Chronic exposure to organophosphate (OP) pesticides and neuropsychological functioning in farm workers: a review

The research landscape concerning environmental factors in neurodevelopmental disorders: Endocrine disrupters and pesticides-A review

In recent years, environmental epidemiology and toxicology have seen a growing interest in the environmental factors that contribute to the increased prevalence of neurodevelopmental disorders, with the purpose of establishing appropriate prevention strategies. A literature review was performed, and 192 articles covering the topic of endocrine disruptors and neurodevelopmental disorders were found, focusing on polychlorinated biphenyls, polybrominated diphenyl ethers, bisphenol A, and pesticides. This study contributes to analyzing their effect on the molecular mechanism in maternal and infant thyroid function, essential for infant neurodevelopment, and whose alteration has been associated with various neurodevelopmental disorders. The results provide scientific evidence of the association that exists between the environmental neurotoxins and various neurodevelopmental disorders. In addition, other possible molecular mechanisms by which pesticides and endocrine disruptors may be associated with neurodevelopmental disorders are being discussed.

Association of pesticide exposure with neurobehavioral outcomes among avocado farmworkers in Mexico

BACKGROUND AND AIM

To date, few studies have focused on the health effects of pesticide exposure among avocado farmworkers. We examined the association of exposure to insecticides, fungicides, and herbicides with cognitive and mental health outcomes among these avocado workers from Michoacan, Mexico.

MATERIALS AND METHODS

We conducted a cross-sectional study of 105 avocado farmworkers between May and August 2021. We collected data on self-reported pesticide use during the 12 months prior to the baseline survey and estimated annual exposure-intensity scores (EIS) using a semi-quantitative exposure algorithm. We calculated specific gravity adjusted average concentrations of 12 insecticide, fungicide, or herbicide metabolites measured in urine samples collected during two study visits (8-10 weeks apart). We assessed participants' cognitive function and psychological distress using the NIH Toolbox Cognition Battery and the Brief Symptom Inventory 18 (BSI-18), respectively. We examined individual associations of EIS and urinary pesticide metabolites with neurobehavioral outcomes using generalized linear regression models. We also implemented Bayesian Weighted Quantile Sum (BWQS) regression to evaluate the association between a pesticide metabolite mixture and neurobehavioral outcomes.

RESULTS

In individual models, after adjusting for multiple comparisons, higher concentrations of hydroxy-tebuconazole (OH-TEB, metabolite of fungicide tebuconazole) were associated with higher anxiety (IRR per two-fold increase in concentrations = 1.26, 95% CI:1.08, 1.48) and Global Severity Index (GSI) (IRR = 1.89, 95% CI:1.36, 2.75) scores, whereas higher concentrations of 3,5,6-trichloro-2-pyridinol (TCPy, metabolite of chlorpyrifos) were associated with lower GSI scores (IRR = 0.69, 95% CI: 0.56, 0.85). In BWQS analyses, we found evidence of a mixture association of urinary pesticide metabolites with higher anxiety (IRR = 1.72, 95% CrI: 1.12, 2.55), depression (IRR = 4.60, 95% CrI: 2.19, 9.43), and GSI (IRR = 1.99, 95% CrI: 1.39, 2.79) scores. OH-TEB and hydroxy-thiabendazole (metabolite of fungicide thiabendazole) combined contributed 54%, 40%, and 54% to the mixture effect in the anxiety symptoms, depression symptoms, and overall psychological distress models, respectively.

CONCLUSIONS

We found that exposure to tebuconazole and thiabendazole, fungicides whose effects have been rarely studied in humans, may be associated with increased psychological distress among avocado farmworkers. We also observed that exposure to chlorpyrifos may be associated with decreased psychological distress.

Housing Conditions and Health Implications for Migrant Agricultural Workers in Canada: A Scoping Review

Migrant agricultural workers face various health inequities that have led to preventable illness and death. This paper investigates how material housing conditions have shaped physical and mental health outcomes for temporary foreign workers in Canadian agriculture. We conducted a scoping review of literature on migrant agricultural worker housing in Canada published between 2000-2022, analysing insights on the physical quality of workers' housing in relation to international frameworks on housing quality. Our review revealed a range of housing-related health risks, including: (1) Sanitation, food security, and water; (2) Thermal safety, electricity, and utilities; (3) Habitability of structure, air quality, and exposure to hazards; (4) Spacing, privacy, and co-worker relations and; (5) Geographic proximity to necessary services and social opportunities. Although housing has been increasingly recognized as a social determinant of health, little research examines how migrant farmworkers' accommodations shape their health outcomes, particularly in Canada. This scoping review provides timely insights and recommendations to inform research, policy, and public health interventions.

Vulnerability of the Hippocampus to Insults: Links to Blood-Brain Barrier Dysfunction

The hippocampus is a critical brain substrate for learning and memory; events that harm the hippocampus can seriously impair mental and behavioral functioning. Hippocampal pathophysiologies have been identified as potential causes and effects of a remarkably diverse array of medical diseases, psychological disorders, and environmental sources of damage. It may be that the hippocampus is more vulnerable than other brain areas to insults that are related to these conditions. One purpose of this review is to assess the vulnerability of the hippocampus to the most prevalent types of insults in multiple biomedical domains (i.e., neuroactive pathogens, neurotoxins, neurological conditions, trauma, aging, neurodegenerative disease, acquired brain injury, mental health conditions, endocrine disorders, developmental disabilities, nutrition) and to evaluate whether these insults affect the hippocampus first and more prominently compared to other brain loci. A second purpose is to consider the role of hippocampal blood-brain barrier (BBB) breakdown in either causing or worsening the harmful effects of each insult. Recent research suggests that the hippocampal BBB is more fragile compared to other brain areas and may also be more prone to the disruption of the transport mechanisms that act to maintain the internal milieu. Moreover, a compromised BBB could be a factor that is common to many different types of insults. Our analysis indicates that the hippocampus is more vulnerable to insults compared to other parts of the brain, and that developing interventions that protect the hippocampal BBB may help to prevent or ameliorate the harmful effects of many insults on memory and cognition.

Investigating the prevalence of erectile dysfunction among men exposed to organophosphate insecticides

INTRODUCTION

Erectile dysfunction (ED) poses a significant disease morbidity and contributor to male infertility, where an estimated 20-40% of men are affected annually. While several risk factors have been identified in the etiology of ED (e.g., aging, heart disease, diabetes, and obesity), the complete pathogenesis remains to be elucidated. Over the last few decades, the contribution of environmental exposures to the pathogenesis of ED has gained some attention, though population studies are limited and results are mixed. Among environmental contaminants, organophosphate (OP) insecticides represent one of the largest chemical classes, and chlorpyrifos is the most commonly used OP in the U.S. OP exposure has been implicated in driving biological processes, including inflammation, reactive oxygen species production, and endocrine and metabolism disruption, which have been demonstrated to adversely affect the hypothalamus and testes and may contribute to ED. Currently, studies evaluating the association between OPs and ED within the U.S. general population are sparse.

METHODS

Data were leveraged from the National Health and Nutrition Examination Survey (NHANES), which is an annually conducted, population-based cross-sectional study. Urinary levels of 3,5,6-trichloro-2-pyridinol (TCPy), a specific metabolite of the most pervasive OP insecticide chlorpyrifos, were quantified as measures of OP exposure. ED was defined by responses to questionnaire data, where individuals who replied "sometimes able" or "never able" to achieve an erection were classified as ED. Chi-square, analysis of variance (ANOVA), and multivariable, weighted linear and logistic regression analyses were used to compare sociodemographic variables between quartiles of TCPy exposure, identify risk factors for TCPy exposure and ED, and to analyze the relationship between TCPy and ED.

RESULTS

A total of 671 adult men were included in final analyses, representing 28,949,379 adults after survey weighting. Approximately 37% of our cohort had ED. Smoking, diabetes, aging, Mexican-American self-identification, and physical inactivity were associated with higher ED prevalence. Analysis of TCPy modeled as a continuous variable revealed nonsignificant associations with ED (OR = 1.02 95% CI [0.95, 1.09]). Stratification of total TCPy into quartiles revealed increased odds of ED among adults in the second and fourth quartiles, using the first quartile as the reference (OR = 2.04 95% CI [1.11, 3.72], OR = 1.51 95% CI [0.58, 3.93], OR = 2.62 95% CI [1.18, 5.79], for quartiles 2, 3, and 4, respectively).

CONCLUSIONS

The results of our study suggest a potential role for chlorpyrifos and other OPs the pathogenesis of ED. Future studies are warranted to validate these findings, determine clinical significance, and to investigate potential mechanisms underlying these associations.

Pupil size change in agricultural workers exposed to pesticides

CLINICAL RELEVANCE

Pupil size evaluation using clinical examination may be important for detecting and monitoring individuals at risk of neurotoxic effects from chemical exposure, as it may enable early intervention and the implementation of preventive measures.

BACKGROUND

This work aimed to investigate the association between pesticide exposure and pupil size. Pupil size is regulated by muscarinic and nicotinic receptors, and it is well-established that common pesticide chemicals disrupt this regulation.

METHODS

Twenty agricultural workers exposed to pesticides, and twenty participants not exposed, underwent visual screening, and pupil size evaluation under mesopic and photopic conditions. Additionally, signs of neurotoxicity and pesticide exposure in both groups were evaluated using the modified version of the neurotoxic symptoms questionnaire (Q16) and measuring cholinesterase (AChE) levels in blood, respectively.

RESULTS

Agricultural workers exposed to pesticides had a score indicating medium-high level of neurotoxicity (49.85 (SD ± 8.94)) which was significantly higher (t (36) = 7.659, p ≤ 0.0001) than non-exposed participants who had low levels of neurotoxicity (27.25 SD ± 8.86). There was a significant difference in pupil size (mm) under mesopic (t (19) 4.42 p = 0.003) and scotopic (t (19) 4.63, p = 0.0002) conditions between the two groups. Additionally, there was a significant difference in AChE blood levels (t (19) 2.94 p = 0.008) between exposed and non-exposed participants, indicating that exposed workers had low levels of this enzyme (average exposed group 3381 U/L (SD ± 1306)) compared to the non-exposed group (average non-exposed group 4765 U/L (SD ± 1300)). A significant negative correlation between AChE levels, years of exposure, and pupil size was found. The latter finding importantly showed that smaller pupils are associated with the accumulation of acetylcholine or a decrease in the activity of the enzyme AChE.

CONCLUSION

Pupil size of agricultural workers exposed to pesticides can be abnormal and is associated with neurotoxicity as indicated by symptomatology and cholinesterase levels. Evaluation of pupil size may be useful for clinically detecting neurotoxicity.

Associations between pesticide exposure with biomarkers of stroke risk factors in farmers

The extensive use of pesticides may cause acute and chronic intoxication. Therefore, this study aimed to reveal the associations between pesticide exposure and serum markers for stroke risk factors in farmers. A cross-sectional study was conducted with farmers, who used chemical pesticides in Seloprojo Village, Ngablak District, Magelang Regency, Central Java Province, Indonesia. A questionnaire containing demographics, pesticide use, and aspects related to work was employed. Measurements of serum cholesterol, uric acid, glucose, cholinesterase, and fibrinogen levels were also conducted. Of the 106 subjects, 31 (29.2%) used organophosphates as chemical pesticides. There was a significant difference between organophosphate and nonorganophosphate groups in plasma fibrinogen levels. The organophosphate group had higher levels of fibrinogen (292.29 ± 67.56 mg/dL) than the non-organophosphate group (255.24 ± 38.90 mg/dL). Of the studied risk factors for stroke, there is a significant association between organophosphate exposure and increased plasma fibrinogen levels.

Neuropathy caused by pesticide exposure on farmers in Ngablak District, Magelang, Central Java, Indonesia: An electroneuromyography study

Uncontrolled and unsafe use of pesticides can lead to acute and chronic toxicity in farmers, with neuropathy being one of the most common symptoms of chronic toxicity. However, the effects of this toxicity on farmers' electroneuromyography (ENMG) are still unclear. To address this, we conducted a cross-sectional study from July to October 2017 in Ngablak District, Magelang, Central Java, Indonesia. Eligible farmers who were exposed to pesticides underwent electrophysiology examinations, as well as additional tests such as physical examination and laboratory testing. We collected general information such as age and work history by interview. In total, 64 farmers were included in this study. Out of these, 44 farmers were found to have polyneuropathy, with 41 of them having motor polyneuropathy and 19 of them having sensory polyneuropathy. Our findings showed that low blood cholinesterase was associated with distal latency prolongation (p-value: 0.014). The group exposed to organophosphate/carbamate pesticides was also significantly associated with prolonged distal latency (p-value: 0.012). However, motor polyneuropathy was significantly associated with chronic exposure to organophosphate/carbamate pesticides (p-value: 0.009) and not with low blood cholinesterase levels (p-value: 0.454). The study concludes that chronic exposure to organophosphate or carbamate pesticides could result in polyneuropathy disease, particularly in the motor system.

Competitive Assay for the Ultrasensitive Detection of Organophosphate Pesticides Based on a Fiber-Optic Particle Plasmon Resonance Biosensor and an Acetylcholinesterase Binding Peptide

An acetylcholinesterase (AChE) binding-based biosensor was developed for the ultrasensitive detection of organophosphate (OP) pesticides. The biosensor integrates the technique based on fiber-optic particle plasmon resonance detection and a synthetic AChE binding peptide conjugated with gold nanoparticles on the optical fiber surface via an AChE competitive binding assay. The OP pesticides present in the solution hinder the binding of AChE to the peptide on the biosensor by competing for the binding sites present in AChE. The limit of detection obtained for parathion using this method was observed to be 0.66 ppt (2.3 pM). This method shows a wide linear dynamic range of 6 orders. Furthermore, the use of the AChE binding peptide in the biosensor can better discriminate OPs against carbamates by using only a single biosensor. The practical application of this method was tested using spiked samples, which yielded good recovery and reproducibility. The spiked sample required minimal pretreatment before analysis; hence, this biosensor may also be used in the field.

Contamination of herbal medicinal products in low-and-middle-income countries: A systematic review

The use of herbal medicinal products (HMPs) has grown significantly across low-and-middle-income countries (LMICs). Consequently, the safety of these products due to contamination is a significant public health concern. This systematic review aimed to determine the prevalence, types, and levels of contaminants in HMPs from LMICs. A search was performed in seven online databases, i.e., Africa journal online (AJOL), Cumulative Index to Nursing and Allied Health Literature (CINAHL), Directory of Open Access Journals (DOAJ), Health Inter-Network Access to Research Initiative (HINARI), World Health Organization Global Index Medicus (WHO GIM), Scopus, and PubMed using appropriate search queries and reported as per the "Preferred Reporting Items for Systematic Reviews and Meta-Analyses" (PRISMA) guidelines. Ninety-one peer-reviewed articles published from 1982 to 2021 from 28 different countries across four continents were included in the study. Although metals, microbial, mycotoxins, pesticides, and residual solvents were the reported contaminants in the 91 articles, metals (56.0%, 51/91), microbial (27.5%, 25/91), and mycotoxins (18.7%, 17/91) were the most predominant. About 16.4% (1236/7518) of the samples had their contaminant levels above the regulatory limits. Samples tested for microbial contaminants had the highest proportion (46.4%, 482/1039) of contaminants exceeding the regulatory limit, followed by mycotoxins (25.8%, 109/423) and metals (14.3%, 591/4128). The proportion of samples that had their average non-essential metal contaminant levels above the regulatory limit was (57.6%, 377/655), 18.3% (88/480), 10.7% (24/225), and 11.3% (29/257) for Pb, Cd, Hg, and As, respectively. The commonest bacteria species found were Escherichia coli (52.3%, 10/19) and Salmonella species (42.1%, 8/19). This review reported that almost 90% of Candida albicans and more than 80% of moulds exceeded the required regulatory limits. HMP consumption poses profound health implications to consumers and patients. Therefore, designing and/or implementing policies that effectively regulate HMPs to minimize the health hazards related to their consumption while improving the quality of life of persons living in LMICs are urgently needed.

Occupational exposure to pesticides and symptoms of depression in agricultural workers. A systematic review

BACKGROUND

The use of pesticides can result in harm to both the environment and human health. There is a growing concern in the field of occupational health about the impact on the mental health of agricultural workers.

OBJECTIVES

The objective of this review was to systematize scientific evidence from the last ten years on the impact of occupational exposure to pesticides on the development of depression symptoms in agricultural workers.

METHODS

We conducted a comprehensive search in the PubMed and Scopus databases from 2011 to September 2022. Our search included studies in English, Spanish, and Portuguese that examined the association between occupational exposure to pesticides and symptoms of depression in agricultural workers, following the guidelines recommended by the PRISMA statement and the PECO strategy (Population, Exposure, Comparison, and Outcomes).

RESULTS

Among the 27 articles reviewed, 78% of them indicated a link between exposure to pesticides and the incidence of depression symptoms. The pesticides most frequently reported in the studies were organophosphates (17 studies), herbicides (12 studies), and pyrethroids (11 studies). The majority of the studies were rated as having intermediate to intermediate-high quality, with the use of standardized measures to assess both exposure and effect.

CONCLUSION

The updated evidence presented in our review indicates a clear association between pesticide exposure and the development of depressive symptoms. However, more high-quality longitudinal studies are necessary to control for sociocultural variables and utilize pesticide-specific biomarkers and biomarkers of depression. Given the increased use of these chemicals and the health risks associated with depression, it is crucial to implement more stringent measures to monitor the mental health of agricultural workers regularly exposed to pesticides and to enhance surveillance of companies that apply these chemicals.

Mapping Potential Population-Level Pesticide Exposures in Ecuador Using a Modular and Scalable Geospatial Strategy

Human populations and ecosystems are extensively exposed to pesticides. Most nations lack the capacity to control pesticide contamination and have limited availability of pesticide use information. Ecuador is a country with intense pesticide use with high exposure risks to humans and the environment, although relative or combined risks are not well understood. Here, we analyzed the distribution of application rates in Ecuador and identified regions of concern because of high potential exposure. We used a geospatial analysis to identify grid cells (∼8 km × 8 km) where the highest pesticide application rates and density of human populations overlap. Furthermore, we identified other regions of concern based on the number of amphibian species as an indicator of ecosystem integrity and the location of natural protected areas. We found that 28% of Ecuador's population dwelled in areas with high pesticide application rate. We identified an area of ∼512 km2 in the Amazon region where high application rates, large human settlements, and a high number of amphibian species overlapped. Additionally, we distinguished clusters of pesticide application rates and human populations that intersected with natural protected areas. Ecuador exemplifies how pesticides are disproportionately applied in areas with the potential to affect human health and ecosystems' integrity. Global estimates of population dwelling, pesticide application rates, and environmental factors are key in prioritizing locations to conduct further exposure assessments. The modular and scalable nature of the geospatial tools we developed can be expanded and adapted to other regions of the world where data on pesticide use are limited.

Association of Pesticide Exposure with Cognitive Function in Farmers

INTRODUCTION

Organophosphate and carbamate are two types of pesticides that can induce cholinesterase suppression in humans. These lead to poisoning symptoms including muscle paralysis and respiratory depression in acute settings. In chronic settings, the mechanism of organophosphate and carbamate poisoning is still openly discussed. Accordingly, this study aimed to identify any correlations between erythrocyte cholinesterase and type of pesticides with cognitive performance of the subjects.

METHODS

This cross-sectional study was conducted in two sampling periods (July 2017 and October 2018) in Ngablak Districts, Magelang Regency, Central Java, Indonesia. The study subjects were farmers with history of pesticide exposure. Cholinesterase levels (ChE) were analyzed from blood samples. Cognitive performance was assessed using the Mini Mental State Examination (MMSE) and Stroop Test.

RESULTS

In total, 151 subjects aged between 23 and 91 years old were included. The long-term organophosphate exposure group had significantly lower MMSE scores compared with other types of pesticides, but not in carbamate (p = 0.017). After comparing "organophosphate only" and "carbamate only" groups, there were significant differences in MMSE scores (p = 0.018) but not in blood ChE levels (p = 0.286). Detailed assessment in MMSE domains showed significantly lower scores for orientation, attention, and registration domains (p < 0.05) in the organophosphate group. There were no significant associations between types of pesticides and blood ChE levels with the Stroop Test results (p > 0.05).

CONCLUSIONS

Long-term organophosphate exposure could produce lower cognitive function and the insignificant association between blood ChE levels to MMSE could lead to non-cholinergic pathways as its underlying pathology.

Cognitive and Cellular Effects of Combined Organophosphate Toxicity and Mild Traumatic Brain Injury

Traumatic brain injury (TBI) is considered the most common neurological disorder among people under the age of 50. In modern combat zones, a combination of TBI and organophosphates (OP) can cause both fatal and long-term effects on the brain. We utilized a mouse closed-head TBI model induced by a weight drop device, along with OP exposure to paraoxon. Spatial and visual memory as well as neuron loss and reactive astrocytosis were measured 30 days after exposure to mild TBI (mTBI) and/or paraoxon. Molecular and cellular changes were assessed in the temporal cortex and hippocampus. Cognitive and behavioral deficits were most pronounced in animals that received a combination of paraoxon exposure and mTBI, suggesting an additive effect of the insults. Neuron survival was reduced in proximity to the injury site after exposure to paraoxon with or without mTBI, whereas in the dentate gyrus hilus, cell survival was only reduced in mice exposed to paraoxon prior to sustaining a mTBI. Neuroinflammation was increased in the dentate gyrus in all groups exposed to mTBI and/or to paraoxon. Astrocyte morphology was significantly changed in mice exposed to paraoxon prior to sustaining an mTBI. These results provide further support for assumptions concerning the effects of OP exposure following the Gulf War. This study reveals additional insights into the potentially additive effects of OP exposure and mTBI, which may result in more severe brain damage on the modern battlefield.

Relationship between Butyrylcholinesterase Activity and Cognitive Ability in Workers Exposed to Chlorpyrifos

Background. The use of Chlorpyrifos leads to a public, environmental, and occupational health problem associated with adverse effects in the exposed population, generating alterations mainly in the central nervous system, such as cognitive function. This study aimed to estimate the association between butyrylcholinesterase activity (BChE) and cognitive ability in workers exposed to chlorpyrifos. Methods. We designed a cross-sectional study, where we measured BChE in serum samples as an indicator of exposure to chlorpyrifos. The cognitive ability was assessed by the mean score of the Peruvian version of the Mini-Mental State Examination (MMSE). We also used a questionary to collect demographic and occupational information. Results. We evaluated 120 farmers with a predominance of males (92%) and a mean age of 32.1 ± 9.0 years. We found most of the workers in fumigation activities (84%). The mean BChE was 6144.7 ± 2355.0 U/L, and 46% presented inhibition enzyme (<5500 U/L). The median MMSE score was 28 (interquartile range: 26.5–31.5; 6% showed an alteration in cognitive ability (score < 24)). The MMSE test found a significant association between BChE inhibition and MMSE score (β: −0.071, 95%CI: −0.108 to −0.025). Conclusion. In this study, 45.8% of workers exposed to chlorpyriphos presented BChE inhibition. The BChE inhibition is significantly associated with the MMSE score in workers exposed to chlorpyrifos.

Assessment of risks, implications, and opportunities of waterborne neurotoxic pesticides

Pesticides are a well-known family of chemicals that have contaminated water systems globally. Four common subfamilies of pesticides include organochlorines, organophosphates, pyrethroids, and carbamate insecticides which have been shown to adversely affect the human nervous system. Studies have shown a link between pesticide exposure and decreased viability, proliferation, migration, and differentiation of murine neural stem cells. Besides human exposure directly through water systems, additional factors such as pesticide bioaccumulation, biomagnification and potential synergism due to co-exposure to other environmental contaminants must be considered. A possible avenue to investigate the molecular mechanisms and biomolecules impacted by the various classes of pesticides includes the field of -omics. Discovery of the precise molecular mechanisms behind pesticide-mediated neurodegenerative disorders may facilitate development of targeted therapeutics. Likewise, discovery of pesticide biodegradation pathways may enable novel approaches for water system bioremediation using genetically engineered microorganisms. In this mini-review, we discuss recently established harmful impacts of various categories of pesticides on the nervous system and the application of -omics field for discovery, validation, and mitigation of pesticide neurotoxicity.

Associations of single and multiple organophosphate pesticide exposure with female infertility in the USA: data from the 2015-2018 National Health and Nutrition Examination Survey

Substantial evidence has shown that organophosphate pesticide (OPP) exposure altered the reproductive system functions, such as prolonged menstrual cycles, sexual hormone imbalance, and changes in ovarian weight. However, the association of OPP exposure with female infertility is unclear. We explored the relationships of four single OPP metabolites and their mixed exposure with self-reported infertility among women aged 20-50 in the USA using the data from two cycles (2015-2016 and 2017-2018) of the National Health and Nutrition Examination Survey (NHANES) by multiple logistic regression, Bayesian kernel machine regression (BKMR), and quantile g-computation (QGC). Eventually, 659 females were included in our study. Among these females, 77 participants were ever infertile. Multiple logistic regression showed that the odds ratios (ORs) in the second and third tertiles of dimethylphosphate (DMP) for female infertility were 2.53 (95% confidence interval (95%CI): 1.20-5.32, P value = 0.016) and 2.96 (95%CI: 1.18-7.47, P value = 0.023) compared to the lowest tertile after adjusting for all covariates (P for trend = 0.022). A significantly positive association between the mixed OPP metabolites and infertility was observed in the BKMR model, in which DMP had the highest posterior inclusion probability (PIP = 0.741). The QGC model showed similar results, in which OPP metabolite mixtures increased the risk of female infertility, with DMP as a significantly positive contributor to the outcome. This study revealed the potential harm of OPP mixtures for female infertility in the USA, and DMP played the most critical role in female infertility risk among all OPP metabolites.

Multiple neurological effects associated with exposure to organophosphorus pesticides in man

This article reviews available data regarding the possible association of organophosphorus (OP) pesticides with neurological disorders such as dementia, attention deficit hyperactivity disorder, neurodevelopment, autism, cognitive development, Parkinson's disease and chronic organophosphate-induced neuropsychiatric disorder. These effects mainly develop after repeated (chronic) human exposure to low doses of OP. In addition, three well defined neurotoxic effects in humans caused by single doses of OP compounds are discussed. Those effects are the cholinergic syndrome, the intermediate syndrome and organophosphate-induced delayed polyneuropathy. Usually, the poisoning can be avoided by an improved administrative control, limited access to OP pesticides, efficient measures of personal protection and education of OP pesticide applicators and medical staff.

Pesticide exposure and cortical brain activation among farmworkers in Costa Rica

BACKGROUND

Previous epidemiological studies have reported associations of pesticide exposure with poor cognitive function and behavioral problems. However, these findings have relied primarily on neuropsychological assessments. Questions remain about the neurobiological effects of pesticide exposure, specifically where in the brain pesticides exert their effects and whether compensatory mechanisms in the brain may have masked pesticide-related associations in studies that relied purely on neuropsychological measures.

METHODS

We conducted a functional neuroimaging study in 48 farmworkers from Zarcero County, Costa Rica, in 2016. We measured concentrations of 13 insecticide, fungicide, or herbicide metabolites or parent compounds in urine samples collected during two study visits (approximately 3-5 weeks apart). We assessed cortical brain activation in the prefrontal cortex during tasks of working memory, attention, and cognitive flexibility using functional near-infrared spectroscopy (fNIRS). We estimated associations of pesticide exposure with cortical brain activation using multivariable linear regression models adjusted for age and education level.

RESULTS

We found that higher concentrations of insecticide metabolites were associated with reduced activation in the prefrontal cortex during a working memory task. For example, 3,5,6-trichloro-2-pyridinol (TCPy; a metabolite of the organophosphate chlorpyrifos) was associated with reduced activation in the left dorsolateral prefrontal cortex (β = -2.3; 95% CI: -3.9, -0.7 per two-fold increase in TCPy). Similarly, 3-phenoxybenzoic acid (3-PBA; a metabolite of pyrethroid insecticides) was associated with bilateral reduced activation in the dorsolateral prefrontal cortices (β = -3.1; 95% CI: -5.0, -1.2 and -2.3; 95% CI: -4.5, -0.2 per two-fold increase in 3-PBA for left and right cortices, respectively). These associations were similar, though weaker, for the attention and cognitive flexibility tasks. We observed null associations of fungicide and herbicide biomarker concentrations with cortical brain activation during the three tasks that were administered.

CONCLUSION

Our findings suggest that organophosphate and pyrethroid insecticides may impact cortical brain activation in the prefrontal cortex - neural dynamics that could potentially underlie previously reported associations with cognitive and behavioral function. Furthermore, our study demonstrates the feasibility and utility of fNIRS in epidemiological field studies.

Exposure to organophosphate insecticides, inappropriate personal protective equipment use, and cognitive performance among pesticide applicators

Inappropriate use of personal protective equipment (PPE) among pesticide applicators may increase urinary organophosphate (OP) metabolite levels and subsequently increase risks of cognitive performance. Therefore, this study aims to (1) compare urinary OP metabolite levels and cognitive performance between pre-and post-pesticide application seasons; (2) PPE use and factors associated with PPE use linked to increased urinary OP metabolite levels during pesticide application; and (3) the association between urinary OP metabolite levels and cognitive performance. This longitudinal follow-up study on 79 pesticide applicators was carried out between October 2021 and January 2022. The applicators were interviewed, collected urine samples, and tested for cognitive performance in pre-and post-pesticide application seasons. The results found that the levels of urinary OP metabolites in post-application season were significantly higher than those in pre-application season (p < 0.001). Multiple linear regression analysis found that increased total diethylphosphate (DEP) and total dialkylphosphate (DAP) levels were associated with not wearing gloves while mixing pesticides [beta (β) ± standard error (SE) = -43.74 ± 18.52, 95% confidence interval (95% CI) = -80.84, -6.64 for total DEP and -50.84 ± 19.26, 95% CI = -89.41, -12.26 for total DAP] and also with not wearing a mask while spraying pesticides (β ± SE = -31.76 ± 12.24, 95% CI = -56.28, -7.24 for total DEP and -33.20 ± 12.63, 95% CI = -58.49, -7.92 for total DAP) after adjusting for covariates. The scores of Montreal Cognitive Assessment-Thai, Thai Mental State Examination, and Mini-Cognitive test in post-pesticide application were significantly lower than those in pre-pesticide application (p < 0.001). However, no association was found between urinary OP metabolite levels and cognitive decline. Our findings indicate that inappropriate PPE use during pesticide application was the major factor affecting urinary OP metabolite levels among pesticide applicators. Wearing gloves when mixing pesticides and a mask when spraying pesticides were key factors in reducing occupational exposure to OP. Exposure to OP at low levels and for short periods of exposure may not affect cognitive performance significantly. Therefore, long-term exposure and exposure to high levels of OP should be investigated further.

Molecular and Cellular Interactions in Pathogenesis of Sporadic Parkinson Disease

An increasing number of the population all around the world suffer from age-associated neurodegenerative diseases including Parkinson’s disease (PD). This disorder presents different signs of genetic, epigenetic and environmental origin, and molecular, cellular and intracellular dysfunction. At the molecular level, α-synuclein (αSyn) was identified as the principal molecule constituting the Lewy bodies (LB). The gut microbiota participates in the pathogenesis of PD and may contribute to the loss of dopaminergic neurons through mitochondrial dysfunction. The most important pathogenetic link is an imbalance of Ca²⁺ ions, which is associated with redox imbalance in the cells and increased generation of reactive oxygen species (ROS). In this review, genetic, epigenetic and environmental factors that cause these disorders and their cause-and-effect relationships are considered. As a constituent of environmental factors, the example of organophosphates (OPs) is also reviewed. The role of endothelial damage in the pathogenesis of PD is discussed, and a ‘triple hit hypothesis’ is proposed as a modification of Braak’s dual hit one. In the absence of effective therapies for neurodegenerative diseases, more and more evidence is emerging about the positive impact of nutritional structure and healthy lifestyle on the state of blood vessels and the risk of developing these diseases.

Health Effects of Pesticide Exposure in Latin American and the Caribbean Populations: A Scoping Review

BACKGROUND

Multiple epidemiological studies have shown that exposure to pesticides is associated with adverse health outcomes. However, the literature on pesticide-related health effects in the Latin American and the Caribbean (LAC) region, an area of intensive agricultural and residential pesticide use, is sparse. We conducted a scoping review to describe the current state of research on the health effects of pesticide exposure in LAC populations with the goal of identifying knowledge gaps and research capacity building needs.

METHODS

We searched PubMed and SciELO for epidemiological studies on pesticide exposure and human health in LAC populations published between January 2007 and December 2021. We identified 233 publications from 16 countries that met our inclusion criteria and grouped them by health outcome (genotoxicity, neurobehavioral outcomes, placental outcomes and teratogenicity, cancer, thyroid function, reproductive outcomes, birth outcomes and child growth, and others).

RESULTS

Most published studies were conducted in Brazil (37%, n = 88 ) and Mexico (20%, n = 46 ), were cross-sectional in design (72%, n = 167 ), and focused on farmworkers (45%, n = 105 ) or children (21%, n = 48 ). The most frequently studied health effects included genotoxicity (24%, n = 62 ) and neurobehavioral outcomes (21%, n = 54 ), and organophosphate (OP) pesticides were the most frequently examined (26%, n = 81 ). Forty-seven percent (n = 112 ) of the studies relied only on indirect pesticide exposure assessment methods. Exposure to OP pesticides, carbamates, or to multiple pesticide classes was consistently associated with markers of genotoxicity and adverse neurobehavioral outcomes, particularly among children and farmworkers.

DISCUSSION

Our scoping review provides some evidence that exposure to pesticides may adversely impact the health of LAC populations, but methodological limitations and inconsistencies undermine the strength of the conclusions. It is critical to increase capacity building, integrate research initiatives, and conduct more rigorous epidemiological studies in the region to address these limitations, better inform public health surveillance systems, and maximize the impact of research on public policies. https://doi.org/10.1289/EHP9934.

Environmental and human health at risk - Scenarios to achieve the Farm to Fork 50% pesticide reduction goals

The recently released Farm to Fork Strategy of the European Union sets, for the first time, pesticide reduction goals at the EU level: 50% reduction in overall use and risk of chemical pesticides and a 50% use reduction of more hazardous pesticides. However, there is little guidance provided as to how to achieve these targets. In this study, we compiled the characteristics of all 230 EU-approved, synthetic, open-field use active substances (AS) used as herbicides, fungicides and insecticides, and explored the potential of seven Farm to Fork-inspired pesticide use reduction scenarios to achieve the 50% reduction goals. The pesticide reduction scenarios were based on recommended AS application rates, pesticide type, soil persistence, presence on the candidate for substitution list, and hazard to humans and ecosystems. All 230 AS have been found to cause negative effects on humans or ecosystems depending on exposure levels. This is found despite the incomplete hazard profiles of several AS. 'No data available' situations are often observed for the same endpoints and specific organisms. The results of the scenarios indicate that only severe pesticide use restrictions, such as allowing only low-hazard substances, will result in the targeted 50% use and risk reductions. Over half of the 230 AS considered are top use or top hazard substances, however, the reduction actions depend on the still to be defined EC priority areas and action plans, also for other recent and related strategies. Broader scenario implications (on productivity, biodiversity or economy) and the response of farmers to the pesticide use restrictions should be explored in those plans to define effective actions. Our results emphasize the need for a re-evaluation of the approved AS and of their representative uses, and the call for open access to AS, crop and region-specific use data to refine scenarios and assess effective reductions.

Association between pesticide exposure and neurobehavioral performance of agricultural workers: A cross-sectional study

BACKGROUND

Pesticide exposure has affected humans' health, especially those directly in contact with a pesticide like agricultural workers. Here, we sought to see a link between pesticide exposure and cognitive impairment among male agricultural workers.

METHODS

We selected 18-60 years old 100 male agricultural workers who came for their health check-up in the hospital's out-patient department from August 2020 to May 2021. Standardized questionnaires (German Q18 questionnaire) and WHO Neurobehavioral Core Test Battery were used to examine the neurobehavioral performance of the individuals. The data were presented in a descriptive manner and statistically examined using the chi-square test.

RESULTS

The male agricultural workers' neurobehavioral performance was 46% normal and 54% abnormal. Headaches, impaired focus, short memory, weariness, palpitation, and numbness were the most prevalent neurobehavioral impairments. The chi-square test revealed that spraying frequency (p =.010), personal protective equipment (PPE) use (p < .001), and smoking habits (p =.006) were all linked to neurobehavioral performance, while spraying duration (p =.804), working years (p =.234), pesticide types (p =.816), and spraying time (p =.867) were not linked to neurobehavioral performance.

CONCLUSION

We found that pesticide exposure has a certain role on neurobehavioral performance in adult male agricultural workers as more people have been affected; however, a considerable number of confounding factors might have played a significant role in giving rise to such results. The government should be concerned about farmer's neurobehavioral performance and implement different approaches to minimize the use of pesticides so that agricultural workers can work without any mental health problems.

Altered Default Mode Network Associated with Pesticide Exposure in Latinx Children from Rural Farmworker Families

Pesticide exposure has been associated with adverse cognitive and neurological effects. However, neuroimaging studies aimed at examining the impacts of pesticide exposure on brain networks underlying abnormal neurodevelopment in children remain limited. It has been demonstrated that pesticide exposure in children is associated with disrupted brain anatomy in regions that make up the default mode network (DMN), a subnetwork engaged across a diverse set of cognitive processes, particularly higher-order cognitive tasks. This study tested the hypothesis that functional brain network connectivity/topology in Latinx children from rural farmworker families (FW children) would differ from urban Latinx children from non-farmworker families (NFW children). We also tested the hypothesis that probable historic childhood exposure to pesticides among FW children would be associated with network connectivity/topology in a manner that parallels differences between FW and NFW children. We used brain networks from functional magnetic resonance imaging (fMRI) data from 78 children and a mixed-effects regression framework to test our hypotheses. We found that network topology was differently associated with the connection probability between FW and NFW children in the DMN. Our results also indicated that, among 48 FW children, historic reports of exposure to pesticides from prenatal to 96 months old were significantly associated with DMN topology, as hypothesized. Although the cause of the differences in brain networks between FW and NFW children cannot be determined using a cross-sectional study design, the observed associations between network connectivity/topology and historic exposure reports in FW children provide compelling evidence for a contribution of pesticide exposure on altering the DMN network organization in this vulnerable population. Although longitudinal follow-up of the children is necessary to further elucidate the cause and reveal the ultimate neurological implications, these findings raise serious concerns about the potential adverse health consequences from developmental neurotoxicity associated with pesticide exposure in this vulnerable population.

Food Contamination: An Unexplored Possible Link between Dietary Habits and Parkinson’s Disease

Importance of a healthy lifestyle in maintaining the population’s well-being and health, especially in terms of balanced nutrition, is well known. Food choice of and dieting habits could impact disease management, which is especially true for Parkinson’s disease (PD). However, nowadays, it is not that simple to maintain a balance in nutrition, and the idea of a healthy diet tends to fade as the consequence of a western lifestyle. This should not only be dealt with in the context of food choice, but also from an environmental point of view. What we put into our bodies is strictly related to the quality of ecosystems we live in. For these reasons, attention should be directed to all the pollutants, which in many cases, we unknowingly ingest. It will be necessary to explore the interaction between food and environment, since human activity also influences the raw materials destined for consumption. This awareness can be achieved by means of an innovative scientific approach, which involves the use of new models, in order to overcome the traditional scientific investigations included in the study of Parkinson’s disease.

Risk Factors for Brain Health in Agricultural Work: A Systematic Review

Certain exposures related to agricultural work have been associated with neurological disorders. To date, few studies have included brain health measurements to link specific risk factors with possible neural mechanisms. Moreover, a synthesis of agricultural risk factors associated with poorer brain health outcomes is missing. In this systematic review, we identified 106 articles using keywords related to agriculture, occupational exposure, and the brain. We identified seven major risk factors: non-specific factors that are associated with agricultural work itself, toluene, pesticides, heavy metal or dust exposure, work with farm animals, and nicotine exposure from plants. Of these, pesticides are the most highly studied. The majority of qualifying studies were epidemiological studies. Nigral striatal regions were the most well studied brain area impacted. Of the three human neuroimaging studies we found, two focused on functional networks and the third focused on gray matter. We identified two major directions for future studies that will help inform preventative strategies for brain health in vulnerable agricultural workers: (1) the effects of moderators such as type of work, sex, migrant status, race, and age; and (2) more comprehensive brain imaging studies, both observational and experimental, involving several imaging techniques.

Breathing-Focused Yoga Intervention on Respiratory Decline in Chronically Pesticide-Exposed Farmers: A Randomized Controlled Trial

Background

Occupational exposure to pesticides has been associated with lung and cognitive function exacerbations. In the present study, we tested the effectiveness of breathing focused yoga intervention on alleviation of adverse respiratory and cognitive effects associated with chronic pesticide exposure in farmers.

Methods

We undertook a parallel, two-armed randomized controlled trial with blinded outcome assessors on a chronically pesticide-exposed farming population. The study was conducted at district Panipat, State Haryana located in the Northern part of India from November 2019 to August 2020. A total of 634 farmers were screened, and 140 farmers were randomized to breathing-focused yoga intervention (BFY, n = 70) and waitlist control arms (n = 65). BFY was delivered weekly in 45-min group sessions over 12 weeks followed by home-based practice. The primary outcome was the change in spirometry-based markers of pulmonary function from baseline expressed as raw values, Global Lung Initiative (GLI) percent predicted (pp), and GLI z-scores after 24 weeks of intervention. Secondary variables were Trail making tests (TMT A and B), Digit symbol substitution (DSST), and WHO Quality of life-BREF (WHOQOL-Bref). Analysis was by intention-to-treat. Mediation analysis was done considering oxidative stress markers as potential mediators.

Results

At the end of 6 months of intervention, the overall follow-up in the participants was 87.85% (n = 123); 90% (n = 63) in the control group, and 85.71% in the yoga group (n = 60). The mean age of the study cohort (n = 140) was 38.75 (SD = 7.50) years. Compared with the control group, at 24 weeks post-intervention, the BFY group had significantly improved status of the raw sand z scores markers of airway obstruction, after adjusting for confounders, FEV1, FVC, FEF25-75 [z score-adjusted mean differences (95% CI); 1.66 (1.10-2.21) 1.88 (1.21-2.55), and 6.85 (5.12-8.57), respectively. A fraction of FEF25-75 change (mediation percentage 23.95%) was explained by glutathione augmentation. There were also significant improvements in cognitive scores of DSST, TMT-A and TMT-B, and WHOQOL-Bref.

Conclusion

In conclusion, regular practice of BFY could improve the exacerbations in the markers of airway obstruction in chronically pesticide-exposed farmers and cognitive variables. A significant mediating effect of glutathione augmentation was also observed concerning the effect of the intervention on FEF25-75. These findings provide an important piece of beneficial evidence of the breathing-based yoga intervention that needs validation across different farming ethnicities.Clinical Trial Registration:www.ClinicalTrials.gov, identifier: CTRI/2019/11/021989.

Investigation of Prenatal Pesticide Exposure and Neurodevelopmental Deficits in Northern Thailand: Protocol for a Longitudinal Birth Cohort Study

BACKGROUND

Prenatal exposure to pesticides has been linked to adverse neurodevelopmental outcomes. Gaps exist in the current literature about the timing and magnitude of exposures that result in these adverse outcomes.

OBJECTIVE

The Study of Asian Women and their Offspring's Development and Environmental Exposures (SAWASDEE) cohort was established to investigate the impact of prenatal exposure to pesticides on early indicators of cognitive and motor skills, inhibitory control, emotion regulation, and memory that have been found to be important in the development of subsequent neurobehavioral and neurodevelopmental diseases. The overarching goal is to find earlier predictors of potential adverse neurologic outcomes in order to enable earlier interventions that could result in better outcome prognoses.

METHODS

Recruitment of this prospective, longitudinal birth cohort began in July 2017 and was completed in June 2019 in Chom Thong and Fang, 2 farming districts in Chiang Mai Province in northern Thailand. Follow-up of the study participants is ongoing. During pregnancy, 7 questionnaires were administered. Time-resolved biospecimen samples were collected monthly (for urine) and during each trimester (for blood) during antenatal care visits. Medical records were abstracted. Infants were administered the NICU Network Neurobehavioral Scale (NNNS) test at 1 month of age. A total of 322 mother-child pairs completed the NNNS test. All children will be followed until 3 years of age and undergo a series of neurodevelopmental tests. We will complete several additional exposure related analyses.

RESULTS

A total of 1298 women were screened, and of those, 394 (30.35%) women were enrolled. The mean gestational age at enrollment was 9.9 weeks (SD 2.6). Differences in literacy were observed between Chom Thong and Fang participants. In Fang, about 54 of 105 (51.4%) participants reported being able to read in Thai compared to about 206 of 217 (94.9%) participants in Chom Thong. The percentages were comparable for reporting to be able to write in Thai.

CONCLUSIONS

This longitudinal birth cohort study will inform risk assessment standards for pregnant women in Thailand and other countries. Building awareness of how insecticide exposure during specific windows of pregnancy affects the neurodevelopmental trajectories of children in developing countries is a specific need recognized by the World Health Organization.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/31696.

Prevalence of Pesticide Use and Occupational Exposure Among Small-Scale Farmers in Western Ethiopia

OBJECTIVE

This study aims to assess the prevalence of pesticide use and its occupational exposure among small-scale farmers in the Kellem Wellega Zone of western Ethiopia.

METHODS

A cross-sectional study design using a structured questionnaire was used to collect data from 249 small-scale farmers' households through face-to-face interviews. Statistical analysis such as descriptive statistics, Chi-square test, and binary logistic regression analysis was applied, and a P-value <.05 at 95% CI was considered statistically significant.

RESULTS

The prevalence of pesticide use was 87.15%. About 44.2%, 40.2%, and 43.8% of the study participants were classified as having poor knowledge, poor practice, and negative attitude toward pesticide use, respectively. Thus, small-scale farmers whose age was greater than 40 years were 7.87 times more likely to be exposed to skin irritation than those whose age was less than 20 years (AOR = 7.87; 95% CI: 1.75-35.45) and skin contact (AOR = 0.37; 95% CI: 0.15-0.91). Most farmers who were directly involved in agriculture were 2.22 times more likely to be exposed to the inhalation of pesticide chemicals than those involved in another activity (AOR = 2.22; 95% CI: 1.14-4.33). Based on educational level, small-scale farmers who have a primary school and above were 81% less likely to inhale pesticide chemicals than those who did not have formal education (AOR = 0.19; 95% CI: 0.09-0.41). Furthermore, low-income small-scale farmers were 2.62 times more likely to be exposed to coughing (AOR = 2.62; 95% CI: 1.25-5.51) than high-income participants. Furthermore, farmers with good knowledge were 1.79 times more likely to be exposed to skin irritation than those with poor knowledge (AOR = 1.79; 95% CI: 1.0-3.17). Farmers with poor practice were 1.85 times more likely to show coughing symptoms than those with good practice (AOR = 1.85; 95% CI: 1.08-3.2), and farmers with good practice were 48% less likely to be exposed to headache than those with poor practice (AOR = 0.52; 95% CI: 0.31-0.88).

CONCLUSIONS

This study shows that small-scale farmers were exposed to pesticides through coughing, headache, skin irritation, inhalation, and skin contact. Low level of knowledge, poor practice, job, low income, older age, and educational level.

A Double-Site Chemodosimeter for Selective Fluorescence Detection of a Nerve Agent Mimic

A novel two-site chemodosimeter (SWJT-4) based on fluorescein skeleton to detect diethyl chlorophosphate (DCP) was designed and synthesized. It is a turn-on fluorescent probe for DCP with good selectivity and obvious color change in aqueous solution. Interestingly, the two oxime groups of SWJT-4 as dual response sites initiated different reactions with DCP to form a cyano group and an isoxazole ring, respectively. The corresponding mechanism was confirmed by 1H NMR, MS and DFT calculation. Moreover, SWJT-4 could be used as a fluorescent test paper to detect DCP vapor.

Urinary Concentrations of Dialkylphosphate Metabolites of Organophosphate pesticides in the Study of Asian Women and their Offspring's Development and Environmental Exposures (SAWASDEE)

BACKGROUND

Measurements of urinary dialkyl phosphate (DAP) metabolites are often used to characterize exposures to organophosphate (OP) insecticides; however, some challenges to using urinary DAP metabolites as an exposure measure exist. OP insecticides have short biological half-lives with measurement in a single urine sample typically only reflecting recent exposure within the last few days. Because of the field staff and participant burden of longitudinal sample collection and the high cost of multiple measurements, typically only one or two urine samples have been used to evaluate OP insecticide exposure during pregnancy, which is unlikely to capture an accurate picture of prenatal exposure.

METHODS

We recruited pregnant farmworker women in Chom Thong and Fang, two districts of Chiang Mai province in northern Thailand (N = 330) into the Study of Asian Women and their Offspring's Development and Environmental Exposures (SAWASDEE) from 2017 to 2019. We collected up to 6 serial urine samples per participant during gestation and composited the samples to represent early, mid, and late pregnancy. We measured concentrations of urinary DAP metabolites in the composited urine samples and evaluated the within- and between-participant variability of these levels. We also investigated predictors of OP insecticide exposure.

RESULTS

DAP metabolite concentrations in serial composite samples were weakly to moderately correlated. Spearman correlations indicated that composite urine samples were more highly correlated in Fang participants than in Chom Thong participants. The within-person variances (0.064-0.65) exceeded the between-person variances for DETP, DEP, ∑DEAP, DMP, DMTP, ∑DMAP, ∑DAP. The intraclass correlations (ICCs) for the volume-based individual metabolite levels (ng/mL) ranged from 0.10 to 0.66. For ∑DEAP, ∑DMAP, and ∑DAP the ICCs were, 0.47, 0.17, 0.45 respectively. We observed significant differences between participants from Fang compared to those from Chom Thong both in demographic and exposure characteristics. Spearman correlations of composite samples from Fang participants ranged from 0.55 to 0.66 for the ∑DEAP metabolite concentrations in Fang indicating moderate correlation between pregnancy periods. The ICCs were higher for samples from Fang participants, which drove the overall ICCs.

CONCLUSIONS

Collecting multiple (∼6) urine samples during pregnancy rather than just 1 or 2 improved our ability to accurately assess exposure during the prenatal period. By compositing the samples, we were able to still obtain trimester-specific information on exposure while keeping the analytic costs and laboratory burden low. This analysis also helped to inform how to best conduct future analyses within the SAWASDEE study. We observed two different exposure profiles in participants in which the concentrations and variability in data were highly linked to the residential location of the participants.

Neurological Sequela of Acute Pesticide Poisoning Among Adults in Central Taiwan

Background and Purpose: Cases of acute pesticide poisoning account for significant morbidity and mortality in developing countries; however, its burden in Taiwan remains unknown. The study examined acute pesticide poisoning (APP) involving adults in the central region of Taiwan, which is a mainly agricultural sub-urban area.

Methods: The retrospective study evaluated the outcome and neurological sequelae of patients with APP in a Taiwanese cohort between April 2002 and February 2019. The pesticides were classified according to the Insecticide Resistance Action Committee Mode of Action (MoA) classification. The clinical characteristics, duration of hospitalization (days), follow-up duration (years), in-hospital mortality, neurological sequela, and imaging findings were recorded. Furthermore, multivariate logistic regression analyses were performed.

Results: We identified 299 patients with APP comprising 206 (68.9%) adult men with a mean exposure age of 56.4 ± 16.8 years. Paraquat, organophosphates, pyrethroids, carmabates, and phosphinic acid were the most commonly known reported poisoning agents. The mortality rate was highest in users with paraquat (77.1%), followed by phosphinic acid (22.2%), carbamates (16.7%), and organophosphates (15.8%). After a mean follows up of 3.69 ± 2.26 years, the most common neurological sequela was a cognitive decline (56 among 225 survivors, 24.89%), peripheral neuropathy (11 among 225 survivors, 4.89%), tremor (10 among 225 survivors, 4.44%), ataxia (3/225, 1.33%), and parkinsonism feature (2/225, 0.89%). Brain imaging studies revealed basal ganglion lesions on CT or hyperintensity on T2-weighted MRI images in 26 among 46 patients (56.5%). The basal ganglion lesions on brain imaging had a positive correlation with neurological sequelae.

Conclusion: Acute pesticide poisoning (APP)-related mortality is high especially paraquat intoxication, and cognitive decline, as well as peripheral neuropathy, were the most common neurological sequelae among survivors, which is highly correlated with basal ganglia lesions on brain imaging.

Investigation of the Experimental Pharmacokinetics of the Bis-Chlorinated Bis-pyridinium Mono-aldoxime Cholinesterase Reactivator K-868 in Rats

Background:

The widespread use of organophosphorus compounds in agriculture and their existence in some military arsenals present continuous threats. Quaternary bis-pyridinium aldoximes are potent, highly polar cholinesterase reactivators and the most intensively studied candidate antidotes against poisoning with organophosphorus compounds.

Objective:

The in vivo experimental pharmacokinetic properties of K-868, a novel bis-chlorinated, bis-pyridinium mono-aldoxime are detailed and put in context with regard to similar compounds described earlier.

Methods:

Rats received 30 µmol K-868 i.m. and were sacrificed at various time points following treatment. Blood, cerebrospinal fluid and tear were collected, while the brains, eyes, kidneys, livers, lungs and testes were removed, dissected and homogenized. K-868 concentrations were determined using high performance liquid chromatography with ultraviolet absorption detection.

Results:

K-868 was detected in the eyes, kidneys, lungs and tear within 5 minutes in maximal serum concentrations attained 15 minutes following administration. Elimination was slow for K-868 which remained detectable at 120 minutes in the blood and the kidneys, and at 60 minutes in the eyes, lungs and tear following its administration. Nevertheless, its distribution was overall poor with areas under the 120-minute concentration curves (AUC120) showing close similarity in the blood and the kidneys, while reaching just approximately 5% of serum AUC120 in the eyes and lungs.

Conclusion:

K-868 is a potent candidate antidote against organophosphate poisoining with a prolonged presence in the circulation.

Changes of attention-related brain activity over 6 months after acute organophosphate pesticide poisoning: a prospective follow-up study

CONTEXT

Ingestion of organophosphate (OP) pesticides is a common method of self-harm in developing countries. Apart from acute cholinergic effects, limited evidence implicates OP poisoning in long-term neurocognitive deficits. However, prospective neurophysiological evidence of long-term deficits is scarce in humans. We aimed to determine long-term cognitive changes of acute OP pesticide self-poisoning in a prospective follow-up study, using event-related potentials (ERPs), an electroencephalographic index of cognitive functioning.

METHODS

We recruited 203 patients (147 men) hospitalised with OP pesticide ingestion (OP group; all had significant erythrocyte cholinesterase inhibition) and 50 patients (23 men) with paracetamol overdose (control group) as a means of self-harm. We recorded their ERPs and behavioural performance in a selective attention task at three post-exposure time points: on discharge from hospital (around 14 days post-ingestion), 6 weeks and 6 months post-ingestion. We compared the reaction time and ERP components of the two groups at each time point, adjusting for sex, age, education and comorbid depression in multiple regression models.

RESULTS

OP group had significantly slower reaction times than the control group on discharge and at 6 weeks, but not at 6 months. On discharge, the OP group also showed significantly prolonged latency of the parietal P3b component, signifying delayed attentional processing. P3b amplitudes were also significantly smaller in the OP group on discharge and at 6 months. Within the OP group, greater clinical severity of poisoning was associated with smaller P3b amplitudes. Early pre-attentive cortical processing (as indexed by N1 ERP component) showed no significant intergroup differences.

CONCLUSIONS

Acute OP pesticide poisoning was associated with impaired behavioural and neurophysiological indices of selective attention. These deficits outlast the cholinergic phase of intoxication. The neurobehavioral impairment disappears over months, but neurophysiological deficits seem to last even after 6 months. This impairment could potentially compromise the performance and safety of patients for months following clinical recovery.

Personalized nutrition for dementia prevention

The role of nutrition has been investigated for decades under the assumption of one-size-fits-all. Yet there is heterogeneity in metabolic and neurobiological responses to diet. Thus a more personalized approach may better fit biological reality and have increased efficacy to prevent dementia. Personalized nutrition builds on the food exposome, defined as the history of diet-related exposures over the lifetime, and on its interactions with the genome and other biological characteristics (eg, metabolism, the microbiome) to shape health. We review current advances of personalized nutrition in dementia research. We discuss key questions, success milestones, and future roadmap from observational epidemiology to clinical studies through basic science. A personalized nutrition approach based on the best prescription for the most appropriate target population in the most relevant time-window has the potential to strengthen dementia-prevention efforts.

Analysis of Multi-Pesticide Residues and Dietary Risk Assessment in Fresh Tomatoes (Lycopersicum esculentum) from Local Supermarkets of the Metropolitan Region, Chile

In recent years, the official authorities in Chile have reported transgressions in the maximum residue levels of pesticides in fresh vegetables. There is no official information about traceability, pesticide levels, and potential health risks. The aim of this study was to analyse pesticide residues and their corresponding dietary risk assessments in tomatoes from supermarkets in the Metropolitan Region. Pesticides were extracted using the Quick, Easy, Cheap, Effective, Rugged and Safe, QuEChERS method, and their concentrations were determined by using chromatography with HPLC-FL/UV and GC-MS/ECD/NPD, following the Analytical Quality Control and Method Validation Procedures for Pesticides Residues Analysis in Food and Feed, SANTE guide and ISO 17025:2017 standard. In addition, a dietary risk assessment was carried out by comparing Chilean data to international references. The results reported that 9% of the samples had pesticide residue levels above the maximum residue levels permitted in Chile. All the scenarios evaluated revealed the highest estimated daily intake and hazard quotients for methamidophos and chlorpyrifos. Both the active substances used were acetylcholinesterase inhibitors and were neurotoxic under chronic risk assessment. The results showed the highest chronic hazard index in the Chilean scenario for all age groups and genders. The evidence obtained revealed that methamidophos, methomyl, and chlorpyrifos should be restricted for their use in Chilean agriculture.

Bbc3 Loss Enhances Survival and Protein Clearance in Neurons Exposed to the Organophosphate Pesticide Chlorpyrifos

Exposure to environmental toxicants can increase the risk of developing age-related neurodegenerative disorders. Exposure to the widely used organophosphate pesticide chlorpyrifos (CPF) is associated with increased risk of developing Alzheimer's disease and Parkinson's disease, but the cellular mechanisms underlying CPF toxicity in neurons are not completely understood. We evaluated CPF toxicity in mouse primary cortical neuronal cultures, using RNA-sequencing to identify cellular pathways modulated by CPF. CPF exposure altered the expression of genes associated with intrinsic apoptosis, significantly elevating expression of the pro-apoptotic mediator Bbc3/Puma. Bbc3 loss attenuated CPF driven neurotoxicity, induction of other intrinsic apoptosis regulatory genes including Trp53 and Pmaip1 (encoding the NOXA protein), and cleavage of apoptosis executors caspase 3 and poly (ADP-ribose) polymerase (PARP). CPF exposure was associated with enhanced expression of endoplasmic reticulum stress-related genes and proteins and the accumulation of high molecular weight protein species in primary neuronal cultures. No evidence of alterations in the ubiquitin-proteosome system were observed, however, autophagy-related proteins were upregulated in CPF-treated Bbc3-/- neuronal cultures compared with identically exposed WT cultures. Elevated autophagy-related protein expression in Bbc3-/- neuronal cultures was associated with a reduction in CPF-induced high molecular weight alpha-synuclein and tau immunoreactive protein aggregates. Studies indicate that Bbc3-/- neuronal cultures enhance the endoplasmic reticulum stress response and upregulate protein clearance mechanisms as a component of resistance to CPF-mediated toxicity.

Long-Term Neurological and Psychological Distress Symptoms among Smallholder Farmers in Costa Rica with a History of Acute Pesticide Poisoning

Studies suggest that acute pesticide poisonings (APP) may be linked with long-term neurological effects. To examine long-term neurological and psychological distress symptoms associated with having experienced an APP, we conducted a cross-sectional study of 300 conventional and organic smallholder farmers from Zarcero County, Costa Rica, May–August 2016. We collected self-reported data on sociodemographic characteristics, occupational history, pesticide exposure, APPs, neurological and psychological distress symptoms (using the Brief Symptom Inventory (BSI)). Adjusted logistic regression models were fit. A total of 14% of the farmers (98% male) reported experiencing at least one APP during their lifetime. Self-reported APP was associated with neurological symptoms during the 12 months prior to interview (e.g., fainting (Odds Ratio: 7.48, 95% Confidence Interval: 1.83, 30.74), shaking hands (3.50; 1.60, 7.60), numbness/tingling in hands or feet (3.23; 1.66, 6.32), insomnia (2.53; 1.34, 4.79), accelerated heartrate (2.42; 1.03, 5.47), dizziness (2.38; 1.19, 4.72), increased irritability/anger (2.37; 1.23, 4.55), low energy (2.33; 1.23, 4.46), and difficulty concentrating (2.01; 1.05, 3.85)). Farmers who reported an APP in the ten years prior to interview experienced increased odds of abnormal BSI scores for hostility (4.51; 1.16, 17.70) and paranoid ideation (3.76; 0.99, 18.18). Having experienced an APP may be associated with long-term neurological and psychological distress symptoms.

Neurobehavioral, Neuromotor, and Neurocognitive Effects in Agricultural Workers and Their Children Exposed to Pyrethroid Pesticides: A Review

In recent years, pyrethroids have emerged as a less toxic alternative to eliminate insect pests. However, some animal studies and studies with children show that these pesticides are toxic and lead to neurobehavioral effects similar to other pesticides, such as organophosphates. The purpose of this review was to systematize the epidemiological scientific evidence about the neurobehavioral, neuromotor, and neurocognitive effects in agricultural workers and their children exposed to pyrethroid pesticides. We conducted two searches (with different terms) in PubMed and Scopus databases, including articles in Spanish and English language on the effects of occupational exposure to pyrethroid pesticides associated with neurobehavioral, neuromotor, and neurocognitive functioning of agricultural workers and their children. There were no filters by year, and the search included studies till march 2021. To develop the search, we followed the recommendations contained in the PRISMA guidelines and the PICO strategy. The results show that in 66.6% of the studies reviewed (8 of 12 studies), agricultural workers or their children occupationally exposed to pyrethroid pesticides have a higher risk of presenting difficulties in their neurocognitive, neuromotor, or neurobehavioral performance, mainly associated with attention, processing speed (linked to hand-eye coordination), and motor coordination. There are still few studies that address this issue. However, the quality of most of the research conducted (83% intermediate or high quality) confirms the risk for neurobehavioral health in agricultural workers due to occupational exposure to pyrethroids. More research is required evaluating the exposure to pyrethroids, including biomarkers and validated neurobehavioral and neuromotor tests, in addition to evaluating the effect of simultaneous exposure to other hazardous pesticides. Assuming that the use of pyrethroids is increasing considerably and faster than the scientific evidence, it is suggested as a precautionary principle to regulate, more strictly, the sale of pyrethroids and other pesticides.

Amorphous Selenium Nanoparticles Improve Vascular Function in Rats With Chronic Isocarbophos Poisoning via Inhibiting the Apoptosis of Vascular Endothelial Cells

Aim

This study aimed to investigate the preventive effect and possible mechanism of amorphous selenium nanoparticles (A-SeQDs) on isocarbophos induced vascular dysfunction.

Methods

A-SeQDs was made by auto redox decomposition of selenosulfate precursor. Male rats were given isocarbophos (0.5 mg/kg/2 days) by intragastric administration for 16 weeks to induce vascular dysfunction. During the course, A-SeQDs (50 mg/kg/day) was added to the water from week 5. Then, the rats were killed to observe and test the influence of A-SeQDs on the vascular dysfunction induced by isocarbophos. Finally, human umbilical vein endothelial cells (HUVECs) were treated with 10% DMEM of isocarbophos (100 μM) for 5 days to detect the related indexes. Before the use of isocarbophos treatment, different drugs were given.

Results

A-SeQDs could reduce total carbon dioxide, MDA, VCAM-1, ICAM-1, IL-1, and IL-6 while increasing oxygen saturation, NO content, and SOD activity in rats. A-SeQDs also resulted in relatively normal vascular morphology, and the expression of sodium hydrogen exchanger 1 (NHE1) and caspase-3 decreased in rats. Furthermore, in HUVECs treated with isocarbophos, A-SeQDs maintained mitochondrial membrane potential, inhibited the cleaved caspase-3 expression, and released cytochrome c from mitochondria to cytosol.

Conclusion

A-SeQDs can inhibit the apoptosis of HUVECs through the mitochondrial pathway, and effectively treat the impairment of vascular endothelial function caused by isocarbophos, which is NHE1-dependent.

Evaluation of occupational pesticide exposure on Egyptian male adolescent cognitive and motor functioning

BACKGROUND

Chronic low-level exposure to organophosphorus pesticides is associated with adverse health effects, including a decline in neurological functioning and long-term impairment. These negative effects may be more detrimental in children and adolescents due to their critical stage in development. Little work has investigated the effects of chronic exposure to pesticides, specifically chlorpyrifos (CPF) during the adolescent period.

OBJECTIVES

To examine effects of CPF exposure over a year-long period within a group of male adolescents in Egypt (N = 242, mean age = 17.36), including both pesticide applicators and non-applicators.

METHODS

Associations between average CPF exposure (measured via urinary metabolite levels of 3,5,6-trichloro-2-pyridinol [TCPy]) and neurobehavioral functioning were examined in a 1-year longitudinal study. Given previous literature, higher levels of TCPy were expected to be associated with worse neurobehavioral functioning.

RESULTS

Using mixed effects linear regression, average TCPy exposure predicted deficits in more complex neurobehavioral tasks (Benton visual retention, digit span reverse, match to sample, serial digit learning, and alternating tapping) with estimates of effects ranging from -0.049 to 0.031. Age (effects ranging from 0.033 to 0.090) and field station (effects ranging from -1.266 to -0.278) were significantly predictive of neurobehavioral functioning over time. An interaction effect was found for field station and TCPy across several neurobehavioral domains.

DISCUSSION

Results show that occupational exposure to pesticides may have particularly deleterious effects on complex neurobehavioral domains. Additionally, differences across field stations and the age at which individuals are exposed may be important factors to investigate in future research.

Agrochemical pesticide production, trade, and hazard: Narrowing the information gap in Colombia

Pesticides are a major tool for the intensification of agriculture, and helped to increase food, feed and biofuel production. Yet, there are persistent concerns about the negative effects of pesticides in human health and the environment, particularly in low and middle income countries (LMICs). Given the lack of information on pesticide exposure and hazard, Colombia exemplifies the need to narrow the information gap on pesticide risk in LMICs. We assessed pesticide hazard in Colombia based on the official toxicity categorization, compared it to more integral international standards, and identified main actions to narrow this information gap. Results showed that Colombia has been a relevant regional actor in pesticide production and trade, reaching almost 75 million kilogrammes and liters sold in 2016. Based on acute toxicity for humans, a quarter of the amount of pesticides sales and imports, and a third of the exports in 2016 ranged from moderately to extremenly toxic. The top-selling agrochemicals in 2016 (glyphosate with 14% of the total sales, chlorpyrifos 7.5% and mancozeb 6.9%) are also commonly used in other countries, reflecting a homogenized global industry. Compared to integral international categorizations, we found that for that year 63% of the pesticides sold with slightly acute toxicity are actually considered highly hazardous pesticides (HHP) for humans or the environment, evidencing the need to use a more integral hazard categorization in the country. Narrowing the information gap in pesticide use and associated risks demands a transparent process of knowledge creation and sharing, including funtional information and monitoring systems. This should be part of an integral assessment and regulation that better defines HHP, their production and trade to reduce pesticide risk while informing a transition towards sustainable food systems.

Organophosphorus poisoning in animals and enzymatic antidotes

Organophosphorus compounds (OPs) are neurotoxic molecules developed as pesticides and chemical warfare nerve agents (CWNAs). Most of them are covalent inhibitors of acetylcholinesterase (AChE), a key enzyme in nervous systems, and are therefore responsible for numerous poisonings around the world. Many animal models have been studied over the years in order to decipher the toxicity of OPs and to provide insights for therapeutic and decontamination purposes. Environmental impact on wild animal species has been analyzed to understand the consequences of OP uses in agriculture. In complement, various laboratory models, from invertebrates to aquatic organisms, rodents and primates, have been chosen to study chronic and acute toxicity as well as neurobehavioral impact, immune response, developmental disruption, and other pathological signs. Several decontamination approaches were developed to counteract the poisoning effects of OPs. Among these, enzyme-based strategies are particularly attractive as they allow efficient external decontamination without toxicity or environmental impact and may be of interest for treatment. Approaches using bioscavengers for prophylaxis, treatment, and external decontamination are emphasized and their potential is discussed in the light of toxicological observations from various animal models. The relevance of animal models, regarding their cholinergic system and the abundance of naturally protecting enzymes, is also discussed for better extrapolation of results to human.

Environmental Health Threats to Latino Migrant Farmworkers

Approximately 75% of farmworkers in the United States are Latino migrants, and about 50% of hired farmworkers do not have authorization to work in the United States. Farmworkers face numerous chemical, physical, and biological threats to their health. The adverse effects of these hazards may be amplified among Latino migrant farmworkers, who are concurrently exposed to various psychosocial stressors. Factors such as documentation status, potential lack of authorization to work in the United States, and language and cultural barriers may also prevent Latino migrants from accessing federal aid, legal assistance, and health programs. These environmental, occupational, and social hazards may further exacerbate existing health disparities among US Latinos. This population is also likely to be disproportionately impacted by emerging threats, including climate change and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Latino migrant farmworkers are essential to agriculture in the United States, and actions are needed to protect this vulnerable population.

Chronic Exposure to Organophosphates Pesticides and Risk of Metabolic Disorder in Cohort from Pakistan and Cameroon

(1) Background: Organophosphorus pesticides (OPPs) are major chemicals used in agriculture for eradication of insecticides/pesticides. Unfortunately, the longtime exposure of human beings to OPPs could lead to metabolic disorder such as high blood pressure, hyperglycemia, overweight or dyslipidemia. The aim of this research is to evaluate the possible metabolic dysregulations as a consequence of chronic OPPs exposure to individuals in Cameroon and Pakistan. (2) Methods: Blood samples were collected from 300 participants in each country, into ethylenediaminetetraacetic acid (EDTA) tubes. The samples were extracted with solid phase extraction (methanol/water) for analysis of OPPs with gas chromatography mass spectrometry. The spectrophotometry and Enzyme Linked ImmunoSorbent Assay (ELISA) were used to measure the hepatic, renal, pancreatic and cardiovascular functions. The atherogenic index (AI) was also determined in OPPs exposed and nonexposed cohorts. (3) Results: The results showed the presence of malathion, parathion and chlorpyrifos OPPs residues in Cameroonians, and malathion and chlorpyrifos in Pakistani samples, respectively. Elevated Body Mass Index (BMI), insulin, blood glucose, dyslipidemia and hypertension were noted in OPPs chronic exposed groups. In addition, dysregulated liver and kidney function profiles were observed in all participants regardless of gender and age groups. (4) Conclusions: The study concludes that both the study cohorts showed several metabolic dysregulations attributable to chronic exposure to a mixture of OPPs which may provide precursors for establishment of metabolic syndrome and other chronic diseases. Further different extended population-based studies are suggested to understand the differential metabolic dysfunctions caused by structurally different OPPs mixtures exposure.

Health problems in agricultural workers occupationally exposed to pesticides

Agricultural workers are susceptible to several health problems as a result of occupational exposure to toxic substances, especially pesticides. The aim of this review was to describe the health issues associated with occupational exposure to pesticides in agricultural workers. A descriptive study, in the form of an integrative literature review, was conducted based on articles retrieved from the LILACS, SciELO and PubMed databases, published between January 2015 and October 2018. The searches were conducted using the keywords "pesticides," "workers' health," "occupational exposure" and "agricultural workers." The study was guided by the following research question: what health problems do agricultural workers experience as a result of occupational exposure to pesticides? The screening process led to the selection of 35 studies performed in several countries and continents, all of which shed light on the vulnerability of agricultural workers, especially due to the misuse of personal protective equipment and lack of knowledge about the correct use of these devices. The studies investigated a variety of health issues, and most reported a positive association between these conditions, which include cancer, and the use of pesticides. Educational and preventive measures must be implemented to promote the health of rural workers. Furthermore, it is crucial that governments play an active role in these initiatives and provide alternatives to pesticides for pest control.