenatal SHS and postnatal maternal distress. Critically, such exposures are disproportionately distributed among youth from minoritized groups, pointing to potential pathways to known mental health disparities.

Trajectory analysis of rhinitis in a birth cohort from lower-income New York City neighborhoods.

BACKGROUND: Rhinitis is a prevalent, chronic nasal condition associated with asthma. However, its developmental trajectories remain poorly characterized. OBJECTIVE: We sought to describe the course of rhinitis from infancy to adolescence and the association between identified phenotypes, asthma-related symptoms, and physician-diagnosed asthma. METHODS: We collected rhinitis data from questionnaires repeated across 22 time points among 688 children from infancy to age 11 years and used latent class mixed modeling (LCMM) to identify phenotypes. Once children were between ages 5 and 12, a study physician determined asthma diagnosis. We collected information on the following asthma symptoms: any wheeze, exercise-induced wheeze, nighttime coughing, and emergency department visits. For each, we used LCMM to identify symptom phenotypes. Using logistic regression, we described the association between rhinitis phenotype and asthma diagnosis and each symptom overall and stratified by atopic predisposition and sex. RESULTS: LCMM identified 5 rhinitis trajectory groups: never/infrequent; transient; late onset, infrequent; late onset, frequent; and persistent. LCMM identified 2 trajectories for each symptom, classified as frequent and never/infrequent. Participants with persistent and late onset, frequent phenotypes were more likely to be diagnosed with asthma and to have the frequent phenotype for all symptoms (P < .01). We identified interaction between seroatopy and rhinitis phenotype for physician-diagnosed asthma (P = .04) and exercise-induced wheeze (P = .08). Severe seroatopy was more common among children with late onset, frequent and persistent rhinitis, with nearly 25% of these 2 groups exhibiting sensitivity to 4 or 5 of the 5 allergens tested. CONCLUSIONS: In this prospective, population-based birth cohort, persistent and late onset, frequent rhinitis phenotypes were associated with increased risk of asthma diagnosis and symptoms during adolescence.

Associations between mitochondrial biomarkers, urban residential exposures and childhood asthma outcomes over 6 months.

Determining biomarkers of responses to environmental exposures and evaluating whether they predict respiratory outcomes may help optimize environmental and medical approaches to childhood asthma. Relative mitochondrial (mt) DNA abundance and other potential mitochondrial indicators of oxidative stress may provide a sensitive metric of the child's shifting molecular responses to its changing environment. We leveraged two urban childhood cohorts (Environmental Control as Add-on Therapy in Childhood Asthma (ECATCh); Columbia Center for Children's Environmental Health (CCCEH)) to ascertain whether biomarkers in buccal mtDNA associate with airway inflammation and altered lung function over 6 months of time and capture biologic responses to multiple external stressors such as indoor allergens and fine particulate matter (PM2.5). Relative mtDNA content was amplified by qPCR and methylation of transfer RNA phenylalanine/rRNA 12S (TF/RNR1), cytochrome c oxidase (CO1), and carboxypeptidase O (CPO) was measured by pyrosequencing. Data on residential exposures and respiratory outcomes were harmonized between the two cohorts. Repeated measures and multiple regression models were utilized to assess relationships between mitochondrial biomarkers, respiratory outcomes, and residential exposures (PM2.5, allergens), adjusted for potential confounders and time-varying asthma. We found across the 6 month visits, a 0.64 fold higher level of TF/RNR1 methylation was detected among those with asthma in comparison to those without asthma ((parameter estimate (PE) 0.64, standard error 0.28, p = 0.03). In prospective analyses, CPO methylation was associated with subsequent reduced forced vital capacity (FVC; PE -0.03, standard error 0.01, p = 0.02). Bedroom dust mouse allergen, but not indoor PM2.5, was associated with higher methylation of TF/RNR1 (PE 0.015, standard error 0.006, p = 0.01). Select mtDNA measures in buccal cells may indicate children's responses to toxic environmental exposures and associate selectively with asthma and lung function.

Socioeconomic Status at Birth and Breast Tissue Composition in Adolescence and Adulthood.

BACKGROUND: Socioeconomic status (SES) at birth is associated with breast cancer risk. Whether this association is driven by changes in breast tissue composition (BTC) prior to adulthood remains unclear. METHODS: We used multivariable linear regression models to examine whether SES at birth is associated with BTC in adolescence and adulthood using data from a New York City cohort of daughters (n = 165, 11-20 years) and mothers (n = 160, 29-55 years). We used maternal-reported data on daughters' household income and maternal education at birth, analyzed individually and in combination (SES index). Women also reported their own mothers' education at birth. We used optical spectroscopy to evaluate BTC measures that positively (water content, collagen content, optical index) and negatively (lipid content) correlate with mammographic breast density, a recognized breast cancer risk factor. RESULTS: Being in the highest versus lowest category of the SES index was associated with lower lipid content [ßadjusted (ßadj) = -0.80; 95% confidence interval (CI), -1.30 to -0.31] and higher collagen content (ßadj = 0.54; 95% CI, 0.09-0.99) in adolescence. In women with a body mass index (BMI) <30 kg/m2, higher maternal education at birth (≥ vs. < high school degree) was associated with lower lipid content (ßadj = -0.57; 95% CI, -0.97 to -0.17), higher water content (ßadj = 0.70; 95% CI, 0.26-1.14), and higher optical index (ßadj = 0.53; 95% CI, 0.10-0.95). CONCLUSIONS: This study supports that SES at birth is associated with BTC in adolescence and adulthood, although the latter association may depend on adult BMI. IMPACT: Further research is needed to identify the socially patterned early life factors influencing BTC.

Characterizing changes in behaviors associated with chemical exposures during the COVID-19 pandemic.

The COVID-19 pandemic-and its associated restrictions-have changed many behaviors that can influence environmental exposures including chemicals found in commercial products, packaging and those resulting from pollution. The pandemic also constitutes a stressful life event, leading to symptoms of acute traumatic stress. Data indicate that the combination of environmental exposure and psychological stress jointly contribute to adverse child health outcomes. Within the Environmental influences on Child Health Outcomes (ECHO)-wide Cohort, a national consortium initiated to understand the effects of environmental exposures on child health and development, our objective was to assess whether there were pandemic-related changes in behavior that may be associated with environmental exposures. A total of 1535 participants from nine cohorts completed a survey via RedCap from December 2020 through May 2021. The questionnaire identified behavioral changes associated with the COVID-19 pandemic in expected directions, providing evidence of construct validity. Behavior changes reported by at least a quarter of the respondents include eating less fast food and using fewer ultra-processed foods, hair products, and cosmetics. At least a quarter of respondents reported eating more home cooked meals and using more antibacterial soaps, liquid soaps, hand sanitizers, antibacterial and bleach cleaners. Most frequent predictors of behavior change included Hispanic ethnicity and older age (35 years and older). Respondents experiencing greater COVID-related stress altered their behaviors more than those not reporting stress. These findings highlight that behavior change associated with the pandemic, and pandemic-related psychological stress often co-occur. Thus, prevention strategies and campaigns that limit environmental exposures, support stress reduction, and facilitate behavioral change may lead to the largest health benefits in the context of a pandemic. Analyzing biomarker data in these participants will be helpful to determine if behavior changes reported associate with measured changes in exposure.

Characteristics of peak exposure to black carbon pollution in school, commute and home environments among school children in an urban community.

Although real-time personal exposure monitoring devices have the ability to capture a wealth of data regarding fluctuations in pollutant levels, only a few studies have defined 'peaks' in black carbon (BC) exposure utilizing high-resolution data. Furthermore, studies to assess and characterize various features of peak exposure are very limited especially among children. A better understanding of characteristics of BC peak exposure would improve our understanding of health risks associated with BC. By capturing personal BC exposure at 5-min intervals using a real-time monitor during 24-hr monitoring periods among children in New York City (NYC), we defined 'peak characteristics' in 4 different ways across three major microenvironments (school vs. commute vs. home): 1) mean concentrations of BC across the 3 microenvironments, 2) 'peak duration' or time spent above the peak threshold (i.e., ≥1.5 µg/m3), 3) 'peak intensity' or the rate of exposure, defined as time spent above the threshold within each microenvironment divided by the total time spent in the microenvironment and 4) a novel metric of 'peak variability', defined as frequency of peaks (i.e., data points with +50% and -50% changes compared to the preceding and the subsequent data points), divided by the total time spent in the microenvironment. While peak duration was greatest at home, the intensity of peak exposure was greatest during commute hours, despite the short time spent in commute (p < 0.05). Peak variability was highest during commute, yet lowest in home environments (p < 0.05), particularly during non-sleeping hours. Children residing in a high-density urban setting spent on average, 5.4 hr per day above our peak threshold (≥1.5 µg/m3) in their everyday environments. Policies that limit children's exposure during high traffic periods and improved efforts to increase the number of vehicles using clean air technology could reduce the intensity of peaks and peak variability in children's BC exposure.

When a birth cohort grows up: challenges and opportunities in longitudinal developmental origins of health and disease (DOHaD) research.

High-quality evidence from prospective longitudinal studies in humans is essential to testing hypotheses related to the developmental origins of health and disease. In this paper, the authors draw upon their own experiences leading birth cohorts with longitudinal follow-up into adulthood to describe specific challenges and lessons learned. Challenges are substantial and grow over time. Long-term funding is essential for study operations and critical to retaining study staff, who develop relationships with participants and hold important institutional knowledge and technical skill sets. To maintain contact, we recommend that cohorts apply multiple strategies for tracking and obtain as much high-quality contact information as possible before the child's 18th birthday. To maximize engagement, we suggest that cohorts offer flexibility in visit timing, length, location, frequency, and type. Data collection may entail multiple modalities, even at a single collection timepoint, including measures that are self-reported, research-measured, and administrative with a mix of remote and in-person collection. Many topics highly relevant for adolescent and young adult health and well-being are considered to be private in nature, and their assessment requires sensitivity. To motivate ongoing participation, cohorts must work to understand participant barriers and motivators, share scientific findings, and provide appropriate compensation for participation. It is essential for cohorts to strive for broad representation including individuals from higher risk populations, not only among the participants but also the staff. Successful longitudinal follow-up of a study population ultimately requires flexibility, adaptability, appropriate incentives, and opportunities for feedback from participants.

Prenatal exposure to polybrominated diphenyl ethers and birth outcomes.

BACKGROUND: Polybrominated diphenyl ethers (PBDEs) were used as flame retardants and from their end-use products they can be released to accumulate within indoor environments. This may result in exposures to pregnant women with potential adverse effects on the developing fetus. While studies have shown associations between prenatal PBDE exposure and poor birth outcomes, research has mainly focused on birth weight and gestational age and may miss important indicators of newborn size. METHODS: The sample included a cohort of Dominican and African American mother-child pairs from New York City recruited from 1998 to 2006. PBDE congeners (BDE-47, BDE-99, BDE-100, and BDE-153) were measured in cord serum at birth and dichotomized into low (<80th percentile) and high (>80th percentile) categories. Weight, length, head circumference, and gestational age were measured at birth and the ponderal index (birth weight/length x 100), size for gestational age, and population-based z-scores were calculated (n = 305). Separate regression analyses were conducted to estimate associations between PBDEs or PBDE sum (ng/g lipid) and birth outcomes. Quantile g-computation was performed to estimate the effect of total PBDE mixture. We also assessed effect modification by sex and ethnicity. RESULTS: Adjusting for relevant covariates, the high exposure category of BDE-153 was associated with lower birth weight z-score (-0.25, 95% CI: -0.5, 0.0) and longer gestation (0.43 weeks, 95% CI: 0.07, 0.79). The high exposure category of BDE-99 was associated with lower birth length z-score (-0.55, 95% CI: -0.98, -0.12). There was a negative association between the overall PBDE mixture and birth length z-score (-0.10, 95% CI: -0.21, 0.00) per 1 quintile increase in PBDEs. There was no effect modification by sex or ethnicity. CONCLUSIONS: These results suggest that prenatal exposures to BDE-153, BDE-99, and total PBDE mixture are associated with birth outcomes in a cohort of Dominican and African American newborns.

Clean fleets, different streets: evaluating the effect of New York City's clean bus program on changes to estimated ambient air pollution.

BACKGROUND: Motor vehicles, including public transit buses, are a major source of air pollution in New York City (NYC) and worldwide. To address this problem, governments and transit agencies have implemented policies to introduce cleaner vehicles into transit fleets. Beginning in 2000, the Metropolitan Transit Agency began deploying compressed natural gas, hybrid electric, and low-sulfur diesel buses to reduce urban air pollution. OBJECTIVE: We hypothesized that bus fleet changes incorporating cleaner vehicles would have detectable effects on air pollution concentrations between 2009 and 2014, as measured by the New York City Community Air Survey (NYCCAS). METHODS: Depot- and route-specific information allowed identification of areas with larger or smaller changes in the proportion of distance traveled by clean buses. Data were assembled for 9670 300 m × 300 m grid cell areas with annual concentration estimates for nitrogen oxide (NO), nitrogen dioxide (NO2), and black carbon (BC) from NYCCAS. Spatial error models adjusted for truck route presence and total traffic volume. RESULTS: While concentrations of all three pollutants declined between 2009 and 2014 even in the 39.7% of cells without bus service, the decline in concentrations of NO and NO2 was greater in areas with more bus service and with higher proportional shifts toward clean buses. Conversely, the decline in BC concentration was slower in areas with more bus service and higher proportional clean bus shifts. SIGNIFICANCE: These results provide evidence that the NYC clean bus program impacted concentrations of air pollution, particularly in reductions of NO2. Further work can investigate the potential impact of these changes on health outcomes in NYC residents. IMPACT STATEMENT: Urban air pollution from diesel-burning buses is an important health exposure. The New York Metropolitan Transit Agency has worked to deploy cleaner buses into their fleet, but the impact of this policy has not been evaluated. Successful reductions in air pollution are critical for public health.

Assessment of the health benefits to children of a transportation climate policy in New York City.

BACKGROUND: Assessments of health and environmental effects of clean air and climate policies have revealed substantial health benefits due to reductions in air pollution, but have included few pediatric outcomes or assessed benefits at the neighborhood level. OBJECTIVES: We estimated benefits across a suite of child health outcomes in 42 New York City (NYC) neighborhoods under the proposed regional Transportation and Climate Initiative. We also estimated their distribution across racial/ethnic and socioeconomic groups. METHODS: We estimated changes in ambient fine particulate matter (PM2.5) and nitrogen dioxide (NO2) concentrations associated with on-road emissions under nine different predefined cap-and-invest scenarios. Health outcomes, including selected adverse birth, respiratory, and neurodevelopmental outcomes, were estimated using a program similar to the U.S. EPA BenMAP program. We stratified the associated monetized benefits across racial/ethnic and socioeconomic groups. RESULTS: The benefits varied widely over the different cap-and-investment scenarios. For a 25% reduction in carbon emissions from 2022 to 2032 and a strategy prioritizing public transit investments, NYC would have an estimated 48 fewer medical visits for childhood asthma, 13,000 avoided asthma exacerbations not requiring medical visits, 640 fewer respiratory illnesses unrelated to asthma, and 9 avoided adverse birth outcomes (infant mortality, preterm birth, and term low birth weight) annually, starting in 2032. The total estimated annual avoided costs are $22 million. City-wide, Black and Hispanic children would experience 1.7 times the health benefits per capita than White and Non-Hispanic White children, respectively. Under the same scenario, neighborhoods experiencing the highest poverty rates in NYC would experience about 2.5 times the health benefits per capita than the lowest poverty neighborhoods. CONCLUSION: A cap-and-invest strategy to reduce carbon emissions from the transportation sector could provide substantial health and monetized benefits to children in NYC through reductions in criteria pollutant concentrations, with greater benefits among Black and Hispanic children.

Exposure to polycyclic aromatic hydrocarbons during pregnancy and breast tissue composition in adolescent daughters and their mothers: a prospective cohort study.

BACKGROUND: Polycyclic aromatic hydrocarbons (PAH), which are found in air pollution, have carcinogenic and endocrine disrupting properties that might increase breast cancer risk. PAH exposure might be particularly detrimental during pregnancy, as this is a time when the breast tissue of both the mother and daughter is undergoing structural and functional changes. In this study, we tested the hypothesis that ambient PAH exposure during pregnancy is associated with breast tissue composition, measured one to two decades later, in adolescent daughters and their mothers. METHODS: We conducted a prospective analysis using data from a New York City cohort of non-Hispanic Black and Hispanic mother-daughter dyads (recruited 1998-2006). During the third trimester of pregnancy, women wore backpacks containing a continuously operating air sampling pump for two consecutive days that measured ambient exposure to eight carcinogenic higher molecular weight nonvolatile PAH compounds (Σ8 PAH) and pyrene. When daughters (n = 186) and mothers (n = 175) reached ages 11-20 and 29-55 years, respectively, optical spectroscopy (OS) was used to evaluate measures of breast tissue composition (BTC) that positively (water content, collagen content, optical index) and negatively (lipid content) correlate with mammographic breast density, a recognized risk factor for breast cancer. Multivariable linear regression was used to evaluate associations between ambient PAH exposure and BTC, overall and by exposure to household tobacco smoke during pregnancy (yes/no). Models were adjusted for race/ethnicity, age, and percent body fat at OS. RESULTS: No overall associations were found between ambient PAH exposure (Σ8 PAH or pyrene) and BTC, but statistically significant additive interactions between Σ8 PAH and household tobacco smoke exposure were identified for water content and optical index in both daughters and mothers (interaction p values < 0.05). Σ8 PAH exposure was associated with higher water content (ßdaughters = 0.42, 95% CI = 0.15-0.68; ßmothers = 0.32, 95% CI = 0.05-0.61) and higher optical index (ßdaughters = 0.38, 95% CI = 0.12-0.64; ßmothers = 0.38, 95% CI = 0.12-0.65) in those exposed to household tobacco smoke during pregnancy; no associations were found in non-smoking households (interaction p values < 0.05). CONCLUSIONS: Exposure to ambient Σ8 PAH and tobacco smoke during pregnancy might interact synergistically to impact BTC in mothers and daughters. If replicated in other cohorts, these findings might have important implications for breast cancer risk across generations.

Association Studies of Environmental Exposures, DNA Methylation and Children's Cognitive, Behavioral, and Mental Health Problems.

Introduction: Prenatal environmental exposures have been associated with children's cognitive, behavioral, and mental health problems, and alterations in DNA methylation have been hypothesized as an underlying biological mechanism. However, when testing this hypothesis, it is often difficult to overcome the problem of multiple comparisons in statistical testing when evaluating a large number of developmental outcomes and DNA methylation sites as potential mediators. The objective of this study is to implement a 'meet-in-the-middle' approach with a sequential roadmap to address this concern. Methods: In the Columbia Center for Children's Environmental Health birth cohort study, we implemented a 5-step sequential process for identifying CpG sites that mediate associations between prenatal environmental exposures and cognitive, behavioral, and mental health problems as measured by the Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV) and the Child Behavior Checklist (CBCL). These steps include 1) the identification of biological pathways that are relevant to each outcome of interest; 2) selection of a set of genes and CpGs on genes that are significantly associated with the outcomes; 3) identification of exposures that are significantly associated with selected CpGs; 4) examination of exposure-outcome relationships among those where significant CpGs were identified; and 5) mediation analysis of the selected exposures and corresponding outcomes. In this study, we considered a spectrum of environmental exposure classes including environmental phenols, pesticides, phthalates, flame retardants and air pollutants. Results: Among all considered exposures and outcomes, we found one CpG site (cg27510182) on gene (DAB1) that potentially mediates the effect of exposure to PAH on CBCL social problems at children aged 7. Conclusion: This 'meet-in-the-middle' approach attenuates concerns regarding multiple comparisons by focusing on genes and pathways that are biologically relevant for the hypothesis.

Correction: Racial and geographic variation in effects of maternal education and neighborhood-level measures of socioeconomic status on gestational age at birth: Findings from the ECHO cohorts.

[This corrects the article DOI: 10.1371/journal.pone.0245064.].