Anxiety and depression following cumulative low-level exposure to organophosphate pesticides

Depressive symptoms and suicide attempts among farmers exposed to pesticides

Pesticides safeguard crop health but may diminish cholinesterase activity in farmers, potentially leading to psychiatric disorders like depression and suicide attempts. This study, with 453 participants (225 pesticide-exposed farmers, 228 non-farmers) in Almería, Spain, aimed to investigate the presence of depressive symptoms and suicide attempts, the decrease acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity, and their relationship with pesticide exposure in farmers. Depressive symptoms were evaluated using the Spanish adaptation of the Beck Depression Inventory, and blood samples were analyzed for AChE and BChE activity. Farmers showed significantly increased risk of moderate/severe depression and suicide attempts compared to non-farmers (OR = 2.18; p = 0.001), with highest risks observed among mancozeb users (OR = 2.76; p = 0.001 for depression) and malathion users (OR = 3.50; p = 0.001 for suicide attempts). Findings emphasize elevated depression and suicide risks among pesticide-exposed farmers, particularly associated with chlorpyrifos, mancozeb, and malathion exposure.

Organophosphorus pesticide exposure from house dust and parent-reported child behavior in Latino children from an orchard community

BACKGROUND

Organophosphorus pesticide (OP) exposure is known to have adverse effects on the nervous system. Children from agricultural communities are at risk of exposure to these chemicals from their indoor environments that can lead to neurological and developmental problems, including changes in behavior.

OBJECTIVE

The aim of this study is to evaluate whether the take-home pathway exposure is associated with behavioral and emotional problems in Latino Orchid Community children.

METHOD

The study was implemented over a period of two years (2008-2010) in an orchard farming community with a total of 324 parents who had children between the ages of 5-12 years old. Mothers of the children were asked to complete the Child Behavior Checklist (CBCL) and dust from their carpets was collected. Emotional and behavioral deficits were assessed based on the CBCL and house dust was assessed for OP concentrations. In this study, correlations between OPs in house dust and CBCL subscales were estimated using linear regression models with total OP concentrations classified by tertiles. This study also facilitated the comparison between the agricultural and non-agricultural families in terms of behavioral deficits and house dust concentrations of pesticides.

RESULTS

The data from the study shows that there was a positive association between the concentration of OP residues in house dust and internalizing behavior (β=2.06, p=0.05) whereas the association with externalizing behavior was not significant after accounting for sociocultural covariates. Significant positive associations of OP residues with somatic problems (p=0.02) and thought problems (p=0.05) were also found.

CONCLUSION

The data support a potential role of OP exposure in childhood development, with a specific focus on internalizing behavior. Future work focused on longitudinal studies may uncover the long-term consequences of OP exposure and behavior.

Ambient long-term exposure to organophosphorus pesticides and the human gut microbiome: an observational study

BACKGROUND

Organophosphorus pesticides (OP) have been associated with various human health conditions. Animal experiments and in-vitro models suggested that OP may also affect the gut microbiota. We examined associations between ambient chronic exposure to OP and gut microbial changes in humans.

METHODS

We recruited 190 participants from a community-based epidemiologic study of Parkinson's disease living in a region known for heavy agricultural pesticide use in California. Of these, 61% of participants had Parkinson's disease and their mean age was 72 years. Microbiome and predicted metagenome data were generated by 16S rRNA gene sequencing of fecal samples. Ambient long-term OP exposures were assessed using pesticide application records combined with residential addresses in a geographic information system. We examined gut microbiome differences due to OP exposures, specifically differences in microbial diversity based on the Shannon index and Bray-Curtis dissimilarities, and differential taxa abundance and predicted Metacyc pathway expression relying on regression models and adjusting for potential confounders.

RESULTS

OP exposure was not associated with alpha or beta diversity of the gut microbiome. However, the predicted metagenome was sparser and less evenly expressed among those highly exposed to OP (p = 0.04). Additionally, we found that the abundance of two bacterial families, 22 genera, and the predicted expression of 34 Metacyc pathways were associated with long-term OP exposure. These pathways included perturbed processes related to cellular respiration, increased biosynthesis and degradation of compounds related to bacterial wall structure, increased biosynthesis of RNA/DNA precursors, and decreased synthesis of Vitamin B1 and B6.

CONCLUSION

In support of previous animal studies and in-vitro findings, our results suggest that ambient chronic OP pesticide exposure alters gut microbiome composition and its predicted metabolism in humans.

Sex-specific neurobehavioral and biochemical effects of developmental exposure to Malathion in offspring mice

Malathion is an organophosphate pesticide (OP) commonly used in agriculture, industry, and veterinary medicine. Sex is a crucial factor in responding to neurotoxicants, yet the sex-specific effects of OP exposure, particularly neurological impairments following chronic low-level exposure remains limited. Our study aims to evaluate the neurobehavioral and biochemical effects of developmental exposure to Malathion across sexes. Pregnant mice were exposed to a low oral dose of Malathion from gestation up to the weaning of the pups, which were individually gavaged with a similar dose regimen until postnatal day 70. Our results show that Malathion decreased body weight and food intake, reduced locomotor activity and recognition memory. Motor coordination and special memory were only altered in females, whereas we found a male-specific effect of Malathion on social behavior and marble burying. These alterations were accompanied by increased malondialdehyde (MDA), decreased brain acetylcholinesterase activity (AChE), and disrupted brain redox homeostasis. Our findings about the effects of Malathion exposure across sexes may, in part, contribute to understanding the dimorphic susceptibilities observed in neurological disorders.

Mental Health Disorders among Thai Farmers: Occupational and Non-Occupational Stressors

This cross-sectional study aimed to identify occupational and non-occupational factors that impact levels of stress, depression, and anxiety among farmers located in the northern part of Thailand, including the potential psychological impacts of pesticide use. The participants (N=270) were interviewed with a survey adopted and modified from peer-reviewed articles and questionnaires. The survey consists of four parts, including demographic information and pesticide exposure; perceived farm stressors employing Farm Stressor Survey (FSS); mental health disorder utilizing Srithanya Stress Scale (ST5), Nine-Questions Depression- Rating Scale (9Q), and Depression Anxiety Stress Scale 21 (DASS21); in addition to COVID-related stress utilizing COVID Stress Scale (CSS). The participants were categorized into two groups i.e., Spray and No Spray based on their self-reported occupational use of pesticide spraying within the past year. No significant associations were observed between occupational pesticide exposures and mental health disorder scores. Being female, having a second job besides a farmer, having applied pesticides for greater than 20 years, and having a higher farm stressor perception showed a significant positive association with self-reported mental health disorders; while having a good agricultural practice and PPE use showed a significant negative association with those outcomes. This pilot study scrutinized expanded sources of stress in farm work and provided information for the development of more effective mental disorder intervention programs for Thai farmers.

Glyphosate: Impact on the microbiota-gut-brain axis and the immune-nervous system, and clinical cases of multiorgan toxicity

Glyphosate (GLP) and GLP-based herbicides (GBHs), such as polyethoxylated tallow amine-based GLP surfactants (GLP-SH), developed in the late 70', have become the most popular and controversial agrochemicals ever produced. Nowadays, GBHs have reached 350 million hectares of crops in over 140 countries, with an annual turnover of 5 billion and 11 billion USD in the U.S.A. and worldwide, respectively. Because of the highly efficient inhibitory activity of GLP targeted to the 5-enolpyruvylshikimate-3-phosphate synthase pathway, present in plants and several bacterial strains, the GLP-resistant crop-based genetic agricultural revolution has decreased famine and improved the costs and quality of living in developing countries. However, this progress has come at the cost of the 50-year GBH overuse, leading to environmental pollution, animal intoxication, bacterial resistance, and sustained occupational exposure of the herbicide farm and companies' workers. According to preclinical and clinical studies covered in the present review, poisoning with GLP, GLP-SH, and GBHs devastatingly affects gut microbiota and the microbiota-gut-brain (MGB) axis, leading to dysbiosis and gastrointestinal (GI) ailments, as well as immunosuppression and inappropriate immunostimulation, cholinergic neurotransmission dysregulation, neuroendocrinal system disarray, and neurodevelopmental and neurobehavioral alterations. Herein, we mainly focus on the contribution of gut microbiota (GM) to neurological impairments, e.g., stroke and neurodegenerative and neuropsychiatric disorders. The current review provides a comprehensive introduction to GLP's microbiological and neurochemical activities, including deviation of the intestinal Firmicutes-to-Bacteroidetes ratio, acetylcholinesterase inhibition, excitotoxicity, and mind-altering processes. Besides, it summarizes and critically discusses recent preclinical studies and clinical case reports concerning the harmful impacts of GBHs on the GI tract, MGB axis, and nervous system. Finally, an insightful comparison of toxic effects caused by GLP, GBH-SH, and GBHs is presented. To this end, we propose a first-to-date survey of clinical case reports on intoxications with these herbicides.

Pesticide Exposure or Pesticide Poisoning and the Risk of Depression in Agricultural Populations: A Systematic Review and Meta-Analysis

Evidence suggests that farm workers represent a high-risk population for the development of depression. The aim of the study was to clarify the association between pesticide exposure/poisoning and depression. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis were conducted in this systematic review and meta-analysis. Relevant studies were included through searching in PubMed, Scopus, Web of Science, ProQuest, CINAHL and pre-print services databases. A total of eight studies were included. A positive but non-significant association was observed between pesticide use and depression (OR = 1.123; 95% CI, 0.932-1.354, p-value = .221) while a significant positive association was observed between pesticide poisoning and depression (OR = 2.942; 95% CI, 1.791-4.831, p-value < .001). The present meta-analysis suggested clearly a significant positive association between pesticide poisoning and depression, confirming the hypothesis that pesticide poisoning is a risk factor of depression. It also revealed positive, yet non-significant association, between pesticide exposure and depression, a finding that enhances recent research but requires to be further supported by future cohort studies, including socioeconomic factors and biomarkers of depression.

Redox imbalance and inflammation: A link to depression risk in brazilian pesticide-exposed farmers

This study aims to elucidate the mechanisms linking occupational pesticide exposure to depression among rural workers from Maravilha, Brazil. We assessed the mental health, oxidative, and inflammatory profiles of farmers exposed to pesticides (N = 28) and compared them to an urban control group without occupational exposure to pesticides (N = 25). Data on sociodemographic, occupational history, and clinical records were collected. Emotional states were evaluated using the State-Trait Anxiety Inventory (STAI) and Beck Depression Inventory (BDI). Biochemical, hematological, inflammatory, and redox parameters were examined in blood samples from both groups. Results showed educational disparities between groups and unveiled a concerning underutilization of personal protective equipment (PPEs) among farmers. Glyphosate was the predominant pesticide used by farmers. Farmers exhibited higher BDI scores, including more severe cases of depression. Additionally, elevated levels of creatinine, ALT, AST, and LDH were observed in farmers, suggesting potential renal and hepatic issues due to pesticide exposure. Oxidative stress markers, such as increased lipid peroxidation and superoxide dismutase (SOD) activity, along with decreased catalase (CAT) activity and ascorbic acid levels, were noted in the pesticide-exposed group compared to controls. Elevated levels of inflammatory cytokines, particularly IL-1β, IL-6 and TNF-α, were also observed in pesticide-exposed group. Our findings suggest that inflammation, oxidative distress and lower educational levels may be associated with depression in pesticide-exposed farmers. This study highlights the impact of occupational pesticide exposure on the mental health of rural workers. The underuse of PPEs and the link between depressive symptoms, inflammation, and oxidative stress underscore the urgent need for improved safety measures in agricultural practices. Addressing these issues will contribute to a deeper understanding of the intricate relationship between environmental exposures and mental health outcomes.

Indicators of occupational pesticide exposure are associated with psychiatric symptoms

In southeastern Spain, intensive and highly productive agriculture under plastic also poses a risk to human health, as evidenced by reports on acute pesticide poisoning and its effects on mental health. However, knowledge of chronic exposures and their relationship to psychiatric disorders is still limited. This study analyzed the relationship between occupational exposure to pesticides and psychiatric disorders in farmers from Almería. A cross-sectional study was conducted amongst a coastal population in Almería, where over 32,800 ha of land are dedicated to intensive agriculture in plastic greenhouses. A total of 409 people participated in the study: 203 farmers and 206 control subjects. The highest risk of psychiatric disorders was observed in farmers living in areas of high exposure to pesticides, working in greenhouses (intensive agriculture), without protective goggles and without wearing masks. This study supports previous evidence of an elevated risk of psychiatric disorders among farm workers exposed to pesticides.

Organophosphate ester flame retardants and plasticizers in house dust and mental health outcomes among Canadian mothers: A nested prospective cohort study in CHILD

Organophosphate ester flame retardants and plasticizers (OPEs) are common exposures in modern built environments. Toxicological models report that some OPEs reduce dopamine and serotonin in the brain. Deficiencies in these neurotransmitters are associated with anxiety and depression. We hypothesized that exposure to higher concentrations of OPEs in house dust would be associated with a greater risk of depression and stress in mothers across the prenatal and postpartum periods. We conducted a nested prospective cohort study using data collected on mothers (n = 718) in the CHILD Cohort Study, a longitudinal multi-city Canadian birth cohort (2008-2012). OPEs were measured in house dust sampled at 3-4 months postpartum. Maternal depression and stress were measured at 18 and 36 weeks gestation and 6 months and 1 year postpartum using the Centre for Epidemiologic Studies for Depression Scale (CES-D) and Perceived Stress Scale (PSS). We used linear mixed models to examine the association between a summed Z-Score OPE index and continuous depression and stress scores. In adjusted models, one standard deviation increase in the OPE Z-score index was associated with a 0.07-point (95% CI: 0.01, 0.13) increase in PSS score. OPEs were not associated with log-transformed CES-D (β: 0.63%, 95% CI: -0.18%, 1.46%). The effect of OPEs on PSS score was strongest at 36 weeks gestation and weakest at 1 year postpartum. We observed small increases in maternal perceived stress levels, but not depression, with increasing OPEs measured in house dust during the prenatal and early postpartum period in this cohort of Canadian women. Given the prevalence of prenatal and postpartum anxiety and the ubiquity of OPE exposures, additional research is warranted to understand if these chemicals affect maternal mental health.

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.

Could pesticide exposure be implicated in the high incidence rates of depression, anxiety and suicide in farmers? A systematic review

Pesticide exposure and poisoning may rise the risk of mental health problems and suicidal tendencies. To explore the potential connection between chronic occupational exposure to pesticides and depression, anxiety, and suicide-related outcomes in farmers, a systematic review was performed. Systematic review protocol is available in PROSPERO registration number CRD42022316285. A total of fifty-seven studies met inclusion criteria: twenty-nine on depression or other mental disorders, twelve on suicide (two of them on both depression and suicide), and fourteen on pesticide poisoning or self-poisoning and death. Among the fifty-seven selected studies, eighteen were conducted in Asia, seventeen in North America, fourteen in South America, seven in European Union, one in Africa, and one in Australia/Oceania. Selected studies demonstrated an increased prevalence of depressive disorders in farmworkers exposed to pesticides as well as an increased self-reported prevalence of depression in this population. Moreover, previous pesticide poisoning increased the risk estimates for depression or other mental disorders as compared with chronic pesticide exposure. Severe pesticide poisoning and multiple poisoning showed increased risks of depressive symptoms compared with milder cases. In addition, financial difficulties and poor health were positively correlated with depression. Among studies on suicide, nine of them found that suicide rates increased in areas devoted to agriculture with intensive pesticide consumption. Moreover, studies demonstrate a higher suicide risk among farmers. The present review suggests more attention to the farmer's mental health and more detailed studies on occupational exposure to the mixture of these compounds.

Neurobehavioral Responses and Toxic Brain Reactions of Juvenile Rats Exposed to Iprodione and Chlorpyrifos, Alone and in a Mixture

Herein, male juvenile rats (23th postnatal days (PND)) were exposed to chlorpyrifos (CPS) (7.5 mg/kg b.wt) and/or iprodione (IPD) (200 mg IPD /kg b.wt) until the onset of puberty (60th day PND). Our results demonstrated that IPD and/or CPS exposure considerably reduced locomotion and exploration. However, CPS single exposure induced anxiolytic effects. Yet, neither IPD nor IPD + CPS exposure significantly affected the anxiety index. Of note, IPD and/or CPS-exposed rats showed reduced swimming time. Moreover, IPD induced significant depression. Nonetheless, the CPS- and IPD + CPS-exposed rats showed reduced depression. The individual or concurrent IPD and CPS exposure significantly reduced TAC, NE, and AChE but increased MDA with the maximum alteration at the co-exposure. Moreover, many notable structural encephalopathic alterations were detected in IPD and/or CPS-exposed rat brain tissues. The IPD + CPS co-exposed rats revealed significantly more severe lesions with higher frequencies than the IPD or CPS-exposed ones. Conclusively, IPD exposure induced evident neurobehavioral alterations and toxic reactions in the brain tissues. IPD and CPS have different neurobehavioral effects, particularly regarding depression and anxiety. Hence, co-exposure to IPD and CPS resulted in fewer neurobehavioral aberrations relative to each exposure. Nevertheless, their simultaneous exposure resulted in more brain biochemistry and histological architecture disturbances.

Psychological Morbidity in the Farming Community: A Literature Review

The mental health of the farming community across industrialised nations has long been a major concern. Using an adapted procedure for a systematic literature review of observational epidemiological studies reporting prevalence (informed by the Joanna Briggs Institute method), this paper reviews peer-reviewed literature that explicitly compares farmer and non-farmer mental health (n = 48). In doing so, it provides a central and accessible evidence base for researchers and practitioners, and simultaneously reveals a stark lack of consensus; specifically, 54.0% of measures deployed to assess farmer mental health determined it to be the same as or even better than non-farming populations. This ambiguity sits in sharp contrast to the unequivocally worrisome farmer suicide statistics. Informed by the literature, the paper discusses potential reasons for this mismatch, including (i) farmers' progression through a different "pathway" to suicide that is not always preceded by mental illness, and (ii) a failure of current methods to accurately gauge the mental health status of farmers. The paper concludes by recommending more research into farmers' "pathway" to suicide, and highlights the need for a dedicated and multi-disciplinary programme of methods research that will afford a more culturally appropriate and effective means of understanding mental health in the farming community.

Chronic exposure to metam sodium-based pesticide in mice during adulthood elevated anxiety and depression-like behaviors: Involvement of serotoninergic depletion and gut microbiota dysbiosis

Metam sodium-based pesticide (MS-BP) is widely used in agriculture and public health. We have previously demonstrated that maternal exposure to MS-BP resulted in sensorimotor alterations in mice offspring with long-lasting deficits including anxiety- and depression-like behaviors. Here, we project to verify whether these two neurobehavioral effects occur during adulthood following direct exposure to MS-BP and whether it results in changes in the serotoninergic system and gut microbiota. Our findings showed that chronic exposure to MS-BP increased anxiety- and depression-like behaviors, accompanied by a depletion of serotonin-like neurons within the dorsal raphe nucleus and a reduction in serotoninergic terminals in the infralimbic cortex and the basolateral amygdala. In addition, all MS-BP-exposed animals exhibited a reduced total bacterial number and diversity of gut microbiota. Taken together, our data demonstrated that MS-BP-induced behavioral changes could be related to the impairment of the serotoninergic system and gut microbiota dysbiosis.

Neurobehavioral Effects of Low-Dose Chronic Exposure to Insecticides: A Review

The modes of action of insecticides frequently involve a neurotoxic effect; therefore, the study of neurotoxic effects caused by long-term and low-dose insecticide exposure is of particular interest. This study looks at whether or not new studies conducted after 2009 and up to 2021 have provided new evidence for a better understanding of the actual neurobehavioral risk associated with long-term insecticide exposure. We selected and reviewed studies carried out on the neurobehavioral effects of neurotoxic insecticides (organophosphates and/or carbamates, pyrethroids, multiple or undefined insecticides, and organochlorines) considering occupational and non-occupational exposures. The articles were also scored and ranked based on seven parameters. Eighty-six studies were chosen for a final review process from among the 950 scientific papers identified. Twenty-six addressed occupational exposure and six environmental exposure. Among the latter group of studies, 17 focused on rural residents, to be assumed exposed because of living in rural areas, and 43 on the general population. Pending doubts have not been resolved in the last ten years due to the presence of contradictory and hardly comparable results and the fact that in most of the studies showing an evident neurobehavioral impairment the frequent presence of a previous episode of poisoning and hospitalization, with severe brain hypoxia, impaired the possibility of confirming the presence of a causal association with insecticide exposure. Interestingly, the most severely exposed groups, such as applicators who did not wear personal protective equipment, performed worse on neurobehavioral tests. As for residential exposure, there is sufficient evidence to suggest that prenatal OP exposure may increase the risk of ADHD in children.

Neuroprotective effect of piracetam-loaded magnetic chitosan nanoparticles against thiacloprid-induced neurotoxicity in albino rats

Thiacloprid (TH) is a neurotoxic agricultural insecticide and potential food contaminant. The purpose of this study was to investigate the relationship between TH exposure and memory dysfunction in rats, as well as the potential protective effect of piracetam and piracetam-loaded magnetic chitosan nanoparticles (PMC NPs). Rats were divided into five equal groups (six rats/group). The control group received saline. Group II was treated with PMC NPs at a dose level of 200 mg/kg body weight (Bwt); Group III was treated with 1/10 LD₅₀ of TH (65 mg/kg Bwt); Group IV was treated with TH (65 mg/kg Bwt) and piracetam (200 mg/kg Bwt); Group V was co-treated with TH (65 mg/kg Bwt) and PMC NPs (200 mg/kg Bwt). All animal groups were dosed daily for 6 weeks by oral gavage. Footprint analysis, hanging wire test, open field test, and Y-maze test were employed to assess behavioral deficits. Animals were euthanized, and brain tissues were analyzed for oxidative stress biomarkers, proinflammatory cytokines, and gene expression levels of glial fibrillary acidic protein (GFAP), amyloid-beta precursor protein (APP), B-cell lymphoma 2 (Bcl-2), and caspase-3. Brain and sciatic nerve tissues were used for the evaluation of histopathological changes and immunohistochemical expression of tau protein and nuclear factor kappa B (NF-κB), respectively. The results revealed that TH-treated rats suffered from oxidative damage and inflammatory effect on the central and peripheral nerves. The administration of PMC NPs considerably protected against TH-induced neuronal damage, increased antioxidant enzyme activity, decreased inflammatory markers, and improved behavioral performance than the group treated with piracetam. The neuroprotective effect of PMC NPs was mediated through the inhibition of GFAP, APP, caspase-3, Tau, and NF-κB gene expression with induction of Bcl-2 expression. In conclusion, TH could induce oxidative stress, inflammatory and neurobehavior impairment in rats. However, PMC NPs administration markedly mitigated TH-induced brain toxicity, possibly via oxidative and inflammatory modulation rather than using piracetam alone.

Association Between COPD Symptoms and Psychological Distress Among Farmers

BACKGROUND

Farmers have an increased risk of developing chronic obstructive pulmonary disease (COPD) and psychological distress. The potential role of psychological distress in worsening COPD symptoms has been reported among the general population, but no studies have examined this relationship among farmers with COPD, which is the purpose of this study.

METHODS

This study used the data from the 2017 Behavioral Risk Factor Surveillance System (BRFSS). Farmers reporting both psychological distress and COPD symptoms were included in this study (n = 239). Both unadjusted and adjusted logistic regressions were used to explore the association among psychological distress, age, health status, smoking, and COPD symptoms, with crude and adjusted odds ratio (OR) and 95% CIs reported.

FINDINGS

The unadjusted analysis suggested that COPD symptoms were significantly associated with psychological distress among farmers (OR = 2.05 [1.18, 3.58]). While adjusted models showed the significant association between COPD symptoms and psychological distress among farmers after controlling for smoking, age, and health status (adjusted OR = 2.08 [1.10, 4.01]).

CONCLUSION/IMPLICATIONS FOR PRACTICE

These results suggest that psychological distress is associated with an increased risk of COPD symptoms in farmers, which is consistent with observations from studies in non-farmers. Occupational health professionals need to provide screen for COPD among farmers as well as psychological distress screening and mental health promotion among farmers with COPD.

Behavioral and neurochemical impairments after intranasal administration of chlorpyrifos formulation in mice

Among the most relevant environmental factors associated with the etiology of neurodegenerative disorders are pesticides. Spray drift or volatilization generates pesticide dispersion after its application. In addition, inhalation or intranasal (IN) administration of xenobiotics constitutes a feasible route for substance delivery to the brain. This study investigates the behavioral and neurochemical effects of IN exposure to a commercial formulation of chlorpyrifos (fCPF). Adult male CF-1 mice were intranasally administered with fCPF (3-10 mg/kg/day) three days a week, for 2 weeks. Behavioral and biochemical analyses were conducted 20 and 30 days after the last IN fCPF administration, respectively. No significant behavioral or biochemical effects were observed in the 3 mg/kg fCPF IN exposure group. However, animals exposed to 10 mg/kg fCPF showed anxiogenic behavior and recognition memory impairment, with no effects on locomotor activity. In addition, the IN administration of 10 mg/kg fCPF altered the redox balance, modified the activity of enzymes belonging to the cholinergic and glutamatergic pathways, and affected glucose metabolism, and cholesterol levels in different brain areas. Taken together, these observations suggest that these biochemical imbalances could be responsible for the neurobehavioral disturbances observed after IN administration of fCPF in mice.

Neurotoxicity of pesticides in the context of CNS chronic diseases

Following the introduction and application of pesticides in human life, they have always been along with health concerns both in acute poisoning and chronic toxicities. Neurotoxicity of pesticides in chronic exposures has been known as one of the most important human health problems, as most of these chemicals act through interacting with some elements of nervous system. Pesticide-induced neurotoxicity can be defined in different categories of neurological disorders including neurodegenerative (Alzheimer, Parkinson, amyotrophic lateral sclerosis, multiple sclerosis), neurodevelopmental (attention deficit hyperactivity disorder, autism spectrum disorders, developmental delay, and intellectual disability), neurobehavioral and neuropsychiatric (depression/suicide attempt, anxiety/insomnia, and cognitive impairment) disorders some of which are among the most debilitating human health problems. In this review, neurotoxicity of pesticides in the mentioned categories and sub-categories of neurological diseases have been systematically presented in relation to different route of exposures including general, occupational, environmental, prenatal, postnatal, and paternal.

Potential Effects on Mental Health Status Associated with Occupational Exposure to Pesticides among Thai Farmers

Pesticide-related mental health issues in Thailand, an upper-middle-income country, are not well known. This study aimed to investigate the association between the history of occupational exposure to pesticides and the mental health of Thai farmers. A cross-sectional study was carried out in the areas around Chiang Mai, a large city in Northern Thailand, between June 2020 and January 2021. A total of 6974 farmers from six districts were interviewed to determine whether they regularly experienced symptoms related to mental health by the Self-Reporting Questionnaire (SRQ-20) as well as their lifetime history of agricultural pesticide exposure from 31 active ingredients and five functional categories: insecticides, herbicides, fungicides, rodenticides, and molluscicides. The cut-off of 6 was used to evaluate probable mental disorder. Most of the farmers under investigation were men (53.8%), with a mean age of 55.2 (11.7) years, and were involved mainly in the planting of rice, fruit, and vegetables. About 86.7% reported having used pesticides on their crops at some point in their lives-mostly glyphosate, paraquat, 2,4-D, methomyl, and carbofuran. All functional groups, as well as pesticide classes like organochlorines, organophosphates, and carbamates, were significantly associated with a higher risk of probable mental disorder based on exposure duration, frequency, personal protective equipment usage, and hygienic behavior. In a model with multiple pesticides, there was an association between mental disorder and exposure to endosulfan (AOR = 2.27, 95%CI = 1.26-4.08) and methyl parathion (AOR = 2.26, 95%CI = 1.26-4.06). Having previously reported pesticide poisoning symptoms was related to mental disorder (AOR = 7.97, 95%CI = 5.16-12.31), the findings provided evidence of pesticide exposure posing a risk to farmers' mental health, particularly long-term and high-intensity exposure.

Health-related quality of life within agriculture in England and Wales: results from a EQ-5D-3L self-report questionnaire

BACKGROUND

Mental and physical health problems among the farming community are well documented but there is limited evidence regarding the overall health status of this population. This paper offers a unique insight into this issue through presenting the findings from a survey instrument, the EQ-5D-3L, which provides a standardised measure of health-related quality of life (HRQOL).

METHODS

We conducted the largest ever survey (n = 15,296) of people living and working in agriculture in England and Wales to gather baseline data on health and wellbeing within this community. The survey included an assessment of HRQOL through the use of the EQ-5D-3L self-report questionnaire. A variety of statistical approaches were used to test for significant associations between HRQOL and sub-group characteristics, including the Chi-square test for independence, the Kruskal-Wallis test, and Mann-Whitney U-test. Binary logistic regression models were also created to assess the influence of a set of respondent characteristics on the likelihood of respondents reporting health problems in the EQ-5D-3L.

RESULTS

24% of respondents reported problems with mobility; 4% reported problems with self-care; 21% reported problems with performing their usual activities; 52% reported problems with pain/discomfort; and 31% reported problems with anxiety/depression. The mean EQ-5D index value was 0.811 (median (Md) 0.796, interquartile range (IQR) 0.275). The mean self-rated health score (EQ-VAS) was 77.6 (SD 16.1) (Md 80.0, IQR 20). In general, holding other respondent characteristics equal, women reported fewer problems with mobility, self-care, performing usual activities and pain/discomfort than men, but more problems with anxiety/depression. HRQOL in the working-aged appears to be poorer among the survey population than the wider UK population.

CONCLUSIONS

Results reveal concerning levels of physical and mental health problems, especially pain/discomfort and anxiety/depression, which appear to be more prevalent within our sample than within the wider UK population. There were important gender and age-related differences in both mental and physical health. Combatting these problems through targeted support is essential for the wellbeing of the farming community and the future sustainability of UK food production.

Long-Term Anxiety-Like Behavior and Microbiota Changes Induced in Mice by Sublethal Doses of Acute Sarin Surrogate Exposure

Anxiety disorder is one of the most reported complications following organophosphorus (OP) nerve agent (NA) exposure. The goal of this study was to characterize the long-term behavioral impact of a single low dose exposure to 4-nitrophenyl isopropyl methylphosphonate (NIMP), a sarin surrogate. We chose two different sublethal doses of NIMP, each corresponding to a fraction of the median lethal dose (one mild and one convulsive), and evaluated behavioral changes over a 6-month period following exposure. Mice exposed to both doses showed anxious behavior which persisted for six-months post-exposure. A longitudinal magnetic resonance imaging examination did not reveal any anatomical changes in the amygdala throughout the 6-month period. While no cholinesterase activity change or neuroinflammation could be observed at the latest timepoint in the amygdala of NIMP-exposed mice, important modifications in white blood cell counts were noted, reflecting a perturbation of the systemic immune system. Furthermore, intestinal inflammation and microbiota changes were observed at 6-months in NIMP-exposed animals regardless of the dose received. This is the first study to identify long-term behavioral impairment, systemic homeostasis disorganization and gut microbiota alterations following OP sublethal exposure. Our findings highlight the importance of long-term care for victims of NA exposure, even in asymptomatic cases.

Occupational risk assessment of organophosphates with an emphasis on psychological and oxidative stress factors

Organophosphate pesticides (OPPs) are widely used all over the world in domestic and industrial settings, but these chemicals affect the nervous system, induce suicidal thoughts, depression and anxiety, and impair sleep quality. The purpose of this study was to investigate the relationship between the main toxicity mechanisms of OPPs, oxidative stress and cholinesterase inhibition, and psychological parameters in chronic exposure to OPPs. This cross-sectional study was conducted on 56 male OPPs factory workers as the worker group and 47 unexposed individuals within the same age range as the control group. Psychological factors were assessed using validated questionnaires. The activity of plasma cholinesterase and oxidative stress biomarkers, total antioxidant capacity of plasma, lipid peroxidation (LPO), and protein carbonylation were determined in blood samples by spectrophotometer. Sleep quality score in the factory workers was lower, and depression and suicidal ideation scores were higher than those in the control group. These factory workers showed 35% lower levels of plasma cholinesterase activity than did the controls. Compared to the control group, a significant impairment in oxidative stress biomarkers was also observed in the workers. Meanwhile, there was a significant relationship between the duration of employment and the level of LPO as well as a significant correlation between the quality of sleep and plasma cholinesterase in the workers. In conclusion, long-term exposure to OPPs could cause oxidative damages and neurobehavioral effects. The close monitoring of workplace exposure to organophosphates pesticides and also their respective solvents along with the reduction of working hours are of the necessities to avoid the adverse impacts of exposure to these pesticides.

Hippocampal acetylcholine modulates stress-related behaviors independent of specific cholinergic inputs

Acetylcholine (ACh) levels are elevated in actively depressed subjects. Conversely, antagonism of either nicotinic or muscarinic ACh receptors can have antidepressant effects in humans and decrease stress-relevant behaviors in rodents. Consistent with a role for ACh in mediating maladaptive responses to stress, brain ACh levels increase in response to stressful challenges, whereas systemically blocking acetylcholinesterase (AChE, the primary ACh degradative enzyme) elicits depression-like symptoms in human subjects, and selectively blocking AChE in the hippocampus increases relevant behaviors in rodents. We used an ACh sensor to characterize stress-evoked ACh release, then used chemogenetic, optogenetic and pharmacological approaches to determine whether cholinergic inputs from the medial septum/diagonal bands of Broca (MSDBB) or ChAT-positive neurons intrinsic to the hippocampus mediate stress-relevant behaviors in mice. Chemogenetic inhibition or activation of MSDBB cholinergic neurons did not result in significant behavioral effects, while inhibition attenuated the behavioral effects of physostigmine. In contrast, optogenetic stimulation of septohippocampal terminals or selective chemogenetic activation of ChAT-positive inputs to hippocampus increased stress-related behaviors. Finally, stimulation of sparse ChAT-positive hippocampal neurons increased stress-related behaviors in one ChAT-Cre line, which were attenuated by local infusion of cholinergic antagonists. These studies suggest that ACh signaling results in maladaptive behavioral responses to stress if the balance of signaling is shifted toward increased hippocampal engagement.

Motor, memory, and anxiety-like behavioral impairments associated with brain-derived neurotrophic factor and dopaminergic imbalance after inhalational exposure to deltamethrin

Believed to cause damage to the nervous system and possibly being associated with neurodegenerative diseases, deltamethrin (DM) is a type II pyrethroid used in pest control, public health, home environment, and vector control. The objective of this study was to evaluate the motor, cognitive and emotional changes associated with dopaminergic and BDNF imbalance after DM exposure in rats. Sixty Wistar rats (9-10 months-old) were used, under Ethics Committee on Animal Research license (ID 19/2017). The animals were randomly divided into four groups: control (CTL, 0.9% saline), DM2 (2mg DM in 1.6mL 0.9% saline), DM4 (4mg of DM in 1.6mL of 0.9% saline), and DM8 (8mg of DM in 1.6mL of 0.9% saline). DM groups were submitted to 9 or 15 inhalations, one every 48hours. Half of the animals from each group were randomly selected and perfused 24hours after the 9th or 15th inhalation. Throughout the experiment, the animal's behavior were evaluated using catalepsy test, open field, hole-board test, Modified Elevated Plus Maze, and social interaction. At the end of the experiments, the rats were perfused transcardially and their brains were processed for Tyrosine Hydroxylase (TH) and Brain derived neurotrophic factor (BDNF) immunohistochemistries. The animals submitted to 9 inhalations of DM showed a reduction in immunoreactivity for TH in the Substantia nigra pars compacta (SNpc), ventral tegmental area (VTA), and dorsal striatum (DS) areas, and an increase in BDNF in the DS and CA1, CA3 and dentate gyrus (DG) hippocampal areas. Conversely, the animals submitted to 15 inhalations of DM showed immunoreactivity reduced for TH in the SNpc and VTA, and an increase in BDNF in the hippocampal areas (CA3 and DG). Our results indicate that the DM inhalation at different periods induce motor and cognitive impairments in rats. Such alterations were accompanied by dopaminergic system damage and a possible dysfunction on synaptic plasticity.

Recent pesticide exposure affects sleep: A cross-sectional study among smallholder farmers in Uganda

BACKGROUND

Poorly educated smallholder farmers in low-income countries are highly exposed to pesticides. This can result in adverse mental health issues, of which sleep problems might be an underlying indicator. We aim to examine the association between sleep problems and pesticide exposure among smallholder farmers in Uganda.

METHODS

A cross-sectional survey with 253 smallholder farmers was conducted between October and December 2019. Sleep problems were assessed during the week before the visit using the Medical Outcomes Study Sleep Scale (MOS-SS). Exposure to pesticides was assessed as application days of any pesticide and as use of 2,4-D, glyphosate, mancozeb, organophosphates & carbamates, pyrethroids and other pesticides during the week and year prior to the visit. Associations were assessed using adjusted multivariable logistic regression models.

RESULTS

Increased odds ratio (OR) for the sleep problem index 6-items (OR [95% Confidence Interval] 1.99 [1.04; 3.84] and 3.21 [1.33; 7.82]), sleep inadequacy (1.94 [1.04; 3.66] and 2.49 [1.05-6.22]) and snoring (3.17 [1.12; 9.41] and 4.07 [1.04; 15.14]) were observed for farmers who respectively applied pesticides up to two days and three or more days in the past week compared to farmers who did not apply during the past week. Gender-stratified analyses showed a higher OR for female applicators (4.27 [1.76-11.16]) than for male applicators (1.82 [0.91-3.79]) for the association between the sleep problem index 6-items and pesticide use in the week before the visit. Increased ORs were also observed for the association between the sleep problem index 6-item and mancozeb exposure during the past year 2.28 [1.12-4.71] and past week 2.51 [0.86-7.55] and glyphosate exposure during the past week 3.75 [1.24-11.8] compared to non-applicators.

DISCUSSION

Our findings suggest an increased risk of sleep problems among smallholder farmers in a pesticide-exposure-dependent way in a low-income context. Further gender-stratified, longitudinal investigations are warranted to confirm these findings.

The problems of women working in greenhouse agriculture in rural area in Turkey: A phenomenological study from health and social perspective

Working in agriculture may cause serious health problems due to heavy working conditions and chemical exposure. This Husserlian phenomenological qualitative study was conducted with 22 women working in greenhouse agriculture to investigate the health and social problem(s). In the evaluation of the data, Colaizzi's seven-step content analysis method and thematic analysis were used. The Kappa analysis was performed with two independent experts to measure the reliability of comparative fit, and the value obtained in the analysis was 1.00 (perfect fit). Based on the content analysis, six themes were defined. All participants indicated that they had different reproductive health-related problems. Some participants stated that their children had respiratory system-related problems and that they were subjected to physical, verbal/emotional and sexual violence by their husbands. It is important to provide health education, counselling services and screening programmes for women who work in greenhouse agriculture and thus are in the at-risk group for poor health.

A subchronic low-dose exposure of a glyphosate-based herbicide induces depressive and anxious-like behavior in mice: quercetin therapeutic approach

In this study, we investigated the possible role of pesticide exposure in contributing to neurological diseases such as depression. Here, we evaluated whether a subchronic low dose of a glyphosate-based herbicide (GBH) could induce alterations in the central nervous system, using the flavonoid quercetin as a therapeutic strategy. Forty mice were divided into four treatment groups: control, GBH, quercetin, and GBH+Quer groups and received 50 mg/kg of GBH solution, 30 mg/kg of quercetin, and/or vehicles for 30 days via gavage. After performing behavioral tests, such as the open field (OF), elevated plus maze (EPM), forced swim test (FST), and sucrose preference test (SPT), the mice were euthanized and their hippocampal tissues were collected to measure the levels of oxidative stress markers such as reactive species (RS), total antioxidant capacity (FRAP), reduced glutathione (GSH), and acetylcholinesterase activity (AChE), as well as for histological evaluation. The GBH group showed anxious and depressive-like behavior in the EPM and FST tests, as well as increased levels of RS and decreased GSH levels in the hippocampus. Quercetin treatment in the GBH+Quer group allowed partial or total improvement in behavioral tests (EPM and FST) and in the levels of oxidative stress markers (RS and GSH). However, the quercetin group showed similar behavior to the GBH group after treatment. The results revealed that oral exposure to a subchronic low dose of GBH was capable of promoting effects on behavior and oxidative stress in the hippocampus of mice. In addition, despite quercetin having a neuroprotective role, caution is needed when considering the possible per se effects of its continuous supplementation.

Persistent neuropathology and behavioral deficits in a mouse model of status epilepticus induced by acute intoxication with diisopropylfluorophosphate

Organophosphate (OP) nerve agents and pesticides are a class of neurotoxic compounds that can cause status epilepticus (SE), and death following acute high-dose exposures. While the standard of care for acute OP intoxication (atropine, oxime, and high-dose benzodiazepine) can prevent mortality, survivors of OP poisoning often experience long-term brain damage and cognitive deficits. Preclinical studies of acute OP intoxication have primarily used rat models to identify candidate medical countermeasures. However, the mouse offers the advantage of readily available knockout strains for mechanistic studies of acute and chronic consequences of OP-induced SE. Therefore, the main objective of this study was to determine whether a mouse model of acute diisopropylfluorophosphate (DFP) intoxication would produce acute and chronic neurotoxicity similar to that observed in rat models and humans following acute OP intoxication. Adult male C57BL/6J mice injected with DFP (9.5 mg/kg, s.c.) followed 1 min later with atropine sulfate (0.1 mg/kg, i.m.) and 2-pralidoxime (25 mg/kg, i.m.) developed behavioral and electrographic signs of SE within minutes that continued for at least 4 h. Acetylcholinesterase inhibition persisted for at least 3 d in the blood and 14 d in the brain of DFP mice relative to vehicle (VEH) controls. Immunohistochemical analyses revealed significant neurodegeneration and neuroinflammation in multiple brain regions at 1, 7, and 28 d post-exposure in the brains of DFP mice relative to VEH controls. Deficits in locomotor and home-cage behavior were observed in DFP mice at 28 d post-exposure. These findings demonstrate that this mouse model replicates many of the outcomes observed in rats and humans acutely intoxicated with OPs, suggesting the feasibility of using this model for mechanistic studies and therapeutic screening.

Neurobehavioral anomalies in zebrafish after sequential exposures to DDT and chlorpyrifos in adulthood: Do multiple exposures interact?

A sequence of different classes of synthetic insecticides have been used over the past 70 years. Over this period, the widely-used organochlorines were eventually replaced by organophosphates, with dichlorodiphenyltrichloroethane (DDT) and chlorpyrifos (CPF) as the principal prototypes. Considerable research has characterized the risks of DDT and CPF individually, but little is known about the toxicology of transitioning from one class of insecticides to another, as has been commonplace for agricultural and pest control workers. This study used adult zebrafish to investigate neurobehavioral toxicity following 5-week chronic exposure to either DDT or CPF, to or their sequential exposure (DDT for 5 weeks followed by CPF for 5 weeks). At the end of the exposure period, a subset of fish were analyzed for brain cholinesterase activity. Behavioral effects were initially assessed one week following the end of the CPF exposure and again at 14 months of age using a behavioral test battery covering sensorimotor responses, anxiety-like functions, predator avoidance and social attraction. Adult insecticide exposures, individually or sequentially, were found to modulate multiple behavioral features, including startle responsivity, social approach, predator avoidance, locomotor activity and novel location recognition and avoidance. Locomotor activity and startle responsivity were each impacted to a greater degree by the sequential exposures than by individual compounds, with the latter being pronounced at the early (1-week post exposure) time point, but not 3-4 months later in aging. Social approach responses were similarly impaired by the sequential exposure as by CPF-alone at the aging time point. Fleeing responses in the predator test showed flee-enhancing effects of both compounds individually versus controls, and no additive impact of the two following sequential exposure. Each compound was also associated with changes in recognition or avoidance patterns in a novel place recognition task in late adulthood, but sequential exposures did not enhance these phenotypes. The potential for chemical x chemical interactions did not appear related to changes in CPF metabolism to the active oxon, as prior DDT exposure did not affect the cholinesterase inhibition resulting from CPF. This study shows that the effects of chronic adult insecticide exposures may be relevant to behavioral health initially and much later in life, and that the effects of sequential exposures may be unpredictable based on their constituent exposures.

A Review of Nanocomposite-Modified Electrochemical Sensors for Water Quality Monitoring

Electrochemical sensors play a significant role in detecting chemical ions, molecules, and pathogens in water and other applications. These sensors are sensitive, portable, fast, inexpensive, and suitable for online and in-situ measurements compared to other methods. They can provide the detection for any compound that can undergo certain transformations within a potential window. It enables applications in multiple ion detection, mainly since these sensors are primarily non-specific. In this paper, we provide a survey of electrochemical sensors for the detection of water contaminants, i.e., pesticides, nitrate, nitrite, phosphorus, water hardeners, disinfectant, and other emergent contaminants (phenol, estrogen, gallic acid etc.). We focus on the influence of surface modification of the working electrodes by carbon nanomaterials, metallic nanostructures, imprinted polymers and evaluate the corresponding sensing performance. Especially for pesticides, which are challenging and need special care, we highlight biosensors, such as enzymatic sensors, immunobiosensor, aptasensors, and biomimetic sensors. We discuss the sensors' overall performance, especially concerning real-sample performance and the capability for actual field application.

Does the application of acetylcholinesterase inhibitors in the treatment of Alzheimer's disease lead to depression?

Introduction: Alzheimer's disease and depression are health conditions affecting millions of people around the world. Both are strongly related to the level of the neurotransmitter acetylcholine. Since cholinergic deficit is characteristic of Alzheimer's disease, acetylcholinesterase inhibitors are applied as relevant drugs for the treatment of this disease, elevating the level of acetylcholine. On the other hand, a high level of acetylcholine is found to be associated with the symptoms of clinical depression.Areas covered: This article aims to discuss if acetylcholinesterase inhibitors used as anti-Alzheimer's drugs could be the cause of the symptoms of clinical depression often linked to this neurological disorder. Emphasis will be put on drugs currently in use and on newly investigated natural products, which can inhibit AChE activity.Expert opinion: Currently, it is not proven that the patient treated for Alzheimer's disease is prone to increased risk for depression due to the acetylcholinesterase inhibition, but there are strong indications. The level of acetylcholine is not the only factor in highly complicated diseases like AD and depression. Still, it needs to be considered isolated, keeping in mind the nature of presently available therapy, especially during a rational drug design process.

Associations of acetylcholinesterase inhibition between pesticide spray seasons with depression and anxiety symptoms in adolescents, and the role of sex and adrenal hormones on gender moderation

BACKGROUND

Cholinesterase inhibitor pesticides, especially organophosphates, are endocrine disruptors and a few existing studies have linked self-reports of exposure with increased depression and anxiety. Some evidence suggests that associations may be stronger in women, but the mechanism of this gender difference is unclear. We assessed whether acetylcholinesterase (AChE) inhibition between 2 time points (reflecting greater cholinesterase inhibitor exposure) during different agricultural seasons in the year was associated with anxiety/depression symptoms.

METHODS

We examined 300 adolescents (ages 11-17y, 51% female) living near agricultural settings in Ecuador (ESPINA study) twice in 2016: April and July-October. We assessed AChE activity (finger stick), estradiol, testosterone, dehydroepiandrosterone, cortisol (saliva) and anxiety and depression scales (CDI-2 and MASC-2).

RESULTS

The mean (SD) depression and anxiety scores were 52.8 (9.3) and 58.1 (9.6), respectively. The median (25th, 75th percentile) AChE change (July-October vs April) was -3.94% (-10.45%, 5.13%). For every 10% decrease in AChE activity, there was a 0.96 unit (95%CI: 0.01, 1.90) increase in depression symptoms and an OR of elevated depression score of 1.67 (1.04, 2.66). These associations were stronger in girls (OR=2.72 [1.23, 6.00]) than boys (1.18 [0.59, 2.37]). Adjustment for cortisol, testosterone and dehydroepiandrosterone reduced gender differences by 18-62%. No associations were observed with anxiety.

DISCUSSION

Inhibition of AChE activity at 2 points in time during different pesticide spray periods was associated with greater depression symptoms, affecting girls more than boys. Gender differences may be partly explained by endocrine disruption. These findings suggest that AChE inhibition may transiently affect the mood of adolescents.

Environmental pollution and mental health: a narrative review of literature

Pollutant agents are exponentially increasing in modern society since industrialization processes and technology are being developed worldwide. Impact of pollution on public health is well known but little has been described on the association between environmental pollutants and mental health. A literature search on PubMed and EMBASE has been conducted and 134 articles published on the issue of pollution and mental health have been included, cited, reviewed, and summarized. Emerging evidences have been collected on association between major environmental pollutants (air pollutants, heavy metals, ionizing radiation [IR], organophosphate pesticides, light pollution, noise pollution, environmental catastrophes) and various mental health disorders including anxiety, mood, and psychotic syndromes. Underlying pathogenesis includes direct and indirect effects of these agents on brain, respectively, due to their biological effect on human Central Nervous System or related to some levels of stress generated by the exposure to the pollutant agents over the time. Most of emerging evidences are still nonconclusive. Further studies should clarify how industrial production, the exploitation of certain resources, the proximity to waste and energy residues, noise, and the change in lifestyles are connected with psychological distress and mental health problems for the affected populations.

AChR is partly responsible in mice depressive-like behavior after Phosalone exposure

BACKGROUND

Phosalone (Pln) is an organophosphorus pesticide acetylcholinesterase (AChE) inhibitor. Blockade of AChE amplifies ACh signaling that is related to depressive symptoms. The effects of Pln exposure were evaluated on depressive behavior in mice and the involvement of muscarinic ACh receptor (MAChR) was assessed.

MATERIAL AND METHODS

After measuring total activity in the locomotor test the immobility time during the forced swimming test (FST) in male mice was evaluated as an index of depression. Pln single dose was administered by gavage feeding and examined after 3 h (day1) and on day 7 for evaluating delayed toxicity. In separate groups Pln was administered for 5 consecutive days and examined on day 6 also after one-week delay on day12.

RESULTS

While there were only marginal differences in the locomotor tests. Immobility time during the FST significantly increased on day1 by Pln 6, 12, 40 mg/kg (185 ± 17 s, 186 ± 9 s, 172.0 ± 7 s respectively) compared with control animals (149 ± 8 s, p < 0.01), immobility time was higher than control on day 6 after multiple exposures to Pln (0.6, 6, 12, 20 mg/kg 190 ± 20s, 210 ± 4 s, 196 ± 10s, 204 ± 9 respectively, vs control 153 ± 7 p < 0.001). The immobility time remained high following a week of relapse. The co-administration of Pln with scopolamine (Scp) a MAChR antagonist reduced immobility time (141 ± 10s vs Pln 186 ± 9 s, p < 0.01).

CONCLUSION

Single exposure to Pln induced depressive-like effects that were reversed by Scp, indicating that MAChR stimulation may be involved. While cumulative exposures caused more pronounced changes in depressive behavior that remained after a week from the last exposure.

Factors Associated with Depressive Symptoms Among Rural Residents from Remote Areas

This study aimed to investigate the risk factors for depressive symptoms among rural residents in Brazil. A representative sample of two hundred eighty-eight volunteers aged from 18 to 65 years was included and determining factors for high BDI-II score were investigated through a multivariate logistic model. Sadness, loss of pleasure, crying, worthlessness and loss of interest in sex are more likely to be observed in females, and risk factors to this high depression score among rural residents were shown to be: female gender, tobacco use, pesticide application, poor self-perceived health and presence of chronic disease. These data contribute to the knowledge of factors determining depressive symptoms among rural residents and may help to expand health policies to improve quality of rural life on these communities and others with similar characteristics.

Reduced neurobehavioral functioning in agricultural workers and rural inhabitants exposed to pesticides in northern Chile and its association with blood biomarkers inhibition

BACKGROUND

Previous biomonitoring studies have shown that people in the rural population of Coquimbo, the major agricultural area in northern Chile are being occupationally and environmentally exposed to organophosphate/carbamate (OP/CB) pesticides. Given their harmful effects, this study had two aims; first, to evaluate the effect of cumulative or chronic exposure to OP/CB pesticides on the neurobehavioral performance of agricultural workers and rural inhabitants; second, to determine if changes in the neurobehavioral performance are associated to changes in blood biomarkers of OP/CB pesticides during the spray season, when exposure is higher.

METHODS

For the first aim, a cross sectional study of neurobehavioral performance in adult volunteers (men and women, 18-50 years-old, right-handed) was carried out in the pre-spray season. Sampling was done by convenience and a questionnaire was used to categorize participants depending on their level of chronic exposure, as either: occupationally exposed (OE, n = 87), environmentally exposed (EE, n = 81), or non-exposed controls or reference group (RG, n = 100). A neurobehavioral test battery consisting of 21 tests to measure cognitive, motor and emotional state was applied. For the second aim, neurobehavioral measures were taken a second time from EE and OE groups during the spray season, and their exposure corroborated by blood-based biomarker inhibition.

RESULTS

Lower neurobehavioral performance was observed in the pre-spray evaluation of EE and OE groups compared to the non-exposed, OE being the worst performing group. Seasonal exposure impaired performance in both exposure groups on all tests except those on attention and mood. Data modeling of the basal (pre-spray) measurements showed that the level of exposure was the best predictor of performance. During spraying, inhibition of BChE activity in the EE group was the best predictor of low performance in tests measuring logical, auditory and visual memory, inhibitory control of cognitive interference, constructional and planning abilities, executive functions, and motor speed and coordination.

CONCLUSION

Long-term occupational or environmental exposure to pesticides caused impairment in neurobehavioral functioning, which worsened during the spraying season, mainly in EE. BChE inhibition was the best predictor for seasonal neurobehavioral changes in EE.

Identification of markers of depression and neurotoxicity in pesticide exposed agriculture workers

Earlier, we reported that chronic exposure to pesticides causes a reduction in the acetylcholinesterase activity and hematological and biochemical alterations in agriculture workers. In continuation with that, the present study aimed to investigate the pesticide-induced neurochemical imbalance and its association with behavior alterations in agricultural workers. A significant increase in depressive symptoms, assessed by the Beck Depression Inventory-II was observed in pesticide exposed workers as compared to the unexposed. A decrease in the level of dopamine in plasma and levels of dopamine, 3,4-dihydroxyphenylacetic acid, homovanillic acids, norepinephrine, serotonin, and hydroxyindoleacetic acid in urine was also observed. An increase in the levels of MAO-A and MAO-B has also been observed in these individuals. The decreased levels of neurotransmitters in the blood and urine have been linked with increased levels of MAO and pesticide residues in plasma and urine. Furthermore, these changes were associated with a higher incidence of depression in agricultural workers.

Youth working in tobacco farming: effects on smoking behavior and association with health status

BACKGROUND

Cultivation of tobacco raises concerns about detrimental health and social consequences for youth, but tobacco producing countries only highlight economic benefits. We compared sociodemographic and health-related characteristics of school-age youth who worked and did not work in tobacco farming and assessed the effects on smoking behavior and health at 1 year.

METHODS

We used existing data collected in the province of Jujuy, Argentina where 3188 youth 13 to 17 years of age from a random middle school sample responded to longitudinal questionnaires in 2005 and 2006. Multivariate logistic regression models predicted association of tobacco farming work with health status and smoking behavior at 1 year.

RESULTS

22.8% of youth in the tobacco growing areas of the province were involved in tobacco farming. The mean age of initiation to tobacco farming was 12.6 years. Youth working in farming had higher rates of fair or poor versus good or excellent self-perceived health (30.3% vs. 19.0%), having a serious injury (48.5% vs. 38.5%), being injured accidentally by someone else (7.5% vs. 4.6%), being assaulted (5.5% vs. 2.6%), and being poisoned by exposure to chemicals (2.5% vs. 0.7%). Youth working in tobacco farming also had higher prevalence of ever (67.9% vs. 55.2%), current (48.0% vs. 32.6%) and established smoking (17.8% vs. 9.9%). In multivariate logistic regression models tobacco farming in 2005 was associated with significant increased reporting of serious injury (OR = 1.4; 95%CI 1.1-2.0), accidental injury by someone else (OR = 1.5; 95% 1.0-2.1), assault (OR = 2.2; 95% CI 1.3-3.8), and poisoning by exposure to chemicals (OR = 2.5; 95% CI 1.2-5.4). Tobacco farming in 2005 predicted established smoking 1 year later (OR = 1.5; 95% CI 1.1-2.0).

CONCLUSION

Youth who work in tobacco faming face a challenging burden of adversities that increase their vulnerability. Risk assessments should guide public policies to protect underage youth working in tobacco farming. (298 words).

Exposição a agrotóxicos e agravos à saúde em trabalhadores agrícolas: o que revela a literatura?

Resumo Introdução: a relação entre agrotóxicos e agravos à saúde tem sido investigada em diferentes contextos. Objetivo: reunir evidência científica relevante sobre agravos à saúde associados à exposição ocupacional aos agrotóxicos. Métodos: revisão de literatura de estudos publicados entre 2000 e 2017, nas bases PubMed, Embase e LILACS. Estabeleceu-se como critérios de elegibilidade: a) estudos observacionais; b) população de trabalhadores agrícolas; c) exposição ocupacional; d) agravos à saúde definidos como desfecho; e) comparação estatística de expostos com não expostos; f) idioma inglês, português ou espanhol. Resultados: 59 publicações foram elegíveis - 33 estudos transversais, 22 de coorte e 4 caso-controle. Discussão: os estudos indicam que trabalhadores rurais apresentam maior risco para alguns agravos crônicos (câncer, doenças mentais, neurológicas, endócrinas, renais, auditivas, respiratórias e autoimunes), efeitos subclínicos (danos genéticos e alterações bioquímicas) e sinais e sintomas clínicos de intoxicação aguda. Também foram identificadas limitações dos estudos quanto à avaliação da exposição e do desfecho, delineamento e amostragem. Conclusão: as evidências sugerem a necessidade de se complementar a avaliação da saúde dos trabalhadores expostos aos agrotóxicos utilizando biomarcadores de efeito de genotoxicidade e citotoxicidade, a fim de promover e ampliar a vigilância da exposição e das intoxicações crônicas e suas prevenções.

Key Risk Factors Affecting Farmers' Mental Health: A Systematic Review

Recently, concern has increased globally over farmers' mental health issues. We present a systematic review of the outcomes, locations, study designs, and methods of current studies on farmers' mental health. In particular, this review aims to fill an important gap in understanding of the potential key risk factors affecting farmers' mental health around the world. 167 articles on farmer mental health were included in a final systematic review using a standardized electronic literature search strategy and PRISMA guidelines. The four most-cited influences on farmers' mental health in the reviewed literature respectively were pesticide exposure, financial difficulties, climate variabilities/drought, and poor physical health/past injuries. The majority of studies were from developed countries, most specifically from the United States, Australia, and the United Kingdom. Comparative studies on the mental health of farmers and other occupational workers showed mixed results, with a larger portion identifying that psychological health disturbances were more common in farmers and farm-workers. Knowledge of farmer psychological disorder risk factors and its impacts are essential for reducing the burden of mental illness. Further research will be required on climate change impacts, developing country farmers' mental health, and information on how to reduce help-seeking barriers amongst farmers.

DNA damage and adverse neurological outcomes among garlic farmers exposed to organophosphate pesticides

Garlic farmers used organophosphate pesticides to control insects, resulting in an increased risk for adverse health outcomes. Thus, we investigated exposure to organophosphate pesticides, DNA damage, nerve conduction, and neurological symptoms among 134 garlic farmers. They were interviewed, measured nerve conduction, and collected blood and urine for determining DNA damage and dialkylphosphate metabolites. Total dialkylphosphate levels of farmers who began cultivating garlic in October were significantly higher than those of non-farmers and the farmers who began cultivating in November and December. Farmers showed significantly longer comet tail lengths and tail moments than non-farmers. However, their mean compound motor and sensory nerve action potential amplitudes of the median, ulnar, and common peroneal nerves were within normal ranges. Measurement of DNA damage is useful as a biomarker of long-term and low-level exposure to organophosphate pesticides; however, electromyography might be not sufficiently sensitive to detect nerve conduction effects in farmers exposed to pesticides.

Exploring the Drivers of Irrigator Mental Health in the Murray–Darling Basin, Australia

There has been little work conducted on how landholders’ farm management approaches and financial capital (specifically (i) farm method such as organic farming and (ii) financial profitability) may impact mental health. In particular, there is emerging evidence that an increase in natural farm capital and environmental conditions may improve farmers’ wellbeing. We used a 2015–2016 survey, which randomly sampled 1000 irrigators from the southern Murray–Darling Basin, to model the drivers of irrigators’ psychological distress. Results highlight that worsening financial capital (namely, lower farmland value, higher farm debt, lower percentage of off-farm income, lower productivity change over the past five years, and lower net farm income) was the most statistically significant factor associated with increased irrigator distress. In addition, there was some evidence that being a certified organic irrigator was also associated with lower psychological distress; however, it was only weakly significant in our overall model, with the most significance within the horticultural industry model. Contrary to expectations, drought and water scarcity were not the main drivers of psychological distress in the time-period studied, with their influence seemingly through reducing financial capital as a whole.

Microbiota and organophosphates

Organophosphates (OPs) are important toxic compounds commonly used for a variety of purposes in agriculture, industry and household settings. Consumption of these compounds affects several central nervous system functions. Some of the most recognised consequences of organophosphate pesticide exposure in humans include neonatal developmental abnormalities, endocrine disruption, neurodegeneration, neuroinflammation and cancer. In addition, neurobehavioral and emotional deficits following OP exposure have been reported. It would be of great value to discover a therapeutic strategy which produces a protective effect against these neurotoxic compounds. Moreover, a growing body of preclinical data suggests that the microbiota may affect metabolism and neurotoxic outcomes through exposure to OPs. The human gut is colonised by a broad variety of microorganisms. This huge number of bacteria and other microorganisms which survive by colonising the gastrointestinal tract is defined as "gut microbiota". The gut microbiome plays a profound role in metabolic processing, energy production, immune and cognitive development and homeostasis. The effects are not only localized in the gut, but also influence many other organs, such as the brain through the microbiome-gut-brain axis. Therefore, given the gut microbiota's key role in host homeostasis, this microbiota may be altered or modified temporarily by factors such as antibiotics, diet and toxins such as pesticides. The aim of this review is to examine scientific articles concerning the impact of microbiota in OP toxicity. Studies focussed on the possible contribution the microbiota has on variable host pharmacokinetic responses such as absorption and biotransformation of xenobiotics will be evaluated. Microbiome manipulation by antibiotic or probiotic administration and faecal transplantation are experimental approaches recently proposed as treatments for several diseases. Finally, microbiota manipulation as a possible therapeutic strategy in order to reduce OP toxicity will be discussed.

An educational intervention on the risk perception of pesticides exposure and organophosphate metabolites urinary concentrations in rural school children in Maule Region, Chile

BACKGROUND

Organophosphate (OP) pesticides can be hazardous to human health if not applied with appropriate precautions. There is evidence in the Maule region of Chile that rural schoolchildren are exposed to OP pesticides.

OBJECTIVE

To evaluate the effectiveness of an educational intervention on OP exposure and understanding of pesticides and their hazards (risk perception) in two school communities in the Maule Region of Chile during 2016.

METHOD

We conducted a quasi-experimental study about the effects on OP pesticide exposure of a community outreach and education program (COEP) administered in four 2-h sessions that's included hands-on activities among 48 schoolchildren from two rural schools. The intervention was directed to groups of parents and school-children separately, and aimed to educate them about the risks of exposure to pesticides and their effects on health. We measured 3,5,6-trichloro-2-pyridinol (TCPy), 2-isopropyl-4-methyl-6-hydroxypyrimidine (IMPY), malathion dicarboxylic acid (MDA), p-nitrophenol (PNP), specific urinary metabolites of the OP pesticides chlorpyrifos, diazinon, malathion and parathion, respectively, as well as the non-specific diethylakylphosphates (DEAPs) and dimethylalkylphosphates (DMAPs) in 192 urine samples of schoolchildren collected before and after the intervention. The risk perception of school children and their parents was also assessed through a questionnaire before and after the intervention. Generalized Estimated Equations were used to account for each child's repeated measures during four sessions, two in September 2016 (pre-intervention) and two in November 2016 (post-intervention).

RESULTS

The intervention level had significant effect on the risk perception of adults and children, which increased after the intervention. However, the intervention was not associated with reduced of urinary metabolites levels, with no significant differences between the pre and post measures. The detection frequencies were 1.1% (MDA), 71.4% (TCPy), 43.3% (IMPY), 98.96% (PNP), and 100% (DEAPs and DMAPs). Higher DEAPs urine concentrations were associated with eating more fruit at school (p = 0.03), a younger age (p = 0.03), and being male (p = 0.01). DMAPs showed no associations with potential predictor variables (e.g. OPs applied at home, fruit consumption at school, among others). Higher TCPy was associated with attending a school closer to farms (p = 0.04) and living in a home closer to farm fields (p = 0.01); higher PNP was marginally associated with children younger age (p = 0.035).

CONCLUSION

Environmental exposure to OP pesticides was unchanged even after behavior changes. It is possible that a longer time period is needed to observe changes in both behavior and urinary metabolites. The levels of DEP and DMP metabolites found here are above the reference population of the US, and our findings indicate exposure to a wide variety of OP pesticides. Given that individual-level interventions were not associated with lower exposures, efforts to reduce exposure must occur upstream and require stricter regulation and control of pesticide use by government agencies.

Associations of acetylcholinesterase activity with depression and anxiety symptoms among adolescents growing up near pesticide spray sites

BACKGROUND

The cholinergic system has an important role in mood regulation. Cholinesterase inhibitor pesticides (e.g. organophosphates) appear to increase depression and anxiety symptoms in the few existing animal and human studies. Human studies have not described such associations using biomarkers of exposure and studies among children are needed.

METHODS

We studied 529 adolescents (ages 11-17y) in agricultural communities in the Ecuadorian Andes (ESPINA study). Acetylcholinesterase (AChE) activity was measured in a finger-stick sample. Anxiety and depression symptoms were assessed using the CDI-2 and MASC-2 (greater scores reflect greater internalizing symptoms). Models adjusted for age, gender, hemoglobin, income among others.

RESULTS

The median age was 14.38y and 51% were female. The mean (SD) of the following parameters were: AChE 3.7 U/mL (0.55), depression T-score 53.0 (9.4) and anxiety T-score: 57.6 (9.8). Lower AChE activity (reflecting greater cholinesterase inhibitor exposure) was associated with higher depression symptoms (difference per SD decrease of AChE [β [95% CI:]]: 1.09 [0.02, 2.16]), was stronger among girls (β = 1.61) than boys (β = 0.69), and among younger (<14.38y, β = 1.61) vs. older children (β = 0.57). The associations were strongest among girls <14.38y (β = 3.30 [0.54, 6.05], OR for elevated symptoms per SD decrease in AChE = 2.58 [1.26, 5.27]). No associations were observed with anxiety scores. Analyses of AChE change between 2008 and 2016 concurred with these findings.

DISCUSSION

We observed associations between a biomarker of pesticide exposure and children's depression symptoms. Lower AChE activity may create risk for depression in teenagers, particularly among girls during early adolescence.