Search

BACKGROUND: Emerging studies suggest that ambient temperature during pregnancy may be associated with fetal growth, but the existing evidence is limited and inconsistent. OBJECTIVES: We aimed to evaluate the association of trimester-specific temperature with risk of being born small for gestational age (SGA) and birth weight-markers of fetal growth-among term births in the contiguous United States. METHODS: We included data on 29,597,735 live singleton births between 1989 and 2002 across 403 U.S. counties. We estimated daily county-level population-weighted mean temperature using a spatially refined gridded climate data set. We used logistic regression to estimate the association between trimester-specific temperature and risk of SGA and linear regression to evaluate the association between trimester-specific temperature and term birth weight z-score, adjusting for parity, maternal demographics, smoking or drinking during pregnancy, chronic hypertension, and year and month of conception. We then pooled results overall and by geographic regions and climate zones. RESULTS: High ambient temperatures (>90th percentile) during the entire pregnancy were associated with higher risk of term SGA {odds ratio [OR] = 1.041 [95% confidence interval (CI): 1.029, 1.054]} and lower term birth weight [standardized to -15 g (95% CI: -17 g, -13 g) reduction in birth weight for infants born at 40 weeks of gestation]. Low temperatures (≤10th percentile) during the entire pregnancy were not associated with SGA [OR = 1.003 (95% CI: 0.991, 1.015)] but were associated with a small decrement in term birth weight [standardized to -6 g (95% CI: -8 g, -4 g)]. Risks of term SGA and birth weight were more strongly associated with temperature averaged across the second and third trimesters, in areas the Northeast, and in areas with cold or very cold climates. CONCLUSIONS: Above-average temperatures during pregnancy were associated with lower fetal growth. Our findings provide evidence that temperature may be a novel risk factor for reduced fetal growth. [ABSTRACT FROM AUTHOR]

Environmental exposures contribute to multiple diseases in children; yet, few pediatricians have training in pediatric environmental health (PEH), and few academic health centers have PEH expertise. To build national capacity in PEH, the Academic Pediatric Association (APA) launched a professional development program that since 2002 has encouraged the establishment of post-residency/post-doctoral training programs, supported a special interest group, and convened an annual mentored retreat for PEH trainees. Describe the APA's professional development program in PEH and assess its impact by tracking careers of former trainees. Careers were tracked through interviews with trainees and program directors supplemented by searches of institutional websites. Publication listings were obtained through PubMed. Publication impact was assessed using bibliometric and altmetric measures. Grant histories were accessed through the National Institutes of Health RePORTER project. Information on advocacy work was obtained through interviews with program directors. Fifty-five trainees (36 physicians and 19 health scientists) completed PEH training and attended the APA retreat between 2002 and 2017. Forty-one (75%) are pursuing academic careers, 11 are associate or full professors, 11 are practicing general pediatrics or a pediatric subspecialty, 2 are Centers for Disease Control and Prevention epidemiologists, and 1 is a data scientist. Forty-two former trainees (76%) listed "environment" or "environmental" in their job titles or on their websites. Former trainees have published 632 scientific papers. These papers have been cited 3094times, have a relative citation ratio of 2.97, and have been read or viewed 1,274,388times. Twenty-one former trainees have been awarded 43 National Institutes of Health grants. Trainees have developed education and advocacy skills by teaching medical students and residents, presenting grand rounds, preparing policy papers, presenting legislative testimony, and making presentations to public audiences. The APA's professional development program has contributed to the expansion of national capacity in PEH. Former trainees are populating the field, generating new knowledge, and moving into leadership positions. [ABSTRACT FROM AUTHOR]

Perfluoroalkyl substances (PFAS) are persistent endocrine disrupting chemicals found in industrial and commercial products. Previous research has shown that other endocrine disrupting chemicals such as phthalates and bisphenol A may alter circulating levels of vitamin D; however, no research has examined associations between PFAS and vitamin D biomarkers. We conducted a cross-sectional analysis of 7040 individuals aged 12 years and older participating in the 2003-2010 cycles of the United States National Health and Nutrition Examination Survey (NHANES). Concentrations of perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA), and total 25-hydroxyvitamin D [25(OH)D] were measured in serum samples. We used multivariable linear regression to estimate covariate-adjusted differences in total 25(OH)D or prevalence odds of vitamin D deficiency per log2 change in PFAS concentrations. We also assessed potential effect measure modification by gender, age, and race/ethnicity. PFAS were detected in over 98% of the samples. In adjusted models, each 2-fold increase in PFOS was associated with 0.9 nmol/L (95% CI: 0.2, 1.5) lower total 25(OH)D concentrations, with associations significantly stronger among whites (β: -1.7; 95% CI: -2.6, -0.7) and individuals older than 60 years of age (β: -1.7; 95% CI: -2.9, -0.5). Each 2-fold increase in PFHxS was associated with 0.8 nmol/L (95% CI: 0.3, 1.3) higher total 25(OH)D, and this association was not modified by age, gender, and race/ethnicity. PFOA and PFNA were not associated with total 25(OH)D. When assessing prevalence odds of vitamin D deficiency, we observed similar patterns of association with PFAS concentrations. Our results suggest that some PFAS may be associated with altered vitamin D levels in the United States population, and associations may vary by chemical, age, and race/ethnicity. Prospective epidemiological studies are needed to confirm our findings and determine their implications for vitamin D-associated health outcomes in children and adults. [ABSTRACT FROM AUTHOR]

Improving indoor air quality is one potential strategy to reduce the transmission of SARS-CoV-2 in any setting, including nursing homes, where staff and residents have been disproportionately and negatively affected by the COVID-19 pandemic. Single group interrupted time series. A total of 81 nursing homes in a multifacility corporation in Florida, Georgia, North Carolina, and South Carolina that installed ultraviolet air purification in their existing heating, ventilation, and air conditioning systems between July 27, 2020,k and September 10, 2020. We linked data on the date ultraviolet air purification systems were installed with the Nursing Home COVID-19 Public Health File (weekly data reported by nursing homes on the number of residents with COVID-19 and COVID-19 deaths), public data on data on nursing home characteristics, county-level COVID-19 cases/deaths, and outside air temperature. We used an interrupted time series design and ordinary least squares regression to compare trends in weekly COVID-19 cases and deaths before and after installation of ultraviolet air purification systems. We controlled for county-level COVID-19 cases, death, and heat index. Compared with pre-installation, weekly COVID-19 cases per 1000 residents (−1.69; 95% CI, −4.32 to 0.95) and the weekly probability of reporting any COVID-19 case (−0.02; 95% CI, −0.04 to 0.00) declined in the post-installation period. We did not find any difference pre- and post-installation in COVID-19–related mortality (0.00; 95% CI, −0.01 to 0.02). Our findings from this small number of nursing homes in the southern United States demonstrate the potential benefits of air purification in nursing homes on COVID-19 outcomes. Intervening on air quality may have a wide impact without placing significant burden on individuals to modify their behavior. We recommend a stronger, experimental design to estimate the causal effect of installing air purification devices on improving COVID-19 outcomes in nursing homes. [ABSTRACT FROM AUTHOR]

Background Bisphenol A (BPA) has been linked to changes in the dopamine system and development of an Attention-Deficit/Hyperactivity Disorder (ADHD) phenotype in animal models, with differing effects in males compared to females. We examined the association between urinary BPA concentrations and ADHD in a national sample of U.S. children, and whether this association differs by child sex. Methods We used data from the 2003–2004 National Health and Nutrition Examination Survey, a cross-sectional, nationally representative sample of the U.S. population. Participants were 8-15 years of age (N=460). Using a diagnostic interview to ascertain the presence of ADHD in the past year, multivariable logistic regression examined the link between concurrent urinary BPA concentrations and ADHD status. Results Of the 460 participants, 7.1% [95% CI: 4.4–11.3] met Diagnostic and Statistical Manual of Mental Disorders – Fourth Edition (DSM-IV) criteria for ADHD. Children who had BPA concentrations at or above the median of the sample had higher prevalence of meeting criteria for ADHD (11.2% [95% CI: 6.8–17.8]) than those with BPA concentrations below the median (2.9% [95% CI: 1.1–7.2]). Higher urinary BPA concentrations were associated with ADHD (adjusted odds ratio [aOR]: 5.68 [95% CI: 1.6–19.8] for BPA concentrations above vs. below the median). In sex-stratified analyses, these associations were stronger in boys (aOR=10.9 [95% CI: 1.4–86.0]) than in girls (aOR=2.8 [95% CI: 0.4–21.3]), although the BPA by sex interaction term was not significant (p=0.25). Conclusion We found evidence that higher urinary BPA concentrations were associated with ADHD in U.S. children; these associations were stronger in boys than in girls. Considering the widespread use of BPA and growing literature on neurobehavioral effects of BPA in children, further study is warranted to determine if reducing exposure to BPA may represent an important avenue for ADHD prevention. [ABSTRACT FROM AUTHOR]

Abstract Background Days of extreme temperature may be associated with transiently higher risk of preterm birth, but prior studies have been limited and results have been heterogeneous. Objectives To evaluate the association between days of extreme heat and cold and risk of preterm birth among ~32 million live singleton births between 1989 and 2002 across 403 counties in the contiguous United States (US). Methods We used a distributed lag nonlinear model to estimate the association between population-weighted daily mean temperature and risk of preterm birth in each county and then pooled results across geographic regions and climate zones. We defined extreme heat and cold as the 95th and 5th percentile of the county-specific temperatures, respectively. Results Preterm birth accounted for 9.3% of deliveries. There was a monotonic association between ambient temperature and risk of preterm birth. Days of extreme heat and cold were associated with a relative risk of preterm birth of 1.025 (95% CI: 1.015, 1.036) and 0.985 (95% CI: 0.976, 0.993) over the subsequent four days, respectively, relative to the county-specific median temperature. If causal, the fraction of preterm births attributable to extreme heat was 0.17% (empirical 95% CI: 0.14%, 0.19%), corresponding to 154 (empirical 95% CI: 127, 173) preterm births per million births. Extreme heat was more strongly associated with preterm birth in regions with colder and drier climates, and among younger women. Days of extreme cold temperature were associated with lower rather than higher risk of preterm birth. Conclusions Days of extreme heat, but not extreme cold, are associated with higher risk of preterm birth in the contiguous US. If causal, these results may have important implications for the management of pregnant women during forecasted periods of extreme heat. Highlights • We examined the association between extreme temperature and PTB in the contiguous US. • Days of extreme heat were associated with higher risk of preterm birth. • The association was stronger in regions with typically colder and drier climates. [ABSTRACT FROM AUTHOR]

Objective: To determine if firearm ownership is positively related to elevated child lead levels at a state-level, even when accounting for other sources of lead., Study Design: For this cross-sectional ecological study, we investigated whether household firearm ownership rates (a proxy for firearm-related lead exposure) was associated with the prevalence of elevated child blood lead levels in 44 US States between 2012 and 2018. To account for potential confounding, we adjusted for other known lead exposures, poverty rate, population density, race, and calendar year. To address missing data, we used multiple imputation by chained equations., Results: Prevalence of elevated child blood lead positively correlated with household firearm ownership and established predictors of lead exposure. In fully adjusted negative binomial regression models, child blood lead was positively associated with household firearm ownership and older housing; each IQR (14%) increase in household firearm ownership rate was associated with a 41% higher prevalence of childhood elevated blood lead (prevalence ratio: 1.41, 95% CI: 1.11-1.79)., Conclusion: These data provide state-level evidence that firearms may be an important source of child lead exposure. More research is needed to substantiate this relationship and identify modifiable pathways of exposure at the individual level., Competing Interests: Declaration of Competing Interest JMB has been compensated for serving as an expert witness for plaintiffs involved in PFAS-contaminated drinking water and has NIH funding: R21 ES034187. MR has grants from the CDC and NIH related to firearm injury, and has unpaid roles as Senior Strategic Advisor to AFFIRM at the Aspen Institute and as a Board Member for the NonViolence Institute. The other authors have no conflicts of interest to disclose., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Quantifying a person's cumulative exposure burden to per- and polyfluoroalkyl substances (PFAS) mixtures is important for risk assessment, biomonitoring, and reporting of results to participants. However, different people may be exposed to different sets of PFASs due to heterogeneity in the exposure sources and patterns. Applying a single measurement model for the entire population (e.g., by summing concentrations of all PFAS analytes) assumes that each PFAS analyte is equally informative to PFAS exposure burden for all individuals. This assumption may not hold if PFAS exposure sources systematically differ within the population. However, the sociodemographic, dietary, and behavioral characteristics that underlie systematic exposure differences may not be known, or may be due to a combination of these factors. Therefore, we used mixture item response theory, an unsupervised psychometrics and data science method, to develop a customized PFAS exposure burden scoring algorithm. This scoring algorithm ensures that PFAS burden scores can be equitably compared across population subgroups. We applied our methods to PFAS biomonitoring data from the United States National Health and Nutrition Examination Survey (2013-2018). Using mixture item response theory, we found that participants with higher household incomes had higher PFAS burden scores. Asian Americans had significantly higher PFAS burden compared with non-Hispanic Whites and other race/ethnicity groups. However, some disparities were masked when using summed PFAS concentrations as the exposure metric. This work demonstrates that our summary PFAS burden metric, accounting for sources of exposure variation, may be a more fair and informative estimate of PFAS exposure.

Background: The United States Environmental Protection Agency (EPA) recently lowered residential floor and windowsill dust lead hazard standards, but maintained previous post-abatement clearance standards. We examined whether the discrepancy in these regulations places children at higher risk of lead poisoning., Methods: In 250 children from Cincinnati, Ohio (2004-2008) living in homes built before 1978, we measured residential floor and windowsill dust lead loadings and blood lead concentrations at ages 1 and 2 years. Using linear regression with generalized estimating equations, we estimated covariate-adjusted associations of dust lead levels with blood lead concentrations and risk of lead poisoning., Results: An increase in floor dust lead from 10 (revised dust lead hazard standard) to 40 μg/ft 2 (post-abatement clearance standard) was associated with 26% higher (95% confidence interval (CI):15, 38) blood lead concentrations and 2.1 times the risk of blood lead concentrations ≥5 μg/dL (95% CI: 1.44, 3.06). Extrapolating our findings to US children age 1-5 years, we estimated that 6.9% (95% CI: 1.5, 17.2) of cases of blood lead concentrations ≥5 μg/dL are attributable to floor dust lead loadings between 10 and ≤40 μg/ft 2 ., Conclusions: The EPA's residential dust lead regulations place children at increased risk of lead poisoning. We recommend adopting more protective dust lead standards., Impact: We determined whether children are at increased risk of lead poisoning with the 2019 EPA residential post-abatement lead clearance standards being higher than dust lead hazard standards. In this observational study, 2019 EPA dust lead clearance standards were associated with increased risk of lead poisoning compared to the revised dust lead hazard standard. Both EPA standards were associated with increased risk of lead poisoning compared to more stringent standards employed in our study. Extrapolating our findings to US children, the 2019 EPA dust lead clearance standards could place up to 36,700 children at risk of lead poisoning., (© 2020. International Pediatric Research Foundation, Inc.)

We examined the association between prenatal fish intake and child autism-related traits according to Social Responsiveness Scale (SRS) and cognitive development scores in two US prospective pregnancy cohorts. In adjusted linear regression analyses, higher maternal fish intake in the second half of pregnancy was associated with increased child autism traits (higher raw SRS scores; ß = 5.60, 95%CI 1.76, 12.97). Differences by fish type were suggested; shellfish and large fish species were associated with increases, and salmon with decreases, in child SRS scores. Clear patterns with cognitive scores in the two cohorts were not observed. Future work should further evaluate potential critical windows of prenatal fish intake, and the role of different fish types in association with child autism-related outcomes.

Background: Emerging studies suggest that ambient temperature during pregnancy may be associated with fetal growth, but the existing evidence is limited and inconsistent., Objectives: We aimed to evaluate the association of trimester-specific temperature with risk of being born small for gestational age (SGA) and birth weight-markers of fetal growth-among term births in the contiguous United States., Methods: We included data on 29,597,735 live singleton births between 1989 and 2002 across 403 U.S. counties. We estimated daily county-level population-weighted mean temperature using a spatially refined gridded climate data set. We used logistic regression to estimate the association between trimester-specific temperature and risk of SGA and linear regression to evaluate the association between trimester-specific temperature and term birth weight z-score, adjusting for parity, maternal demographics, smoking or drinking during pregnancy, chronic hypertension, and year and month of conception. We then pooled results overall and by geographic regions and climate zones., Results: High ambient temperatures ([Formula: see text] percentile) during the entire pregnancy were associated with higher risk of term SGA {odds ratio [OR] [Formula: see text] 1.041 [95% confidence interval (CI): 1.029, 1.054]} and lower term birth weight [standardized to [Formula: see text] (95% CI: [Formula: see text], [Formula: see text]) reduction in birth weight for infants born at 40 weeks of gestation]. Low temperatures ([Formula: see text] percentile) during the entire pregnancy were not associated with SGA [OR [Formula: see text] 1.003 (95% CI: 0.991, 1.015)] but were associated with a small decrement in term birth weight [standardized to [Formula: see text] (95% CI: [Formula: see text], [Formula: see text])]. Risks of term SGA and birth weight were more strongly associated with temperature averaged across the second and third trimesters, in areas the Northeast, and in areas with cold or very cold climates., Conclusions: Above-average temperatures during pregnancy were associated with lower fetal growth. Our findings provide evidence that temperature may be a novel risk factor for reduced fetal growth. https://doi.org/10.1289/EHP4648.

Study Objectives: Perfluoroalkyl acids (PFAAs) are a class of anthropogenic and persistent compounds that may impact some biological pathways related to oral health. The objective of our study was to estimate the relationship between dental caries prevalence and exposure to four PFAA: perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorohexane sulfonic acid (PFHxS) and perfluorooctane sulfonic acid (PFOS) in a nationally representative sample of US adolescents., Setting/design: We analysed cross-sectional data from the National Health and Nutrition Examination Survey from 1999 to 2012 for 12-19-year-old US adolescents., Participants: Of 10 856 adolescents aged 12 to 19 years who had a dental examination, we included 2869 with laboratory measurements for serum PFAA concentrations and complete covariate data in our study., Primary and Secondary Outcome Measures: Dental caries prevalence was defined as the presence of decay or a restoration on any tooth surface, or the loss of a tooth due to tooth decay. We used multivariable logistic regression to estimate the covariate-adjusted association between serum PFAA concentrations and dental caries prevalence, accounting for the complex National Health and Nutrition Examination Survey design., Results: Of 2869 adolescents, 59% had one or more dental caries. We observed no associations between the prevalence of dental caries and serum concentrations of PFOA, PFOS or PFHxS. The adjusted odds of caries were 21% (OR 0.79; 95% CI 0.63 to 1.01), 15% (OR 0.85; 95% CI 0.67 to 1.08) and 30% (OR 0.7; 95% CI 0.55 to 0.90) lower among adolescents in the 2nd, 3rd and 4th serum PFNA concentration quartiles compared to adolescents in the first quartile, respectively. The linear trend for this association was not statistically significant., Conclusion: PFOA, PFOS and PFHxS were not associated with prevalence of dental caries. The prevalence of caries was reduced with increasing serum PFNA concentrations; however, these results should be interpreted cautiously given that we were unable to adjust for several factors related to oral health., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Importance: Childhood lead exposure is associated with neurobehavioral deficits. The effect of a residential lead hazard intervention on blood lead concentrations and neurobehavioral development remains unknown., Objective: To determine whether a comprehensive residential lead-exposure reduction intervention completed during pregnancy could decrease residential dust lead loadings, prevent elevated blood lead concentrations, and improve childhood neurobehavioral outcomes., Design, Setting, and Participants: This longitudinal, community-based randomized clinical trial of pregnant women and their children, the Health Outcomes and Measures of the Environment (HOME) Study, was conducted between March 1, 2003, and January 31, 2006. Pregnant women attending 1 of 9 prenatal care clinics affiliated with 3 hospitals in the Cincinnati, Ohio, metropolitan area were recruited. Of the 1263 eligible women, 468 (37.0%) agreed to participate and 355 women (75.8%) were randomized in this intention-to-treat analysis. Participants were randomly assigned to receive 1 of 2 interventions designed to reduce residential lead or injury hazards. Follow-up on children took place at 1, 2, 3, 4, 5, and 8 years of age. Data analysis was performed from September 2, 2017, to May 6, 2018., Main Outcomes and Measures: Residential dust lead loadings were measured at baseline and when children were 1 and 2 years of age. At 1, 2, 3, 4, 5, and 8 years of age, the children's blood lead concentrations as well as behavior, cognition, and executive functions were assessed., Results: Of the 355 women randomized, 174 (49.0%) were assigned to the intervention group (mean [SD] age at delivery, 30.1 (5.5) years; 119 [68.3%] self-identified as non-Hispanic white) and 181 (50.9%) to the control group (mean [SD] age at delivery, 29.2 [5.7] years; 123 [67.9%] self-identified as non-Hispanic white). The intervention reduced the dust lead loadings for the floor (24%; 95% CI, -43% to 1%), windowsill (40%; 95% CI, -60% to -11%), and window trough (47%; 95% CI, -68% to -10%) surfaces. The intervention did not statistically significantly reduce childhood blood lead concentrations (-6%; 95% CI, -17% to 6%; P = .29). Neurobehavioral test scores were not statistically different between children in the intervention group than those in the control group except for a reduction in anxiety scores in the intervention group (β = -1.6; 95% CI, -3.2 to -0.1; P = .04)., Conclusions and Relevance: Residential lead exposures, as well as blood lead concentrations in non-Hispanic black children, were reduced through a comprehensive lead-hazard intervention without elevating the lead body burden. However, this decrease did not result in substantive neurobehavioral improvements in children., Trial Registration: ClinicalTrials.gov identifier: NCT00129324.

Triclosan and parabens are chemicals used in personal care and medical products as microbicides and preservatives. Triclosan and paraben exposure may be associated with allergy (atopy), but these associations have not been evaluated with respect to other atopic states such as eczema (atopic dermatitis). This study examines the associations of urinary triclosan and paraben concentrations with allergic sensitization and asthma in children according to eczema history. We performed a cross-sectional analysis of U.S. children aged 6-18 years who participated in the National Health and Nutrition Examination Survey (2005-2006). Triclosan and paraben concentrations were measured in urine. We assessed associations of triclosan and parabens with allergic sensitization and asthma using multivariable logistic regression in 837 children with complete data and stratified our results by eczema status. After covariate adjustment, triclosan and methyl and propyl paraben concentrations were positively associated with the odds of aeroallergen sensitization. Eczema did not significantly modify the association between triclosan or paraben levels and aeroallergen sensitization, asthma, or wheeze. The odds of parent-reported atopic asthma increased 34% (95% CI, 0, 81) across triclosan concentration quartiles. Increasing triclosan concentrations (quartiles) were associated with 2.3 times the odds of food sensitization (95% CI, 1.14, 4.44) among children with eczema, but not among children without eczema (OR, 1.25; 95% CI 0.93, 1.68; effect measure modification, p = 0.04). Triclosan and paraben exposures may increase the risk of atopic asthma and aeroallergen sensitization. Prospective studies are necessary to confirm these findings and determine if these chemicals pose a risk to children's health.

Objective: The purpose of this study was to examine the association of tobacco smoke and environmental lead exposure with conduct disorder (CD)., Methods: The National Health and Nutrition Examination Survey (NHANES) 2001-2004 is a nationally representative cross-sectional sample of the noninstitutionalized U.S. population. We examined the association of prenatal tobacco, postnatal tobacco, and environmental lead exposure with CD in children 8-15 years of age (n = 3,081). We measured prenatal tobacco exposure by parent report of cigarette use during pregnancy, and postnatal tobacco using serum cotinine levels. We assessed lead exposure using current blood lead concentration. Parents completed the Diagnostic Interview Schedule for Children to determine whether their children met criteria of the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV ) for CD., Results: Overall, 2.06% of children met DSM-IV criteria for CD in the past year, equivalent to 560,000 U.S. children 8-15 years of age. After adjustment, prenatal tobacco exposure was associated with increased odds for CD [odds ratio (OR) = 3.00; 95% confidence interval (CI), 1.36-6.63]. Increased blood lead levels (fourth vs. first quartile) and serum cotinine levels (fifth vs. first quintile) were associated with an 8.64-fold (95% CI, 1.87-40.04) and 9.15-fold (95% CI, 1.47-6.90) increased odds of meeting DSM-IV CD criteria. Increasing serum cotinine levels and blood lead levels were also associated with increased prevalence of CD symptoms (symptom count ratio, lead: 1.73; 95% CI, 1.23-2.43; symptom count ratio, cotinine: 1.97; 95% CI, 1.15-3.40)., Conclusions: These results suggest that prenatal tobacco exposure and environmental lead exposure contribute substantially to CD in U.S. children.