Children's environmental health in agricultural settings

Climate Change and Children's Health: Building a Healthy Future for Every Child

The warming of our planet matters to every child. Driven by fossil fuel-generated greenhouse gas emissions, climate conditions stable since the founding of modern pediatrics in the mid-nineteenth century have shifted, and old certainties are falling away. Children's physical and mental health are threatened by climate change through its effects on temperature, precipitation, and extreme weather; ecological disruption; and community disruption. These impacts expose and amplify existing inequities and create unprecedented intergenerational injustice. Fossil fuel extraction and combustion cause harm today and reach centuries into the future, jeopardizing the health, safety, and prosperity of today's children and future generations. Appreciating the unique vulnerability of their patients, pediatricians have become leading health advocates for climate actions necessary to protect all living and future children. Policies that reduce reliance on fossil fuels and promote cleaner air, facilitate walking and bicycling, encourage more sustainable diets, increase access to nature, and develop more connected communities lead to immediate gains in child health and equity, and build a foundation for generations of children to thrive.

School Hearing Screening With a Portable, Tablet-Based, Noise-Attenuating Audiometric Headset in Rural Nicaragua

OBJECTIVE

To investigate the utility and effectiveness of a noise-attenuating, tablet-based mobile health system combined with asynchronous telehealth evaluations for screening rural Nicaraguan schoolchildren for hearing loss.

STUDY DESIGN

Prospective population-based survey.

SETTING

Rural Nicaraguan communities.

PATIENTS

There were 3,398 school children 7 to 9 years of age.

INTERVENTIONS

Diagnostic automated and manual audiometry, detailed asynchronous telehealth evaluations.

MAIN OUTCOME MEASURES

Referral rates, ambient noise levels, and audiometric results as well as hearing loss prevalence, types, and risk factors.

RESULTS

Despite high ambient noise levels during screening (46.7 dBA), no effect of noise on referral rates on automated audiometry or confirmatory manual audiometry in those who failed automated testing was seen. The overall audiometric referral rate was 2.6%. Idiopathic sensorineural hearing loss (SNHL) and cerumen impaction were the most common types of hearing loss in this population with an estimated prevalence of hearing loss (all types) of 18.3 per 1,000 children. SNHL was associated with both drug exposure during pregnancy (p = 0.04) and pesticide exposure in the home (p = 0.03).

CONCLUSION

Hearing screening using a tablet-based, noise-attenuating wireless headset audiometer is feasible and effective in rural low-resource environments with moderately elevated ambient noise levels. The referral rate with noise-attenuating headsets was much lower than that previous reports on this population. In addition, manual audiometry resulted in much lower referral rates than automated audiometry. The confirmed hearing loss rate in this study is comparable to reports from other low-income countries that use some form of noise attenuation during screening. Pesticide exposure and drug exposure during pregnancy are potential causes of SNHL in this population.

Food, water, and sanitation insecurities: Complex linkages and implications for achieving WASH security

Food, water and sanitation insecurities are complex, multi-dimensional phenomena that entail more than availability and access; food, water, and sanitation resources must be safe and culturally appropriate. Researchers and implementers concerned with these insecurities have demonstrated that there are notable interactions between them resulting in significant psychological and biological outcomes. Recent randomised controlled trials (RCTs) in Bangladesh, Kenya (WASH Benefits) and Zimbabwe (SHINE) demonstrated no effect from water, sanitation and hygiene (WASH) interventions on linear growth, and mixed evidence on enteropathogen burden and risk of diarrhoea in young children. These data suggest a need for a more comprehensive understanding of WASH security. The risks posed by multiple resource insecurities shift depending on the individual, their movement throughout their day, their economically and socially prescribed roles, and ecological features such as seasonality and precipitation. By more fully integrating food, water and sanitation security in interventions and subsequent impact evaluations, we can achieve WASH security-one that addresses myriad transmission pathways and co-occurring diseases-that ultimately would improve health outcomes throughout the world. In this critical review, we outline the complexity of combined resource insecurities as a step towards transformative WASH.

An expert-driven literature review of "negative" chemicals for developmental neurotoxicity (DNT) in vitro assay evaluation

To date, approximately 200 chemicals have been tested in US Environmental Protection Agency (EPA) or Organization for Economic Co-operation and Development (OECD) developmental neurotoxicity (DNT) guideline studies, leaving thousands of chemicals without traditional animal information on DNT hazard potential. To address this data gap, a battery of in vitro DNT new approach methodologies (NAMs) has been proposed. Evaluation of the performance of this battery will increase the confidence in its use to determine DNT chemical hazards. One approach to evaluate DNT NAM performance is to use a set of chemicals to evaluate sensitivity and specificity. Since a list of chemicals with potential evidence of in vivo DNT has been established, this study aims to develop a curated list of "negative" chemicals for inclusion in a "DNT NAM evaluation set". A workflow, including a literature search followed by an expert-driven literature review, was used to systematically screen 39 chemicals for lack of DNT effect. Expert panel members evaluated the scientific robustness of relevant studies to inform chemical categorizations. Following review, the panel discussed each chemical and made categorical determinations of "Favorable", "Not Favorable", or "Indeterminate" reflecting acceptance, lack of suitability, or uncertainty given specific limitations and considerations, respectively. The panel determined that 10, 22, and 7 chemicals met the criteria for "Favorable", "Not Favorable", and "Indeterminate", for use as negatives in a DNT NAM evaluation set. Ultimately, this approach not only supports DNT NAM performance evaluation but also highlights challenges in identifying large numbers of negative DNT chemicals.

Longitudinal measures of phthalate exposure and asthma exacerbation in a rural agricultural cohort of Latino children in Yakima Valley, Washington

Phthalates are a class of widely used synthetic chemicals found in commonly used materials and products. Epidemiological studies suggest phthalate exposure is associated with asthma outcomes, though most studies have not investigated phthalates as triggers of exacerbations in children diagnosed with asthma. This study used data from the Home Air in Agriculture Pediatric Intervention Trial (HAPI) to examine relationships between phthalate exposure and outcomes related to childhood asthma exacerbation. We used measures of phthalate metabolites and respiratory health measures including fractional exhaled nitric oxide (FENO), the Asthma Control Test (ACT), caregiver report of symptoms, and urinary leukotriene E₄ (uLTE₄) to estimate longitudinal associations using mixed effects models, adjusted for covariates. For 100% (i.e., doubling) increases in mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP), mono-2-ethylhexyl phthalate (MEHP), and mono-ethyl phthalate (MEP), concentrations of FENO increased by 8.7% (95% CI: 0.7-17.3), 7.2% (95% CI: 0.0-14.9), and 6.4% (95% CI: 0.0-13.3), respectively. All phthalate metabolites demonstrated associations with uLTE₄, effect sizes ranging from an 8.7% increase in uLTE₄ (95% CI: 4.3-12.5) for a 100% increase in MEHP to an 18.1% increase in uLTE₄ (95% CI: 13.3-23.1) for a 100% increase in MNBP. In models of caregiver report of symptoms, no phthalate metabolites were significantly associated in primary models. No phthalate metabolites were associated with standardized ACT score. Our results suggest urinary phthalate metabolites are significant predictors of inflammatory biomarkers related to asthma exacerbation in children but not child and caregiver report of airway symptomatology.

Spatiotemporal variations in the association between particulate matter and airborne bacteria based on the size-resolved respiratory tract deposition in concentrated layer feeding operations

Bacterial loading aggravates the health and environmental hazards of particulate matter (PM), particularly in concentrated animal feeding operations. Understanding the association between PM and airborne bacteria is conducive to accurately assessing occupational exposure, providing fundamental data for exposure mitigation via engineering solutions, and providing information regarding the physical properties influencing the transmission of airborne microorganisms at emission sources. In this work, we conducted a joint study to systematically determine the concentrations and size distributions of PM and airborne bacteria, and establish the quantitative relationship between PM and airborne bacteria in laying hen houses. The association between PM and airborne bacteria was expressed as the load of airborne bacteria on PM in terms of the identical particle size interval based on the size-resolved respiratory tract deposition. The concentrations and size distributions of PM and airborne bacteria in laying hen houses were affected by the in-house space (upper and lower), chicken activity (day and night), and outside temperature. The size distributions of PM and airborne bacteria indicated that the mass concentration of large particles decreased with increasing outside temperature, while the concentration of airborne bacteria loaded on the small particles increased with increasing outside temperature. The results indicated that particles with diameters ranging from 2.1 to 4.7 μm carried the most airborne bacteria. Therefore, particles with diameters ranging from 2.1 to 4.7 μm should be the focus of future experimental research on occupational exposure, air quality improvement, and the airborne transmission of PM and airborne microorganisms originating from concentrated layer feeding operations.

Respiratory Health and Suspected Asthma among Hired Latinx Child Farmworkers in Rural North Carolina

The aim of this study was to evaluate respiratory health problems, including suspected asthma, and healthcare provider utilization among a sample of Latinx hired child farmworkers in rural North Carolina (n = 140). In 2018, a respiratory health questionnaire and breathing tests were collected from Latinx child (11–19 years) farmworkers (35.0% girls and 65.0% boys). Overall, 21.4% of children reported having been told by a medical provider that they had asthma, yet based on a combination of responses to respiratory survey questions, 36.4% or 15% more were identified as having suspected asthma. While 56.4% reported having a regular medical doctor, 38% had not had a medical exam in the past year. Respiratory dysfunction, including suspected, or uncontrolled asthma was prevalent among this group. Latinx children working in agriculture are vulnerable to occupational hazards and exposures and require assurances that they will receive access to high quality healthcare services that include routine respiratory health screenings.

Characterizing the joint effects of pesticide exposure and criteria ambient air pollutants on pediatric asthma morbidity in an agricultural community

Supplemental Digital Content is available in the text.

Background:

Environmental contributions to pediatric asthma morbidity have been studied extensively in urban settings; exposures characteristic of agricultural and rural communities have received less attention despite a comparable burden of morbidity.

Methods:

We obtained repeated urine samples (n = 139) from 16 school-age children with asthma in the Yakima Valley of Washington State between July and October 2012. Biomarkers of organophosphate (OP) pesticide exposure (dialkyl phosphates [DAPs]) and asthma exacerbation (leukotriene E4 [LTE4]) were analyzed in samples. Corresponding 24-hour average particulate matter <2.5 μg (PM_2.5) and maximum 8-hour ozone concentration data for the study period were available from local monitoring stations. We evaluated the independent and multi-pollutant associations between LTE4 and exposure to ambient air pollutants and DAPs using generalized estimating equations. For multi-domain and multi-pollutant models, we created categorized pollution combination levels and estimated the relative health impact of exposure to pollutant mixtures.

Results:

In single-pollutant models, an interquartile range increase in exposures to DAPs was associated with increase in LTE4 levels (β: 4.1 [0.6–7.6] pg/mg). PM_2.5 and ozone were also associated with increase in LTE4, though confidence intervals contained the null value. Increase in LTE4 levels was consistently associated with increase in median-dichotomized multi-pollutant combination exposures; the highest effect estimates were observed with joint highest (vs. the lowest) category of the three-pollutant exposure (PM_2.5, ozone, and OP; β: 53.5, 95% confidence interval = 24.2, 82.8 pg/mg).

Conclusion:

Concurrent short-term exposure to criteria air pollutants and OPs in an agricultural community was associated with an increase in a marker of asthma morbidity.

Association of Organophosphate Pesticide Exposure and a Marker of Asthma Morbidity in an Agricultural Community

Objectives: We explored the short-term impact of pesticide exposure on asthma exacerbation among children with asthma in an agricultural community.Methods: We obtained repeated urine samples from a subset of 16 school-age children with asthma (n = 139 samples) as part of the Aggravating Factors of Asthma in a Rural Environment (AFARE) study cohort. Biomarkers of organophosphate (OP) pesticide exposure (dialkylphosphates (DAPs)), and asthma exacerbation (leukotriene E4 (uLTE4)) were assessed in urine samples. We used generalized estimating equations to examine the association of summed measures of creatinine-adjusted DAPs (total dimethyl alkylphosphate (EDM), total diethyl alkylphosphate (EDE), and total dialkylphosphate pesticides (EDAP)) and uLTE4 concentration, adjusting for multiple confounders, yielding beta-coefficients with 95% CIs.Results: A total of 139 observations were obtained from the 16 children over the study period, the total number of samples per subject ranged from 1 to 12 (median: 10.5). The geometric mean (GM) of creatinine-adjusted EDE, EDM, and EDAP in this population were 81.0, 71.8 and 168.0 nmol/g, respectively. Increase in uLTE4 levels was consistently associated with increased exposures to DAPs (interquartile range in μg/g): β_EDE: 8.7 (95%CI: 2.8, 14.6); β_EDM: 1.1 (0.5, 1.7); β_EDAP: 4.1 (0.7, 7.5).Conclusion: This study suggests that short-term OP exposure is associated with a higher risk of asthma morbidity, as indicated by increased uLTE4 levels in this cohort of children with asthma in an agricultural community. Additional studies are required to confirm these adverse effects, and explore the mechanisms underlying this relationship.

Application of Microelectrode Array Approaches to Neurotoxicity Testing and Screening

Neurotoxicity can be defined by the ability of a drug or chemical to alter the physiology, biochemistry, or structure of the nervous system in a manner that may negatively impact the health or function of the individual. Electrophysiological approaches have been utilized to study the mechanisms underlying neurotoxic actions of drugs and chemicals for over 50 years, and in more recent decades, high-throughput patch-clamp approaches have been utilized by the pharmaceutical industry for drug development. The use of microelectrode array recordings to study neural network electrophysiology is a relatively newer approach, with commercially available systems becoming available only in the early 2000s. However, MEAs have been rapidly adopted as a useful approach for neurotoxicity testing. In this chapter, I will review the use of MEA approaches as they have been applied to the field of neurotoxicity testing, especially as they have been applied to the need to screen large numbers of chemicals for neurotoxicity and developmental neurotoxicity. In addition, I will also identify challenges for the field that when addressed will improve the utility of MEA approaches for toxicity testing.

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.

Children's Environmental Health in Thailand: Past, Present, and Future

Background:

There is increasing evidence of a link between environmental pollution and preventable diseases in developing countries, including Thailand. Economic development has generated several types of pollution that can affect population health. While these environmental health effects can be observed throughout life, pregnant women and children represent particularly vulnerable and sensitive groups.

Methods:

The published epidemiological literature investigating environmental chemical exposure in Thai children was reviewed, highlighting those that investigated associations between exposure and subsequent health outcomes.

Results:

The majority of the Thai epidemiological studies on environmental health in children were cross-sectional in design, with some demonstrating associations between exposure and outcome. The three main types of chemical exposure in Thai children were pesticides, heavy metals, and air pollution, which resulted from agricultural activities in countryside areas, industrial zones (both registered and unregistered establishments), mining, and traffic in inner cities. Major health outcomes included detrimental effects on cognitive function and cancer risk. Pesticide exposure was focused on, but not limited to, agricultural areas. The success of the Thai environmental policy to introduce lead–free petrol can be demonstrated by the decline of mean blood lead levels in children, particularly in urban areas. However, unregistered lead-related factories and smelters act as hidden sources. In addition, there is increasing concern, but little acknowledgement, about the effects of chronic arsenic exposure related to mining. Lastly, air pollution remains a problem in both dense city populations due to traffic and in rural areas due to contamination of indoor air and house dust with heavy metals, endotoxins and other allergens.

Conclusions:

The increasing number of published articles demonstrates an improved awareness of children’s environmental health in Thailand. Chemical hazards, including the improper use of pesticides, environmental contamination with heavy metals (lead and arsenic), and air pollution in inner cities and indoor air, continue to be growing issues.

Determinants of Sunburn and Sun Protection of Agricultural Workers During Occupational and Recreational Activities

OBJECTIVE

The aim of this study was to identify determinants of occupational sunburn in agricultural workers and assess their occupational and recreational sun protection habits.

METHODS

Specific surveys of agricultural workers in Switzerland and France were conducted (N = 1538). Multivariate logistic regressions identified occupational sunburn determinants. Occupational and recreational sun protection habits were estimated and correlated.

RESULTS

One-year occupational and recreational sunburn prevalences were 19.8% and 11.5%, respectively. Occupational sunburn increased with having a recent recreational sunburn, highly sensitive skin, young age, high perceived skin cancer risk, using sunscreen, and not wearing a hat. Correlation between protection habits during work and leisure was substantial (rs 0.5 to 0.7). Skin health knowledge was high and pro-tanning attitude moderate.

CONCLUSION

Potentially modifiable sunburn determinants and suboptimal recreational and occupational sun protection practices were identified in agricultural workers. Refining and tailoring sun protection messages targeting the agricultural sector are needed.

Environmental exposure and effects on health of children from a tobacco-producing region

Children may be environmentally exposed to several hazards. In order to evaluate the health of children living in a tobacco-producing region, different biomarkers of exposure and effect, as well as hematological parameters, were evaluated. Biomarkers of exposure to the following xenobiotics were assessed: pesticides, nicotine, toxic elements, and organic solvents. Oxidative damage markers malondialdehyde (MDA) and protein carbonyls (PCO), vitamin C, microalbuminuria (mALB) levels, and N-acetyl-β-D-glucosaminidase (NAG) activity were also evaluated. Peripheral blood samples and urine were collected from 40 children (6-12 years), at two different crop periods: in the beginning of pesticide applications (period 1) and in the leaf harvest (period 2). The Wilcoxon signed-rank test for paired data was used to evaluate the differences between both periods. Biomarkers of exposure cotinine in urine and blood chromium (Cr) levels were increased in period 1 when compared to period 2. Moreover, a significant reduced plasmatic activity of butyrylcholinesterase (BuChE) was observed in period 2 in relation to period 1. Blood Cr levels were above the recommended by WHO in both evaluations. The biomarkers MDA and PCO as well as the kidney dysfunction biomarker, mALB, presented levels significantly increased in period 1. Additionally, decreased lymphocytes and increased basophils were also observed. Cotinine was positively associated with PCO, and Cr was positively associated with PCO and MDA. The increased Cr levels were associated with decreased lymphocytes and increased basophils. Our findings demonstrate that children environmentally exposed to xenobiotics in rural area may present early kidney dysfunction, hematological alterations, as well as lipid and protein damages, associated with co-exposure to different xenobiotics involved in tobacco cultivation.

Expanding the test set: Chemicals with potential to disrupt mammalian brain development

High-throughput test methods including molecular, cellular, and alternative species-based assays that examine critical events of normal brain development are being developed for detection of developmental neurotoxicants. As new assays are developed, a "training set" of chemicals is used to evaluate the relevance of individual assays for specific endpoints. Different training sets are necessary for each assay that would comprise a developmental neurotoxicity test battery. In contrast, evaluation of the predictive ability of a comprehensive test battery requires a set of chemicals that have been shown to alter brain development after in vivo exposure ("test set"). Because only a small number of substances have been well documented to alter human neurodevelopment, we have proposed an expanded test set that includes chemicals demonstrated to adversely affect neurodevelopment in animals. To compile a list of potential developmental neurotoxicants, a literature review of compounds that have been examined for effects on the developing nervous system was conducted. The search was limited to mammalian studies published in the peer-reviewed literature and regulatory studies submitted to the U.S. EPA. The definition of developmental neurotoxicity encompassed changes in behavior, brain morphology, and neurochemistry after gestational or lactational exposure. Reports that indicated developmental neurotoxicity was observed only at doses that resulted in significant maternal toxicity or were lethal to the fetus or offspring were not considered. As a basic indication of reproducibility, we only included a chemical if data on its developmental neurotoxicity were available from more than one laboratory (defined as studies originating from laboratories with a different senior investigator). Evidence from human studies was included when available. Approximately 100 developmental neurotoxicity test set chemicals were identified, with 22% having evidence in humans.