Faculty Bibliography

PURPOSE OF REVIEW/OBJECTIVE:To assess the strength of evidence for associations between environmental toxicants and hypertensive disorders of pregnancy, suggest potential biological mechanisms based on animal and in vitro studies, and highlight avenues for future research. RECENT FINDINGS/RESULTS:Evidence is strongest for links between persistent chemicals, including lead, cadmium, organochlorine pesticides, and polycyclic biphenyls, and preeclampsia, although associations are sometimes not detectable at low-exposure levels. Results have been inconclusive for bisphenols, phthalates, and organophosphates. Biological pathways may include oxidative stress, epigenetic changes, endocrine disruption, and abnormal placental vascularization. Additional prospective epidemiologic studies beginning in the preconception period and extending postpartum are needed to assess the life course trajectory of environmental exposures and women's reproductive and cardiovascular health. Future studies should also consider interactions between chemicals and consider nonlinear associations. These results confirm recommendations by the International Federation of Gynecology and Obstetrics, the American Society for Reproductive Medicine, the American Academy of Pediatrics, and the Endocrine Society that providers counsel their pregnant patients to limit exposure to environmental toxicants.

Our purposes with this policy statement and its accompanying technical report are to review and highlight emerging child health concerns related to the use of colorings, flavorings, and chemicals deliberately added to food during processing (direct food additives) as well as substances in food contact materials, including adhesives, dyes, coatings, paper, paperboard, plastic, and other polymers, which may contaminate food as part of packaging or manufacturing equipment (indirect food additives); to make reasonable recommendations that the pediatrician might be able to adopt into the guidance provided during pediatric visits; and to propose urgently needed reforms to the current regulatory process at the US Food and Drug Administration (FDA) for food additives. Concern regarding food additives has increased in the past 2 decades, in part because of studies in which authors document endocrine disruption and other adverse health effects. In some cases, exposure to these chemicals is disproportionate among minority and low-income populations. Regulation and oversight of many food additives is inadequate because of several key problems in the Federal Food, Drug, and Cosmetic Act. Current requirements for a "generally recognized as safe" (GRAS) designation are insufficient to ensure the safety of food additives and do not contain sufficient protections against conflict of interest. Additionally, the FDA does not have adequate authority to acquire data on chemicals on the market or reassess their safety for human health. These are critical weaknesses in the current regulatory system for food additives. Data about health effects of food additives on infants and children are limited or missing; however, in general, infants and children are more vulnerable to chemical exposures. Substantial improvements to the food additives regulatory system are urgently needed, including greatly strengthening or replacing the "generally recognized as safe" (GRAS) determination process, updating the scientific foundation of the FDA's safety assessment program, retesting all previously approved chemicals, and labeling direct additives with limited or no toxicity data.

BACKGROUND AND OBJECTIVE: In utero exposure to perfluorooctanoic acid (PFOA) has been associated with decreases in birth weight. We aimed to estimate the proportion of PFOA-attributable low birth weight (LBW) births and associated costs in the US from 2003 to 2014, a period during which there were industry-initiated and regulatory activities aimed at reducing exposure. METHODS: Serum PFOA levels among women 18-49 years were obtained from the National Health and Nutrition Examination Survey (NHANES) for 2003-2014; birth weight distributions were obtained from the Vital Statistics Natality Birth Data. The exposure-response relationship identified in a previous meta-analysis (18.9g decrease in birth weight per 1ng/mL of PFOA) was applied to quantify PFOA-attributable LBW (reference level of 3.1ng/mL for our base case, 1 and 3.9ng/mL for sensitivity analyses). Hospitalization costs and lost economic productivity were also estimated. RESULTS: Serum PFOA levels remained approximately constant from 2003-2004 (median: 3.3ng/mL) to 2007-2008 (3.5ng/mL), and declined from 2009-2010 (2.8ng/mL) to 2013-2014 (1.6ng/mL). In 2003-2004, an estimated 12,764 LBW cases (4% of total for those years) were potentially preventable if PFOA exposure were reduced to the base case reference level (10,203 cases in 2009-2010 and 1,491 in 2013-2014). The total cost of PFOA-attributable LBW for 2003 through 2014 was estimated at $13.7 billion, with $2.97 billion in 2003-2004, $2.4 billion in 2009-2010 and $347 million in 2013-2014. CONCLUSIONS: Serum PFOA levels began to decline in women of childbearing age in 2009-2010. Declines were of a magnitude expected to meaningfully reduce the estimated incidence of PFOA-attributable LBW and associated costs.

BACKGROUND:Exposure to bisphenols and phthalates in pregnancy may lead to adverse health effects in women themselves and their offspring. OBJECTIVE:To describe first trimester bisphenol and phthalate urine concentrations, including bisphenol and phthalate replacements, and determine nutritional, socio-demographic and lifestyle related determinants. METHODS:In a population-based prospective cohort of 1396 mothers, we measured first trimester bisphenol, phthalate and creatinine urine concentrations (samples collected in 2004-2005, median gestational age 12.9 weeks [inter-quartile range (IQR) 12.1-14.4]). We examined associations of potential determinants with log-transformed bisphenol and phthalate concentrations. Outcomes were back-transformed. Nutritional analyses were performed in a subgroup of 642 Dutch participants only, as the Food Frequency Questionnaire was aimed at Dutch food patterns. RESULTS:Bisphenol A, bisphenol S, and bisphenol F were detected in 79.2%, 67.8% and 40.2% of the population, respectively. Mono-n-butylphthalate, mono-(2-ethyl-5-hydroxyhexyl)phthalate and monobenzylphthalate were detected in > 90% of the population. Nutritional intake was not associated with bisphenol and phthalate concentrations after correction for multiple testing was applied. Obesity was associated with higher high-molecular-weight phthalate concentrations and the lack of folic acid supplement use with higher di-n-octylphthalate concentrations (respective mean differences were 46.73nmol/l [95% CI 14.56-93.72] and 1.03nmol/l [0.31-2.06]). CONCLUSION/CONCLUSIONS:Bisphenol S and F exposure was highly prevalent in pregnant women in the Netherlands as early as 2004-5. Although associations of dietary and other key factors with bisphenol and phthalate concentrations were limited, adverse lifestyle factors including obesity and the lack of folic acid supplement use seem to be associated with higher phthalate concentrations in pregnant women. The major limitation was the availability of only one urine sample per participant. However, since phthalates are reported to be quite stable over time, results concerning determinants of phthalate concentrations are expected to be robust.

BACKGROUND:The collapse of the World Trade Center (WTC) on September 11, 2001 released a dust cloud containing numerous environmental contaminants, including polychlorinated dibenzo-para-dioxins and polychlorinated dibenzofurans (PCDD/Fs). PCDD/Fs are toxic and are associated with numerous adverse health outcomes including cancer, diabetes, and impaired reproductive and immunologic function. Prior studies have found adults exposed to the WTC disaster to have elevated levels of PCDD/Fs. This is the first study to assess PCDD/F levels in WTC-exposed children. METHODS:This analysis includes 110 participants, a subset of the 2014-2016 WTC Adolescent Health Study, a group of both exposed youths who lived, attended school, or were present in lower Manhattan on 9/11 recruited from the WTC Health Registry (WTCHR) and unexposed youths frequency matched on age, sex, race, ethnicity, and income. Our sample was selected to maximize the contrast in their exposure to dust from the WTC collapse. Questionnaire data, including items about chronic home dust and acute dust cloud exposure, anthropometric measures, and biologic specimens were collected during a clinic visit. Serum PCDD/F concentrations were measured according to a standardized procedure at the New York State Department of Health Organic Analytical Laboratory. We used multivariable linear regression to assess differences in PCCD/Fs between WTCHR and non-WTCHR participants. We also compared mean and median PCDD/F and toxic equivalency (TEQ) concentrations in our cohort to 2003-4 National Health and Nutrition Examination Survey (NHANES) levels for youths age 12-19. RESULTS:Median PCDD/F levels were statistically significantly higher among WTCHR participants compared to non-WTCHR participants for 16 out of 17 congeners. Mean and median TEQ concentrations in WTCHR participants were >7 times those in non-WTCHR participants (72.5 vs. 10.1 and 25. 3 vs. 3.39pg/g lipid, respectively). Among WTCHR participants, median concentrations of several PCDD/Fs were higher than the NHANES 95th percentiles. After controlling for dust cloud exposure, home dust exposure was significantly associated with higher PCDD/F level. CONCLUSIONS:Adolescents in lower Manhattan on the day of the WTC attack and exposed to particulate contamination from the WTC collapse had significantly elevated PCDD/F levels >12years later compared to a matched comparison group, driven by chronic home dust exposure rather than acute dust cloud exposure. PCDD/F and TEQ levels substantially exceeded those in similar-aged NHANES participants. Future studies are warranted to explore associations of PCDD/Fs with health and developmental outcomes among individuals exposed to the WTC disaster as children.

BACKGROUND AND OBJECTIVE: Few studies have examined the possible cardiometabolic consequences of World Trade Center-related exposures on children who lived and/or attended school near the disaster site. Our objective was to compare cardiometabolic profiles of participants in the World Trade Center Health Registry (WTCHR) with a matched comparison group. METHODS: We evaluated WTCHR enrollees who resided in New York City and were born between September 11, 1993 and September 10, 2001, and a matched comparison group. We assessed exposure to dust cloud, home dust, as well as traumatic exposure, and associations with blood pressure, arterial wall stiffness, body mass index (BMI), total cholesterol, triglycerides, HDL, and LDL. RESULTS: A total of 402 participants completed the study, 222 in the comparison group and 180 in the WTCHR group. In multivariable regression analysis, after adjusting for relevant confounders we detected a weak association between participation in the WTCHR group and lower BMI (-1.12kg/m2, 95% CI -2.11, -0.12; p = 0.03), which became non-significant after adjusting for multiple comparisons. With respect to traumatic and psychosocial exposures, the only association that persisted in our multivariable model, below our predefined level of significance, was between post-traumatic stress disorder and higher BMI (2.06kg/m2, 95% CI 0.37, 3.74; p = 0.02). CONCLUSIONS: Our findings do not support an association between self-reported exposures to the WTC disaster and adverse cardiometabolic profile. However, further longitudinal studies may better inform the full extent of WTC-related conditions associated with exposure to the disaster.

Thyroid hormones are crucial in normal brain development. Transient and mild thyroid hormone insufficiency in pregnancy is also associated with impaired neurodevelopment in the offspring (e.g., 3-4 IQ score loss in association with maternal free thyroxine in the lowest fifth percentile). While inadequate iodine intake remains the most common underlying cause of mild thyroid hormone insufficiency in vulnerable populations including pregnant women, other factors such as exposure to environmental contaminants have recently attracted increasing attention, in particular in interaction with iodine deficiency. Endocrine-disrupting chemicals (EDCs) are natural and synthetic substances with ubiquitous exposure in children and adults including pregnant women. EDCs interfere, temporarily or permanently, with hormonal signaling pathways in the endocrine system by binding to hormone receptors and modifying gene expression. Other mechanisms involve alterations in production, metabolism, and transfer of hormones. Experimental studies have shown that exposures to EDCs affect various brain processes such as neurogenesis, neural differentiation and migration, as well as neural connectivity. Neuroimaging studies confirm brain morphological abnormalities (e.g., cortical thinning) consistent with neurodevelopmental impairments as a result of EDC exposures at standard use levels. In this review, we provide an overview of present findings from toxicological and human studies on the anti-thyroid effect of EDCs with a specific attention to fetal and early childhood exposure. This brief overview highlights the need for additional multidisciplinary studies with a focus on thyroid disruption as an underlying mechanism for developmental neurotoxicity of EDC, which can provide insight into modifiable risk factors of developmental delays in children.

Substantial effort has been devoted to explaining secular trends in childhood obesity and metabolic risks to unhealthy diet and physical activity. While some studies have suggested these factors may play a role in the obesity epidemic, even these studies have only been able to conclude that these factors have a moderate role. Given that a single-generation transformation in the human genome is even more unlikely to have transformed susceptibility to excess weight gain in early life, we are left with the reality that environmental influences represent important risks for obesity and dysmetabolism. In contrast to diet and physical activity, which can require intensive attention, effort and costs to modify through behavioral and other interventions, government action can fundamentally transform the environment and prevent disease and disability. The costs of regulations to limit environmental obesogens can also be much lower than the benefits to society.

Background: suPAR is an inflammatory mediator that has been linked to the pathogenesis of FSGS and progression of chronic kidney disease in children and adults. Overexpression of suPAR leads to reduced nephron development in preclinical models. This study was designed to measure suPAR in pregnant women to determine the range of fetal exposure to this molecule and its potential influence on antenatal human kidney growth.
Method(s): Pregnant women enrolled in the Children's Health and Environment Study (CHES) provided serum samples obtaining during 1-3 trimesters. Clinical information was obtained from the electronic health record. suPAR levels were determined by ELISA (Virogates, Copenhagen, Denmark). Data are presented as mean+/-SD. Results were analyzed by Pearson correlation and ANOVA.
Result(s): 515 mothers were studied, age 31+/-6 yr, and racial distribution 44% Caucasian, 7% African American, 9 % Asian, and 41% other/unspecified. 46% of the women were Hispanic. 29% had completed a high school education or less and 28% had an annual income <$50,000. There were 464 livebirths, 50.4% girls. The serum suPAR levels (mean, SD, minimum, maximum) are summarized in the Table. The suPAR levels in the subgroup of women who provided more than one sample during pregnancy were closely correlated (r=0.79-0.94, P<0.0001)). The decline in serum suPAR levels from trimester 1 to 3 was highly significant (P<0.001).
Conclusion(s): Maternal suPAR levels are detectable throughout pregnancy but decline from trimester 1 to 3. The levels are highly correlated and steady during the course of pregnancy in an individual woman. There is more than a 10-fold range in suPAR concentration which may contribute to the biological variation in nephron number at birth. Follow-up assessment in the infants will be performed in the prospective Environmental Influences on Child Health Outcomes (ECHO) cohort study. (Table Presented)

Background: Environmental chemical exposures are linked to oxidative stress and kidney injury in children and adults. This applies to short-lived organic compounds such as bisphenol A and phthalates and persistent synthetic chemicals such as perfluoroalkyl acids (PFAAs). Most investigations to date have been conducted in developed countries with few data about environmental chemical exposures in children living in Africa.
Method(s): Clinical and laboratory data about pediatric patients enrolled in the H3 Africa observational cohort study including age, gender, BMI, serum creatinine, eGFR, proteinuria were collected. Serum samples that had been collected at enrollment were retrieved from the Biorepository and analyzed for PFAAs and polybrominated diphenyl ethers (PBDEs) and DDE presticides using established methods. Proteinuria was assessed in a first morning urine sample. Results are presented as mean+/-SD.
Result(s): 86 patients with CKD (41 M:45 F), age 12.6+/-2.6 yr old, were included in this nested case control study. The eGFR was 75+/-4 and the albumin:creatinine ratio was 65+/-186. The chemical exposures are summarized in the Table. There was no association between exposure (log of serum concentration) to PFAAs and proteinuria. However, controlling for age, gender, and BMI, there was an inverse relationship between eGFR and exposure to PFNA, -21.2 [95% CI:-41.6 -0.8] and PFDA -18.3 [95% CI:-35.3 --1.3] ml/min/log unit increase in exposure and a trend towards a similar effect for PFOS. PBDE/DDEs were detected in a small fraction of children and because of small sample size associations with effect markers were not made
Conclusion(s): PFAA exposure is substantially lower in H3 Africa participants than in healthy US children, age 12-19 enrolled in NHANES 2003-2010. However, even at these lower levels of exposure there was an adverse association between select PFAAs and GFR. These studies indicate the feasibility of measuring environmental chemical exposure in developing countries. The impact of these chemical exposures on kidney function will require larger cohorts of children followed for more extended periods of time