Children's Environmental Health: A Brief History

Exposures to pesticides and risk of cancer: Evaluation of recent epidemiological evidence in humans and paths forward

Knowledge of the role in cancer etiology of environmental exposures as pesticides is a prerequisite for primary prevention. We review 63 epidemiological studies on exposure to pesticides and cancer risk in humans published from 2017 to 2021, with emphasis on new findings, methodological approaches, and gaps in the existing literature. While much of the recent evidence suggests causal relationships between pesticide exposure and cancer, the strongest evidence exists for acute myeloid leukemia (AML) and colorectal cancer (CRC), diseases in which the observed associations were consistent across several studies, including high-quality prospective studies and those using biomarkers for exposure assessment, with some observing dose-response relationships. Though high-quality studies have been published since the IARC monograph on organophosphate insecticides in 2017, there are still gaps in the literature on carcinogenic evidence in humans for a large number of pesticides. To further knowledge, we suggest leveraging new techniques and methods to increase sensitivity and precision of exposure assessment, incorporate multi-omics data, and investigate more thoroughly exposure to chemical mixtures. There is also a strong need for better and larger population-based cohort studies that include younger and nonoccupationally exposed individuals, particularly during developmental periods of susceptibility. Though the existing evidence has limitations, as always in science, there is sufficient evidence to implement policies and regulatory action that limit pesticide exposure in humans and, hence, further prevent a significant burden of cancers.

Children Environmentally Exposed to Agrochemicals in Rural Areas Present Changes in Oxidative Status and DNA Damage

Rural children are exposed to several chemicals. This study evaluated the environmental co-exposure of rural children to cholinesterase inhibitor insecticides and metals/metalloids, and the resulting oxidative stress and DNA damage. Seventy-two children (5 to 16 years old) were studied at two different moments: period 1, when agrochemicals were less used, and period 2, when agrochemicals were extensively used in agriculture. Biomonitoring was performed by evaluating butyrylcholinesterase (BuChE) activity in serum; arsenic (As), chromium (Cr), lead (Pb), and nickel (Ni) levels in blood; malondialdehyde (MDA) in plasma; glutathione peroxidase (GSH-Px) and glutathione S-transferase (GST) activities in whole blood; non-protein thiol levels in erythrocytes; and micronuclei (MN) assay in exfoliated buccal cells. Cr and As levels were higher than the reference values in both periods, and Ni levels were higher than the reference values in period 2 alone. BuChE activity was inhibited in period 2 compared with period 1. In period 2, there was an increase in endogenous antioxidants and a decrease in MDA, probably demonstrating a compensatory mechanism as a response to increasing xenobiotics. Also in period 2, the MN frequency increased and BuChE and As were positively associated, suggesting co-exposure. On the other hand, in period 1, it was observed that Cr, Ni, and Pb blood levels were negatively associated with GSH-Px and GST, while MDA was positively associated with As levels. Our findings demonstrated an imbalance in endogenous antioxidants, contributing to genotoxicity and lipoperoxidation, probably in response to exposure to xenobiotics, especially carcinogenic elements (Cr, As, and Ni).

The EPA's Commitment to Children's Environmental Health: History and Current Challenges

Children's environmental health (CEH) has a 25-year history at the US Environmental Protection Agency (EPA), during which the agency has advanced CEH through research, policy, and programs that address children's special vulnerability to environmental harm. However, the Trump administration took many actions that weakened efforts to improve CEH. The actions included downgrading or ignoring CEH concerns in decision-making, defunding research, sidelining the Children's Health Protection Advisory Committee, and rescinding regulations that were written in part to protect children. To improve CEH, federal environmental statutes should be reviewed to ensure they are sufficiently protective. The administrator should ensure the EPA's children's health agenda encompasses the most important current challenges and that there is accountability for improvement. Guidance documents should be reviewed and updated to be protective of CEH and the federal lead strategy refocused on primary prevention. The Office of Children's Health Protection's historically low funding and staffing should be remedied. Finally, the EPA should update CEH data systems, reinvigorate the role of the Children's Health Protection Advisory Committee, and restore funding for CEH research that is aligned with environmental justice and regulatory decision-making needs. (Am J Public Health. 2022;112(1):124-134. https://doi.org/10.2105/AJPH.2021.306537).

Children and Youth Environmental Action: The Case of Children and Youth with Disabilities

Youth environmental activism is on the rise. Children and youth with disabilities are disproportionally impacted by environmental problems and environmental activism. They also face barriers towards participating in activism, many of which might also apply to their participation in environmental activism. Using a scoping review approach, we investigated the engagement with children and youth with disabilities by (a) academic literature covering youth environmental activism and their groups and (b) youth environmental activism group (Fridays For Future) tweets. We downloaded 5536 abstracts from the 70 databases of EBSCO-HOST and Scopus and 340 Fridays For Future tweets and analyzed the data using directed qualitative content analysis. Of the 5536 abstracts, none covered children and youth with disabilities as environmental activists, the impact of environmental activism or environmental problems such as climate change on children and youth with disabilities. Fourteen indicated that environmental factors ‘caused’ the ‘impairments’ in children and youth with disabilities. One suggested that nature could be beneficial to children and youth with disabilities. The tweets did not mention children and youth with disabilities. Our findings suggest the need for more engagement with children and youth with disabilities in relation to youth environmental activism and environmental challenges.

Metal-mixtures in toenails of children living near an active industrial facility in Los Angeles County, California

BACKGROUND

Children residing in communities near metalworking industries are vulnerable to multiple toxic metal exposures. Understanding biomarkers of exposure to multiple toxic metals is important to characterize cumulative burden and to distinguish potential exposure sources in such environmental justice neighborhoods impacted by industrial operations. Exposure to metal mixtures has not been well-characterized among children residing in the United States, and is understudied in communities of color.

METHODS

In this study we used toenail clippings, a noninvasive biomarker, to assess exposure to arsenic (As), cadmium (Cd), mercury (Hg), manganese (Mn), lead (Pb), antimony (Sb), selenium (Se), and vanadium (V). We used nonnegative matrix factorization (NMF) to identify "source" signatures and patterns of exposure among predominantly working class Latinx children residing near an industrial corridor in Southeast Los Angeles County. Additionally, we investigated the association between participant demographic, spatial, and dietary characteristics with identified metal signatures.

RESULTS

Through NMF, we identified three groupings (source factors) for the metal concentrations in children's toenails. A grouping composed of Sb, Pb, As, and Cd, was identified as a potential industrial source factor, reflective of known airborne elemental emissions in the industrial corridor. We further identified a manganese source factor primarily composed of Mn, and a potential dietary source factor driven by Se and Hg. We observed differences in the industrial source factor by age of participants, while the dietary source factor varied by neighborhood.

CONCLUSION

Utilizing an unsupervised dimension reduction technique (NMF), we identified a "source signature" of contamination in toenail samples from children living near metalworking industry. Investigating patterns and sources of exposures in cumulatively burdened communities is necessary to identify appropriate public health interventions.

Demographic predictors of urinary arsenic in a low-income predominantly Hispanic pregnancy cohort in Los Angeles

BACKGROUND

Arsenic (As) is a contaminant of top public health concern, due to its range of detrimental health effects. Arsenic exposure has not been well-characterized among the US Hispanic populations and has been particularly understudied in this population during pregnancy.

METHODS

As part of the MADRES ongoing pregnancy cohort of predominantly lower-income, Hispanic women in Los Angeles, CA, we examined levels of maternal first trimester urinary As, including total As and As metabolites (inorganic (iAs), monomethylated (MMA) and dimethylated As (DMA)), in relation to participant demographics, lifestyle characteristics, and rice/seafood consumption, to identify factors that may influence As exposure and its metabolites during pregnancy (N = 241).

RESULTS

Total As concentrations ranged from low to high (0.8-506.2 μg/L, mean: 9.0 μg/L, SD: 32.9) in our study population. Foreign-born Hispanic women had 8.6% higher %DMA (95% CI: 3.3%, 13.9%) and -7.7% lower %iAs (95% CI: -12.6%, -2.9%) than non-Hispanic women. A similar trend was observed for US-born Hispanic women. In addition, maternal age was associated with 0.4% higher %iAs (95% CI: 0.1%, 0.6%) and 0.4% lower %DMA (95% CI: -0.7%, -0.1%) per year, which may indicate poor As methylation capacity.

CONCLUSION

Individual factors may predict As exposure and metabolism in pregnancy, and in turn, greater risk of adverse health effects.

Mother-child transfer rates of organohalogen compounds up to four years of age

BACKGROUND

Breastfed children absorb persistent and toxic chemicals such as organohalogen compounds (OHCs) during the entire lactation period. Nursing is a main contributor to the burden of these pollutants in the first years of life, hence further assessments on the OHC load processes are needed.

OBJECTIVES

To identify the determinants of OHC increase in children at four years of age, considering concentration gains, maternal venous concentrations and breastfeeding time.

METHODS

Concentrations of 19 organochlorine compounds (OCs) and 14 polybrominated diphenyl ethers (PBDEs) were analyzed in maternal venous (n = 466), cord blood (n = 326) and children venous serum at four years of age (n = 272) in the Asturias INMA cohort representing the Spanish general population. Data were evaluated considering the socio-demographic and individual information collected at recruitment and follow up surveys, as well as the OHC physical-chemical constants.

RESULTS

The four years-old children concentration gains of the most abundant OHCs showed strong correlations (R² = 0.65-0.93) with the maternal concentrations during pregnancy and lactation period. The child gain/maternal transfer rates of most correlated pollutants were similar.

DISCUSSION

Between 65 and 93% of the variance of OCs in four years-old children was explained by the maternal concentrations during pregnancy and the lactation period. The compounds with log(Kow) > 3.7 (hydrophobic) showed analogous child gain/maternal transfer rates indicating similar processes of membrane lipid dissolution and passive diffusion from the epithelial cells into the milk. Molecular weight of these pollutants did not influence on these rates. Compounds with low log(Koa) such as hexachlorobenzene are more volatile and less retained, involving lower child gain/maternal transfer rates. These results may be useful to anticipate the increase of the concentrations of OCs in children using the maternal concentration of these compounds during pregnancy and the planned lactation period and to implement prophylactic measures in mothers with high venous pollutant concentrations.

Precautionary Principle: Cancer Prevention Efforts During Critical Periods of Growth and Development

Although the mechanisms of action for all cancer types are not fully known, best practice recommends promoting a healthy lifestyle while avoiding certain substances. Based on environmental science, the precautionary principle is a guideline that suggests that preventive action should be taken when the effects of a substance are unknown or disputed. Oncology nurses and maternal child healthcare professionals can improve cancer prevention through efforts during pregnancy, childhood, adolescence, and adulthood. This article reviews the application of the precautionary principle during critical periods of growth and development and provides recommendations that may prevent epigenetic changes and reduce the risk for cancer.

Environmental Politics of Reproduction

What constitutes "human reproduction" is under negotiation as its biology, social nature, and cultural valences are increasingly perceived as bound up in environmental issues. This review maps the growing overlap between formerly rather separate domains of reproductive politics and environmental politics, examining three interrelated areas. The first is the emergence of an intersectional environmental reproductive justice framework in activism and environmental health science. The second is the biomedical delineation of the environment of reproduction and development as an object of growing research and intervention, as well as the marking off of early-life environments as an "exposed biology" consequential to the entire life span. Third is researchers' critical engagement with the reproductive subject of environmental politics and the lived experience of reproduction in environmentally dystopic times. Efforts to rethink the intersections of reproductive and environmental politics are found throughout these three areas.

Building Capacity in Pediatric Environmental Health: The Academic Pediatric Association's Professional Development Program

BACKGROUND

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.

OBJECTIVE

Describe the APA's professional development program in PEH and assess its impact by tracking careers of former trainees.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Exposure to environment chemicals and its possible role in endocrine disruption of children from a rural area

Endocrine disrupting chemicals (EDCs), including pesticides and metals, are present in rural areas, endangering the health of exposed populations. This work aimed to investigate the possible association between the exposure to these xenobiotics and thyroid dysfunction in children living in a rural community of Southern Brazil. Fifty-four children aged 5-16 years participated in this study. Peripheral biomarker evaluations were performed in periods of low and high exposure to pesticides. Thyroid ultrasonography was evaluated in the high exposure period. Blood levels of chromium (Cr), manganese (Mn), mercury (Hg), and lead (Pb), as well as hair Pb levels were positively correlated with thyroid stimulating hormone (TSH) concentrations and negatively associated with free thyroxine (fT4) levels in the low exposure period. Prolactin was positively associated with hair Mn in both periods. In the ultrasound tests, the majority of children presented a normal echogenicity of thyroid. Glucose was inversely associated with the biomarker of exposure to cholinesterase inhibitor insecticides, butyrylcholinesterase (BuChE). Lipid profile was above the recommended levels in both periods. In summary, our results show that children environmentally exposed to a mixture of xenobiotics in an agricultural community may have health impairments, especially on thyroid function, dyslipidemia, and glucose homeostasis disruption.

Growth and development in school-age children from Rostov region, Russia: Comparison between urban and rural settings

The purposes of the current study were: (1) to describe growth and physical development and establish norms for schoolchildren from Rostov region in Russia; (2) to compare major characteristics of development between urban and rural children by sex and age. Nearly 200,000 children (198,712) aged between 7 and 17 years from 232 urban and rural schools of Rostov region (Southern Federal District of Russia) participated in the study. School age is a period of intensive growth and physiological and psychological development. Irregularities of personal development are caused by a multitude of factors, such as sex differences, heredity, socio-economic status of a family, standard of living, particular environmental conditions, and lifestyle. It has been established that children from the Southern Federal District of Russia had body mass index values higher than age-appropriate norms for all Russians (Total Russian, Rudnev et al., 2014) and World Health Organization charts. Children from urban settings were taller and heavier than children from rural settings. Sex is one of the most influential factors which play key role in determining specific characteristics of growth and personal development. According to our results, boys and girls both had similar age-related changes in weight and height, but their respective dynamics differed. Girls' height and weight values accelerated at the age 10 to 12 years and plateaued after the age fourteen, whereas in boys height and weight steadily increased with age, showing slight acceleration at the age 12 to 13 years, and reached a plateau by the age of seventeen.

Childhood pesticide poisoning in Zhejiang, China: a retrospective analysis from 2006 to 2015

Background

Pesticide poisoning in children has been a serious public health issue around the world, especially in the developing countries where agriculture is still one of the largest economic sectors. The purpose of this study was to analyze epidemiological characteristics of acute pesticide poisoning in children from Zhejiang province, China.

Methods

The pesticide poisoning cases for children were retrieved from Occupational Disease Surveillance and Reporting System, Zhejiang Provincial Center for Disease Control and Prevention, China. The incident cases, deaths, and fatality rate of child pesticide poisoning from 2006 through 2015 were calculated.

Results

During the study period, totally 2952 children were poisoned by pesticides, with 66 deaths, resulting in a fatality rate of 2.24%. Among them, there were 1607 male cases with 28 deaths, and 1345 female cases with 38 deaths. Most of the cases occurred in preschool children (1349) and adolescent age group (1269). Organophosphate and carbamate insecticides were the cause of most poisonings (1130), leading to 34 deaths. The highest fatality rate (3.13%) was due to poisoning by herbicides and fungicides, causing 14 deaths out of 448 cases. Poisoning occurred mostly in rural areas (78%). And most pesticide poisoning occurred in the summer (896) and fall (811), while fewest poisoning cases in the winter (483) but with the highest fatality rate (3.52%).

Conclusions

This study shows that pesticide poisoning of children is a major health problem in Zhejiang, suggesting preventive strategies should be conducted to control childhood pesticide poisoning.

Transdisciplinary approaches enhance the production of translational knowledge

The primary goal of translational research is to generate and apply knowledge that can improve human health. Although research conducted within the confines of a single discipline has helped us to achieve this goal in many settings, this unidisciplinary approach may not be optimal when disease causation is complex and health decisions are pressing. To address these issues, we suggest that transdisciplinary approaches can facilitate the progress of translational research, and we review publications that demonstrate what these approaches can look like. These examples serve to (1) demonstrate why transdisciplinary research is useful, and (2) stimulate a conversation about how it can be further promoted. While we note that open-minded communication is a prerequisite for germinating any transdisciplinary work and that epidemiologists can play a key role in promoting it, we do not propose a rigid protocol for conducting transdisciplinary research, as one really does not exist. These achievements were developed in settings where typical disciplinary and institutional barriers were surmountable, but they were not accomplished with a single predetermined plan. The benefits of cross-disciplinary communication are hard to predict a priori and a detailed research protocol or process may impede the realization of novel and important insights. Overall, these examples demonstrate that enhanced cross-disciplinary information exchange can serve as a starting point that helps researchers frame better questions, integrate more relevant evidence, and advance translational knowledge more effectively. Specifically, we discuss examples where transdisciplinary approaches are helping us to better explore, assess, and intervene to improve human health.

Zebrafish in Toxicology and Environmental Health

As manufacturing processes and development of new synthetic compounds increase to keep pace with the expanding global demand, environmental health, and the effects of toxicant exposure are emerging as critical public health concerns. Additionally, chemicals that naturally occur in the environment, such as metals, have profound effects on human and animal health. Many of these compounds are in the news: lead, arsenic, and endocrine disruptors such as bisphenol A have all been widely publicized as causing disease or damage to humans and wildlife in recent years. Despite the widespread appreciation that environmental toxins can be harmful, there is limited understanding of how many toxins cause disease. Zebrafish are at the forefront of toxicology research; this system has been widely used as a tool to detect toxins in water samples and to investigate the mechanisms of action of environmental toxins and their related diseases. The benefits of zebrafish for studying vertebrate development are equally useful for studying teratogens. Here, we review how zebrafish are being used both to detect the presence of some toxins as well as to identify how environmental exposures affect human health and disease. We focus on areas where zebrafish have been most effectively used in ecotoxicology and in environmental health, including investigation of exposures to endocrine disruptors, industrial waste byproducts, and arsenic.

Two Decades of Enhancing Children's Environmental Health Protection at the U.S. Environmental Protection Agency

This article provides an overview of public health efforts by the U.S. Environmental Protection Agency (EPA) during the past two decades to protect children’s health from environmental hazards. It highlights examples of concrete steps and accomplishments toward improving environmental protection and health outcomes achieved through public policy, rules and regulations, increased scientific understanding, and public health messaging. Additionally, examples of future challenges for better understanding and improving children’s environmental health are discussed.

Food contaminants and programming of type 2 diabetes: recent findings from animal studies

It is now accepted that the way our health evolves with aging is intimately linked to the quality of our early life. The present review highlights the emerging data of Developmental Origins of Health and Disease field on developmental disruption by toxicants and their subsequent effect on type 2 diabetes. We report adverse neonatal effects of several food contaminants during pregnancy and lactation, among them bisphenol A, chlorpyrifos, perfluorinated chemicals on pancreas integrity and functionality in later life. The described alterations, in conjunction with disruption of β cell mass in early life, can lead to dysregulation of glucose metabolism, insulin synthesis, which facilitates the development of insulin resistance and progression of diabetes in the adult. Despite limited and often inconclusive epidemiologic and experimental data, more recent data clearly show that infants appear to be at increased risk of type 2 diabetes in later life. This may be a result of continued exposure to chemical food contaminants during the critical window of pancreas development. In societies already burdened with increased incidence of non-communicable chronic diseases, there is a clear need for information regarding the potential harmful effects of chemical food contaminants on adult health diseases.

Where Do Epigenetics and Developmental Origins Take the Field of Developmental Psychopathology?

The time is ripe for upgrading or rethinking the assumed paradigms for how we study developmental psychopathology. The classic transactional models appear robust but need specification in terms of biological and psychosocial processes. That specification is increasingly tractable due to developments in genetics, epigenetics, the measurement of psychosocial processes, and theory and data on developmental origins of health and disease. This essay offers a high-level view of where the field has been and where it may be going in regard to nosology and conceptions of etiology. Remarks seek to consider rapidly evolving contexts not only for children, but also for the science itself due to progress in our field and in neighboring fields. Illustrations are provided as to how syndromal nosology can be enriched and advanced by careful integration with biologically relevant behavioral dimensions and application of quantitative methods. It is concluded that a revised, forward-looking, transactional model of abnormal child psychology will incorporate prenatal and postnatal developmental programming, epigenetic mechanisms and their associated genotype x environment interactions, and inflammatory processes as a potential common mediator influencing numerous health and mental health conditions.