Asthma associated with pesticide exposure among women in rural Western Cape of South Africa

The impact of outdoor pollution and extreme temperatures on asthma-related outcomes: A systematic review for the EAACI guidelines on environmental science for allergic diseases and asthma

Air pollution is one of the biggest environmental threats for asthma. Its impact is augmented by climate change. To inform the recommendations of the EAACI Guidelines on the environmental science for allergic diseases and asthma, a systematic review (SR) evaluated the impact on asthma-related outcomes of short-term exposure to outdoor air pollutants (PM2.5, PM10, NO2, SO2, O3, and CO), heavy traffic, outdoor pesticides, and extreme temperatures. Additionally, the SR evaluated the impact of the efficacy of interventions reducing outdoor pollutants. The risk of bias was assessed using ROBINS-E tools and the certainty of the evidence by using GRADE. Short-term exposure to PM2.5, PM10, and NO2 probably increases the risk of asthma-related hospital admissions (HA) and emergency department (ED) visits (moderate certainty evidence). Exposure to heavy traffic may increase HA and deteriorate asthma control (low certainty evidence). Interventions reducing outdoor pollutants may reduce asthma exacerbations (low to very low certainty evidence). Exposure to fumigants may increase the risk of new-onset asthma in agricultural workers, while exposure to 1,3-dichloropropene may increase the risk of asthma-related ED visits (low certainty evidence). Heatwaves and cold spells may increase the risk of asthma-related ED visits and HA and asthma mortality (low certainty evidence).

Obstructive Lung Disease Linked to Occupational Exposures in Malawian Tobacco Farmers

Nicotine and pesticide exposure in agricultural settings have been linked to the development of chronic respiratory disease in workers. However, this has not been extensively studied in Africa. The aim of this study was therefore to determine the prevalence of obstructive lung disease and its relationship to concurrent nicotine and pesticide exposure among small-scale tobacco farmers in Malawi. For this purpose, sociodemographic characteristics, occupational and environmental exposures were evaluated in relation to work-related respiratory symptoms and lung function impairment. A cross-sectional study was conducted enrolling 279 workers in flue-cured tobacco farms in Zomba, Malawi. The study instruments used for assessing the health outcomes were a standardised European Community Respiratory Health Survey II (ECRHS) questionnaire and Spirometry testing. The questionnaires were aimed at collecting relevant data on sociodemographic factors and self-reported respiratory health outcomes. Data were also collected on potential pesticide and nicotine exposures. Spirometry was done to evaluate objective respiratory impairment in accordance with American Thoracic Society guidelines. The mean age of participants was 38 years with 68% being male. The prevalence of work-related ocular nasal symptoms, chronic bronchitis, and work-related chest symptoms was 20%, 17%, and 29%, respectively. Airflow limitation (FEV1/FVC <70%) was found in 8% of workers. Self-reported exposure to pesticides varied from 72%- to 83%, whilst the prevalence of recent green tobacco sickness was 26%. Tasks linked to nicotine exposure, such as sowing (OR: 2.5; CI 1.1-5.7) and harvesting (OR: 2.6; CI 1.4-5.1), were significantly associated with work-related chest symptoms. Pesticide application (OR:1.96; CI 1.0-3.7) was associated with an increased risk of work-related oculonasal symptoms. Duration of pesticide exposure was also associated with obstructive impairment FEV1/FVC Collapse

Key Words

• Obstructive lung disease
• nicotine
• pesticides
• tobacco farming

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MESH Headings

• Humans
• Male
• Adult
• Female
• Tobacco
• Farmers
• Nicotine
• Cross-Sectional Studies
• Risk Factors
• Occupational Exposure/adverse effects
• Pesticides/adverse effects
• Spirometry
• Lung Diseases, Obstructive/chemically induced
• Lung
• Prevalence

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Grants

• D43 TW009609 FIC NIH HHS

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Affiliation(s)

Yotam M Moyo Occupational Medicine Division and Centre for Environmental and Occupational Health Research, School of Public Health and Family Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
Mohamed F Jeebhay Occupational Medicine Division and Centre for Environmental and Occupational Health Research, School of Public Health and Family Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
Roslynn Baatjies Occupational Medicine Division and Centre for Environmental & Occupational Health Research, School of Public Health, University of Cape Town, Cape Town, South Africa Department of Environmental and Occupational Studies, Faculty of Applied Sciences, Cape Peninsula University of Technology (CPUT), Cape Town, South Africa
Sufia Dadabhai Department of Epidemiology, Johns Hopkins School of Public Health, Baltimore, USA
Shahieda Adams Occupational Medicine Division and Centre for Environmental and Occupational Health Research, School of Public Health and Family Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa

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A cross-sectional analysis of medical conditions and environmental factors associated with fractional exhaled nitric oxide (FeNO) in women and children from the ISA birth cohort, Costa Rica

BACKGROUND

Fractional exhaled nitric oxide (FeNO) is a marker of airway inflammation. Elevated FeNO has been associated with environmental exposures, however, studies from tropical countries are limited. Using data from the Infants' Environmental Health Study (ISA) birth cohort, we evaluated medical conditions and environmental exposures' association with elevated FeNO.

METHODS

We performed a cross-sectional analysis of 277 women and 293 8-year old children who participated in the 8-year post-partum visit in 2019. We measured FeNO and collected information on medical conditions and environmental exposures including smoke from waste burning, work in banana plantations, and home pesticide use. We defined elevated FeNO as >25 ppb for women and >20 ppb for children. To evaluate factors associated with elevated FeNO, we used logistic regression models adjusted for obesity in women and unadjusted in children.

RESULTS

Overall elevated FeNO was common (20% of women, 13% of children). Rhinitis diagnosis was significantly associated with elevated FeNO in both women (odds ratio (OR): 3.67 95% Confidence Interval (CI): 1.81,7.35) and children (OR: 8.18 95%CI: 3.15, 21.22); wheeze was associated with elevated FeNO in women (OR: 4.50 95% CI: 2.25, 8.99). Environmental exposures were associated with elevated FeNO, but not significantly. Waste burning was associated with elevated FeNO in both women (OR: 1.58 95%CI 0.68, 4.15) and children (OR: 2.49 95%CI:0.82, 10.79). Para-occupational pesticide exposures were associated with elevated FeNO in women and children. For women, having a partner working in agriculture was associated with elevated FeNO (OR: 1.61 95%CI:0.77, 3.58) and for children, maternal work in agriculture was associated with elevated FeNO. (OR 2.08 95%CI 0.86, 4.67) CONCLUSION: Rhinitis and wheeze were associated with elevated FeNO in this rural, agricultural population. Smoke from waste burning as well as para-occupational pesticide exposure may contribute to elevated FeNO in rural communities.

Impacts of Agricultural Pesticide Contamination: An Integrated Risk Assessment of Rural Communities of Eswatini

Marked reductions in mean annual rainfall associated with climate change in Eswatini in Southern Africa have encouraged the recycling of irrigation water and the increased use of pesticides in agricultural production, raising concerns about potential ecological and health risks due to long-term exposure to pesticide residues in soil and irrigation water. This probabilistic integrated risk assessment used liquid chromatography with tandem mass spectrometry to analyze the concentrations of four commonly used agricultural pesticides (ametryn, atrazine, pendimethalin, and 2,4-dichlorophenoxyacetic acid (2,4-D)) in irrigation water and topsoil samples from farmlands in Eswatini to assess potential ecological and health risks due to exposure. The concentrations of these pesticides ranged from undetectable to 0.104 µg/L in irrigation water and from undetectable to 2.70 µg/g in soil. The probabilistic multi-pathway and multi-route risk assessments conducted revealed hazard indices exceeding 1.0 for all age groups for ametryn and atrazine, suggesting that the daily consumption of recycled irrigation water and produce from the fields in this area may pose considerable health risks. The indices pertaining to ecological risks had values less than 0.1. Adaptation measures are recommended to efficiently manage pesticide use in agriculture, and further research will ensure that agriculture can adapt to climate change and that the general public and ecosystem are protected.

The Association Between Urinary Concentrations of Organophosphate Metabolites and Asthma-Related Outcomes Among Schoolchildren From Informal Settlements

Objectives: There is inconsistent evidence on the relationship between pesticide exposure and childhood respiratory outcomes in non-agricultural settings. This study investigated the association between organophosphate (OP) pesticide exposure and asthma-related outcomes in children residing in four informal settlements. Methods: The study was a longitudinal study of 590 schoolchildren, with a 12 months follow-up period. A standardised questionnaire adopted from the International Study of Asthma and Allergies in Childhood was administered to caregivers for child's respiratory symptoms and household characteristics. Spirometry and fractional-exhaled nitric oxide, including a phadiatop test (atopy status) and urinary dialkyl phosphate (DAP) metabolites were measured at baseline and follow-up. DAP metabolites included diethylphosphate (DEP) and dimethyl phosphate (DMP) measured at baseline and follow-up and dimethylthiophosphate (DMTP) measured only at baseline. Results: The mean ages of schoolchildren were 9.9 ± 0.91 years and the overal incidence proportions of new doctor diagnosed asthma was 2.2%. No consistent patterns of increased risk of asthma outcomes with increasing DAP concentrations was found in multivariate analysis. Conclusion: Future studies with longer follow-up periods and repeated OP biomonitoring are recommended.

Biomarkers of organophosphate insecticides exposure and asthma in general US adults: findings from NHANES 1999-2018 data

The limited evidence linking exposure to organophosphate insecticides (OPIs) and asthma in the general population prompted us to investigate this association. Our study focused on US adults and utilized representative samples from the National Health and Nutrition Examination Survey (NHANES). From the 7 NHANES waves (1999-2018), we detected OPIs exposure using the urinary concentrations of six metabolites of dialkyl phosphates (DAPs). To evaluate the relationship between these OPIs and asthma, we employed three statistical methods: survey-multivariable logistic regression (SMLR), generalized weighted quantile sum (WQS) regression, and Bayesian kernel machine regression (BKMR). Stratified analyses were done based on the relevant variable subgroups, and sensitivity analyses were carried out to evaluate the robustness of findings. A total of 6009 adults aged from 20 to 85 years old, representing the 313.5 million adults in the non-institutionalized US population, were included in our analyses. Among them, 842 participants were determined as asthma patients with an age-adjusted prevalence of 14.2%. Our results showed that dimethyl phosphate (DMP) (adjusted odd ratio (AOR) = 1.471, 95% CI: 1.086, 1.993), diethyl phosphate (DEP) (AOR = 1.453, 95% CI: 1.118, 1.888), dimethyl thiophosphate (DMTP) (AOR = 1.454, 95% CI: 1.071, 1.973), and dimethyl dithiophosphate (DMDTP) (AOR = 1.478, 95% CI: 1.119, 1.953) had a positive correlation with asthma in adults. This association was stronger in females, non-Hispanic White populations and those with a small amount of physical activity. Our study findings indicated that exposure to OPIs may elevate the risk of asthma in US general adults. Specifically, females, individuals from non-Hispanic White backgrounds, and those with lower levels of physical activity are more susceptible to developing asthma when exposed to OPIs.

Pesticides and Their Impairing Effects on Epithelial Barrier Integrity, Dysbiosis, Disruption of the AhR Signaling Pathway and Development of Immune-Mediated Inflammatory Diseases

The environmental and occupational risk we confront from agricultural chemicals increases as their presence in natural habitats rises to hazardous levels, building a major part of the exposome. This is of particular concern in low- and middle-income countries, such as Brazil, known as a leading producer of agricultural commodities and consumer of pesticides. As long as public policies continue to encourage the indiscriminate use of pesticides and governments continue to support this strategy instead of endorsing sustainable agricultural alternatives, the environmental burden that damages epithelial barriers will continue to grow. Chronic exposure to environmental contaminants in early life can affect crucial barrier tissue, such as skin epithelium, airways, and intestine, causing increased permeability, leaking, dysbiosis, and inflammation, with serious implications for metabolism and homeostasis. This vicious cycle of exposure to environmental factors and the consequent damage to the epithelial barrier has been associated with an increase in immune-mediated chronic inflammatory diseases. Understanding how the harmful effects of pesticides on the epithelial barrier impact cellular interactions mediated by endogenous sensors that coordinate a successful immune system represents a crucial challenge. In line with the epithelial barrier hypothesis, this narrative review reports the available evidence on the effects of pesticides on epithelial barrier integrity, dysbiosis, AhR signaling, and the consequent development of immune-mediated inflammatory diseases.

Allergic and non-allergic wheeze among farm women in the Agricultural Health Study (2005-2010)

BACKGROUND

Farms represent complex environments for respiratory exposures including hays, grains and pesticides. Little is known about the impact of these exposures on women's respiratory health. We evaluated the association of farm exposures with allergic and non-allergic wheeze among women in the Agricultural Health Study, a study of farmers and their spouses based in Iowa and North Carolina.

METHODS

We used self-reported data (2005-2010) on current use (≤12 months) of 15 pesticides (selected based on frequency of use) and occupational farm activities from 20 164 women. We defined allergic wheeze as reporting wheeze and doctor-diagnosed hay fever (7%) and non-allergic wheeze as wheeze but not hay fever (8%) in the past 12 months. Using polytomous logistic regression, we evaluated associations of wheeze subtypes with pesticides and other farm exposures (eg, raising farm animals) using no wheeze/hay fever as the referent, adjusting for age, body mass index, state, current asthma, glyphosate use and smoking.

RESULTS

Current use of any pesticide, reported by 7% of women, was associated with both allergic (OR: 1.36, 95% CI: 1.10 to 1.67) and non-allergic (OR: 1.25, 95% CI: 1.04 to 1.51) wheeze. Four pesticides were associated with at least one wheeze subtype: glyphosate, with both wheeze subtypes; diazinon and fly spray with only allergic wheeze; carbaryl with only non-allergic wheeze. Working weekly with mouldy hay was associated with allergic (OR: 1.88, 95% CI: 1.26 to 2.80) and non-allergic wheeze (OR: 1.69, 95% CI: 1.18 to 2.42).

CONCLUSION

Use of specific pesticides and certain farm activities may contribute to wheeze among farm women.

Seasonal variations in air concentrations of 27 organochlorine pesticides (OCPs) and 25 current-use pesticides (CUPs) across three agricultural areas of South Africa

For decades pesticides have been used in agriculture, however, the occurrence of legacy organochlorine pesticides (OCPs) and current-use pesticides (CUPs) is poorly understood in Africa. This study investigates air concentrations of OCPs and CUPs in three South African agricultural areas, their spatial/seasonal variations and mixture profiles. Between 2017 and 2018, 54 polyurethane foam-disks passive air-samplers (PUF-PAS) were positioned in three agricultural areas of the Western Cape, producing mainly apples, table grapes and wheat. Within areas, 25 CUPs were measured at two sites (farm and village), and 27 OCPs at one site (farm). Kruskal-Wallis tests investigated area differences in OCPs concentrations, and linear mixed-effect models studied differences in CUPs concentrations between areas, sites and sampling rounds. In total, 20 OCPs and 16 CUPs were detected. A median of 16 OCPs and 10 CUPs were detected per sample, making a total of 11 OCPs and 24 CUPs combinations. Eight OCPs (trans-chlordane, o,p'-/p,p'-dichlorodiphenyldichloroethylene (DDE)/dichlorodiphenyltrichloroethane (DDT), endosulfan sulfate, γ-hexachlorocyclohexane and mirex) and two CUPs (carbaryl and chlorpyrifos) were quantified in all samples. p,p'-DDE (median 0.14 ng/m³) and chlorpyrifos (median 0.70 ng/m³) showed the highest concentrations throughout the study. Several OCPs and CUPs showed different concentrations between areas and seasons, although CUPs concentrations did not differ between sites. OCPs ratios suggest ongoing chlordane use in the region, while DDT and endosulfan contamination result from past-use. Our study revealed spatial and seasonal variations of different OCPs and CUPs combinations detected in air. Further studies are needed to investigate the potential cumulative or synergistic risks of the detected pesticides.

Environmental exposures contribute to respiratory and allergic symptoms among women living in the banana growing regions of Costa Rica

OBJECTIVES

This research evaluates whether environmental exposures (pesticides and smoke) influence respiratory and allergic outcomes in women living in a tropical, agricultural environment.

METHODS

We used data from 266 mothers from the Infants' Environmental Health cohort study in Costa Rica. We evaluated environmental exposures in women by measuring seven pesticide and two polycyclic aromatic hydrocarbons metabolites in urine samples. We defined 'high exposure' as having a metabolite value in the top 75th percentile. We collected survey data on respiratory and allergic outcomes in mothers as well as on pesticides and other environmental exposures. Using logistic regression models adjusted for obesity, we assessed the associations of pesticide exposure with multiple outcomes (wheeze, doctor-diagnosed asthma, high (≥2) asthma score based on symptoms, rhinitis, eczema and itchy rash).

RESULTS

Current pesticide use in the home was positively associated with diagnosed asthma (OR=1.99 (95% CI=1.05 to 3.87)). High urinary levels of 5-hydroxythiabendazole (thiabendazole metabolite) and living in a neighbourhood with frequent smoke from waste burning were associated with a high asthma score (OR=1.84 (95%CI=1.05 to 3.25) and OR=2.31 (95%CI=1.11 to 5.16), respectively). Women who worked in agriculture had a significantly lower prevalence of rhinitis (0.19 (0.01 to 0.93)), but were more likely to report eczema (OR=2.54 (95%CI=1.33 to 4.89)) and an itchy rash (OR=3.17 (95%CI=1.24 to 7.73)).

CONCLUSIONS

While limited by sample size, these findings suggest that environmental exposure to both pesticides and smoke may impact respiratory and skin-related allergic outcomes in women.

A snapshot of exhaled nitric oxide and asthma characteristics: experience from high to low income countries

Nitric oxide is a gas produced in the airways of asthmatic subjects and related to T2 inflammation. It can be measured as fractional nitric oxide (FeNO) in the exhaled air and used as a non-invasive, easy to evaluate, rapid marker. It is now widely used in many settings to determine airway inflammation. The aim of this narrative review is to report relationship between FeNO and the physiopathologic characteristics of asthmatic patients. Factors affecting FeNO levels have also been analysed as well as the impact of corticosteroid, target therapies and rehabilitation programs. Considering the availability of the test, spreading this methodology to low income countries has also been considered as a possibility for evaluating airway inflammation and monitoring adherence to inhaled corticosteroid therapy. PubMed data search has been performed restricted to English language papers. Research was limited to studies in adults unless studies in children were the only ones reported for a particular issue. This revision could be useful to summarize the role of FeNO in relation to asthma characteristics and help in the use of FeNO in different clinical settings particularly in low income countries.

Immune response of Brazilian farmers exposed to multiple pesticides

Occupational exposure to pesticides has been identified as a factor that predisposes to disorders of the immune system. Immunosuppression, autoimmunity, cancer of various organs and other diseases in people who apply these products have been reported by the studies. This study aimed to investigate the relationship between occupational exposure to pesticides and the immunological profile in 43 farmers exposed to mixtures of pesticides for at least 15 years. A control group composed of 30 individuals without a history of occupational exposure to pesticides was also evaluated. Peripheral blood samples were processed by flow cytometry and cells were labelled with an 8-color monoclonal antibody panel. Plasma cytokines were also measured. Significant increase in classical monocytes (p < 0.001) and dendritic cells (p < 0.001) in the exposed group was observed as well in total T cells (p = 0.04), central memory CD8 T cells (p = 0.02) and effector memory CD8 T cells (p = 0.01). On the other hand, the activation markers of T cells as the expression of CD57, HLA-DR, CD25 and CD28 were evaluated and no difference was found between groups. When the B cells were analyzed, a significant decrease in total B cells (p = 0.01), regulatory B cells (p < 0.001) and plasmablasts (p < 0.001) in the exposed group, compared to healthy controls, was observed. Pro-inflammatory IL-6 was significantly elevated (p = 0.04) in the plasma of farmers compared to that of controls. The constant antigenic stimulus that occurs during exposure to pesticides can favor the recruitment of dendritic cells and macrophages (APCs) presents in the skin and respiratory tract. In the secondary lymphoid organs, the CD4 T and B cells that process such antigens are possibly undergoing proliferative exhaustion, with the consequent depletion of all mature B subpopulations. The resulting drop in humoral immunity may be offset by an increase in the number of circulating CD8 T lymphocytes due to their cytotoxic action.

Global trends in pesticides: A looming threat and viable alternatives

Pesticides are widely used chemical compounds in agriculture to destroy insects, pests and weeds. In modern era, they form an indispensable part of agricultural and health practices. Globally, nearly 3 billion kg of pesticides are used every year with a budget of ~40 billion USD. This extensive usage has increased the crop yield as well as led to significant reduction in harvest losses and thereby, enhanced food availability. On the other hand, indiscriminate usage of these chemicals has led to several environmental implications and caused adverse effects on human health. Epidemiological evidences have revealed the harmful effects of pesticides exposure on various organs including liver, brain, lungs and colon. Recent investigations have shown that pesticides can also lead to fatal consequences such as cancer among individuals. These chemicals enter ecosystem, thus hampering the sensitive environmental equilibrium through bio-accumulation. Due to their non-biodegradable nature, they can persist in nature for years and are regarded as potent biohazard. Worldwide, very few surveillance methods have been considered, which can bring awareness among the individuals, therefore the present review is an attempt to delineate consequences induced by various types of pesticide exposure on the environment. Further, the prospective of biopesticides use could facilitate the increase of crop production without compromising human health.

Allergic Anaphylactic Risk in Farming Activities: A Systematic Review

Allergic disorders in the agriculture sector are very common among farm workers, causing many injuries and occupational diseases every year. Agricultural employees are exposed to multiple conditions and various allergenic substances, which could be related to onset of anaphylactic reactions. This systematic review highlights the main clinical manifestation, the allergens that are mostly involved and the main activities that are usually involved. This research includes articles published on the major databases (PubMed, Cochrane Library, Scopus), using a combination of keywords. The online search yielded 489 references; after selection, by the authors, 36 articles (nine reviews and 27 original articles) were analyzed. From this analysis, the main clinical problems that were diagnosed in this category were respiratory (ranging from rhinitis to asthma) and dermatological (eczema, dermatitis, hives) in nature, with a wide symptomatology (from a simple local reaction to anaphylaxis). The main activities associated with these allergic conditions are harvesting or cultivation of fruit and cereals, beekeepers and people working in greenhouses. Finally, in addition to the allergens already known, new ones have emerged, including triticale, wine, spider and biological dust. For these reasons, in the agricultural sector, research needs to be amplified, considering new sectors, new technologies and new products, and ensuring a system of prevention to reduce this risk.

Biomarkers of occupational exposure to pesticides: Systematic review of insecticides

INTRODUCTION

Pesticides are widely used around the world, and rural workers have greater risk of poisoning. The use of biomarkers for insecticides can contribute to the diagnosis and prevention of poisoning.

OBJECTIVE

To identify, in the scientific literature, the biomarkers of occupational exposure to insecticides of different insecticide classes.

METHODS

The PubMed, Lilacs and Embase databases were analyzed using a systematic search strategy and in accordance with the criteria established by the PRISMA methodology. Articles with information related to the use of biomarkers to identify active ingredients, or insecticide metabolites, or effects on the human biological matrices were analyzed.

RESULTS

A total of 840 studies was found, and 30 met the selection criteria. The search identified 118 results for insecticide biomarkers, of which 45% were of exposure, 42% of effect, and 14% of susceptibility. Additionally, 78 were possible biomarkers, and only 67 confirmed to be different biomarkers for insecticides. Acetylcholinesterase (AChE), butyrylcholinesterase (BuChE) and 3,5,6-trichloro-2-pyridinol (TCP-y), specific for Chlorpyrifos, were among the most common biomarkers identified; however, most metabolites found were non-specific.

CONCLUSION

Various insecticide biomarkers were mentioned; nonetheless, only a few are specific and used to identify the wide range of insecticides to which farm workers are exposed.

Acute pesticide poisoning amongst adolescent girls and women in northern Tanzania

BACKGROUND

Acute pesticide poisoning (APP) is reported to affect community health worldwide but its burden in Tanzania is unknown particularly in women. This study examines APP involving adult females and adolescent girls 10 to 19 years in 3 regions of Tanzania which are famous for coffee and vegetable production.

METHODS

Over the period of 12 months, health facility-based surveillance for cases of APP was implemented in 10 Tanzanian healthcare facilities in 2006.

RESULTS

The study identified 108 APP cases of whom 31 (28.7%) occurred amongst adolescent girls. Suicide was the leading poisoning circumstances (60.2%) and the most vulnerable women were 20-29 years old who comprised 38.4% of all cases with suicide as circumstance. Organophosphates (OPs), zinc phosphide, paraquat and endosulfan were common amongst known reported poisoning agents. The annual APP incidence, mortality and Case Fatality Rate for women were 5.1/100,000, 0.2/100,000 and 3.7/100, respectively.

CONCLUSION

APP amongst women in Tanzania is common and this call for diverse preventive interventions to reduce poisoning incidents.

Environmental Health Research in Africa: Important Progress and Promising Opportunities

The World Health Organization in 2016 estimated that over 20% of the global disease burden and deaths were attributed to modifiable environmental factors. However, data clearly characterizing the impact of environmental exposures and health endpoints in African populations is limited. To describe recent progress and identify important research gaps, we reviewed literature on environmental health research in African populations over the last decade, as well as research incorporating both genomic and environmental factors. We queried PubMed for peer-reviewed research articles, reviews, or books examining environmental exposures and health outcomes in human populations in Africa. Searches utilized medical subheading (MeSH) terms for environmental exposure categories listed in the March 2018 US National Report on Human Exposure to Environmental Chemicals, which includes chemicals with worldwide distributions. Our search strategy retrieved 540 relevant publications, with studies evaluating health impacts of ambient air pollution (n=105), indoor air pollution (n = 166), heavy metals (n = 130), pesticides (n = 95), dietary mold (n = 61), indoor mold (n = 9), per- and polyfluoroalkyl substances (PFASs, n = 0), electronic waste (n = 9), environmental phenols (n = 4), flame retardants (n = 8), and phthalates (n = 3), where publications could belong to more than one exposure category. Only 23 publications characterized both environmental and genomic risk factors. Cardiovascular and respiratory health endpoints impacted by air pollution were comparable to observations in other countries. Air pollution exposures unique to Africa and some other resource limited settings were dust and specific occupational exposures. Literature describing harmful health effects of metals, pesticides, and dietary mold represented a context unique to Africa. Studies of exposures to phthalates, PFASs, phenols, and flame retardants were very limited. These results underscore the need for further focus on current and emerging environmental and chemical health risks as well as better integration of genomic and environmental factors in African research studies. Environmental exposures with distinct routes of exposure, unique co-exposures and co-morbidities, combined with the extensive genomic diversity in Africa may lead to the identification of novel mechanisms underlying complex disease and promising potential for translation to global public health.

The Organophosphorus Pesticide Chlorpyrifos Induces Sex-Specific Airway Hyperreactivity in Adult Rats

Occupational and environmental exposures to organophosphorus pesticides (OPs) are associated with increased incidence of asthma and other pulmonary diseases. Although the canonical mechanism of OP neurotoxicity is inhibition of acetylcholinesterase (AChE), it was previously reported that the OP chlorpyrifos (CPF) causes airway hyperreactivity (AHR) in guinea pigs at levels that do not inhibit lung or brain AChE. The guinea pig is considered to have inherently hyperresponsive airways, thus, cross-species validation is needed to confirm relevance to humans. Additionally, sex differences in asthma incidence have been demonstrated in the human population, but whether OP-induced AHR is sex-dependent has not been systematically studied in a preclinical model. In this study, 8-week old male and female Sprague Dawley rats were administered CPF at doses causing comparable AChE inhibition in whole lung homogenate (30 mg/kg in males, 7 mg/kg in females, sc) prior to assessing pulmonary mechanics in response to electrical stimulation of the vagus nerves at 24 h, 48 h, 72 h, 7 d or 14 d post-exposure in males, and 24 h or 7 d post-exposure in females. CPF significantly potentiated vagally induced airway resistance and tissue elastance at 7 d post-exposure in males, and at 24 h and 7 d post-exposure in females. These effects occurred independent of significant AChE inhibition in cerebellum, blood, trachealis, or isolated airway, suggesting that AChE independent OP-induced airway hyperreactivity is a cross-species phenomenon. These findings have significant implications for assessing the risk posed by CPF, and potentially other OPs, to human health and safety.

Relationship between cumulative exposure to pesticides and sleep disorders among greenhouse vegetable farmers

Background

In the northern region of China, many greenhouse vegetable farmers are exposed to high cumulative levels of pesticides due to long-term work in greenhouses that impacts their health. The aim of the current study was to identify the relationship between cumulative pesticide exposure and sleep disorders among farmers in Yinchuan, Northwest China.

Methods

A cross-sectional study was conducted for 3 consecutive years in 2015, 2016 and 2017. Using a random sampling to select the resident teams, 1366 participants were enrolled, and information was collected via face-to-face interviews by trained investigators. Ordinal logistic, multinomial logistic and poisson logistic regression models were used to identify the associations between cumulative exposure intensity (CEI) and sleep disorders.

Results

High CEI (OR = 1.56, 95% CI: 1.02–3.38) was associated with short sleep duration when compared with low CEI in the Full Model. CEI was not associated with long sleep duration. Self-rated sleep quality was associated with medium (OR = 1.46, 95% CI: 1.10–2.00) and high (OR = 2.50, 95% CI: 1.83–3.40) CEI. Similarly, having difficulty sleeping was associated with medium (OR = 1.52, 95% CI: 1.02–2.24) and high (OR = 1.74, 95% CI: 1.16–2.62) CEI. Differences in the associations by gender were also noted.

Conclusion

CEI was associated with sleep disorders, and gender differences were observed. Efforts should be made by local governments to address sleep problems that result from cumulative pesticide exposure in farmers, and gender differences should be considered.

Electronic supplementary material

The online version of this article (10.1186/s12889-019-6712-6) contains supplementary material, which is available to authorized users.

Mechanisms of organophosphorus pesticide toxicity in the context of airway hyperreactivity and asthma

Numerous epidemiologic studies have identified an association between occupational exposures to organophosphorus pesticides (OPs) and asthma or asthmatic symptoms in adults. Emerging epidemiologic data suggest that environmentally relevant levels of OPs may also be linked to respiratory dysfunction in the general population and that in utero and/or early life exposures to environmental OPs may increase risk for childhood asthma. In support of a causal link between OPs and asthma, experimental evidence demonstrates that occupationally and environmentally relevant OP exposures induce bronchospasm and airway hyperreactivity in preclinical models. Mechanistic studies have identified blockade of autoinhibitory M2 muscarinic receptors on parasympathetic nerves that innervate airway smooth muscle as one mechanism by which OPs induce airway hyperreactivity, but significant questions remain regarding the mechanism(s) by which OPs cause neuronal M2 receptor dysfunction and, more generally, how OPs cause persistent asthma, especially after developmental exposures. The goals of this review are to 1) summarize current understanding of OPs in asthma; 2) discuss mechanisms of OP neurotoxicity and immunotoxicity that warrant consideration in the context of OP-induced airway hyperreactivity and asthma, specifically, inflammatory responses, oxidative stress, neural plasticity, and neurogenic inflammation; and 3) identify critical data gaps that need to be addressed in order to better protect adults and children against the harmful respiratory effects of low-level OP exposures.

Exposure to pesticides and the associated human health effects

Pesticides are used widely to control weeds and insect infestation in agricultural fields and various pests and disease carriers (e.g., mosquitoes, ticks, rats, and mice) in houses, offices, malls, and streets. As the modes of action for pesticides are not species-specific, concerns have been raised about environmental risks associated with their exposure through various routes (e.g., residues in food and drinking water). Although such hazards range from short-term (e.g., skin and eye irritation, headaches, dizziness, and nausea) to chronic impacts (e.g., cancer, asthma, and diabetes), their risks are difficult to elucidate due to the involvement of various factors (e.g., period and level of exposure, type of pesticide (regarding toxicity and persistence), and the environmental characteristics of the affected areas). There are no groups in the human population that are completely unexposed to pesticides while most diseases are multi-causal to add considerable complexity to public health assessments. Hence, development of eco-friendly pesticide alternatives (e.g., EcoSMART) and Integrated Pest Management (IPM) techniques is desirable to reduce the impacts of pesticides. This paper was hence organized to present a comprehensive review on pesticides with respect to their types, environmental distribution, routes of exposure, and health impacts.

Pesticides: an update of human exposure and toxicity

Pesticides are a family of compounds which have brought many benefits to mankind in the agricultural, industrial, and health areas, but their toxicities in both humans and animals have always been a concern. Regardless of acute poisonings which are common for some classes of pesticides like organophosphoruses, the association of chronic and sub-lethal exposure to pesticides with a prevalence of some persistent diseases is going to be a phenomenon to which global attention has been attracted. In this review, incidence of various malignant, neurodegenerative, respiratory, reproductive, developmental, and metabolic diseases in relation to different routes of human exposure to pesticides such as occupational, environmental, residential, parental, maternal, and paternal has been systematically criticized in different categories of pesticide toxicities like carcinogenicity, neurotoxicity, pulmonotoxicity, reproductive toxicity, developmental toxicity, and metabolic toxicity. A huge body of evidence exists on the possible role of pesticide exposures in the elevated incidence of human diseases such as cancers, Alzheimer, Parkinson, amyotrophic lateral sclerosis, asthma, bronchitis, infertility, birth defects, attention deficit hyperactivity disorder, autism, diabetes, and obesity. Most of the disorders are induced by insecticides and herbicides most notably organophosphorus, organochlorines, phenoxyacetic acids, and triazine compounds.

Relationship between Pesticide Metabolites, Cytokine Patterns, and Asthma-Related Outcomes in Rural Women Workers

The objective of this study was to investigate the relationship between exposure to organophosphate (OP) and pyrethroid (PYR) pesticides with serum cytokine patterns and asthma-related outcomes among rural women workers. A cross-sectional study was conducted among rural women (n = 211), including those working and living on farms and nearby town dwellers. Pesticide exposure was assessed using urinary metabolite concentrations of OP and PYR pesticides. Health outcome assessment was ascertained through the European Community Respiratory Health Survey (ECRHS) questionnaire, fractional exhaled nitric oxide (FeNO), and serum cytokines associated with asthma. The prevalence of doctor-diagnosed asthma was 11%, adult-onset asthma 9%, and current asthma 6%. In this population, the proportion of T helper type 2 (Th2) cytokines (interleukin (IL)-4, IL-5, and IL-13) detectable in subjects was between 18% and 40%, while the proportion of non-Th2 cytokines (IL-6, IL-8, IL-10, IL-17, and interferon gamma) was between 35% and 71%. Most Th2 and non-Th2 cytokines were positively associated with either OP or PYR metabolites. Non-Th2 cytokines showed much stronger associations with OP metabolites (Dimethyl phosphate OR = 4.23; 95% CI: 1.54-11.65) than Th2 cytokines (Dimethyl phosphate OR = 1.69; 95% CI: 0.83-3.46). This study suggests that exposure to most OP and some PYR pesticides may be associated with asthma-related cytokines, with non-Th2 cytokines demonstrating consistently stronger relationships.

Glufosinate aerogenic exposure induces glutamate and IL-1 receptor dependent lung inflammation

Glufosinate-ammonium (GLA), the active component of an herbicide, is known to cause neurotoxicity. GLA shares structural analogy with glutamate. It is a powerful inhibitor of glutamine synthetase (GS) and may bind to glutamate receptors. Since these potentials targets of GLA are present in lung and immune cells, we asked whether airway exposure to GLA may cause lung inflammation in mice. A single GLA exposure (1 mg/kg) induced seizures and inflammatory cell recruitment in the broncho-alveolar space, and increased myeloperoxidase (MPO), inducible NO synthase (iNOS), interstitial inflammation and disruption of alveolar septae within 6-24 h. Interleukin 1β (IL-1β) was increased and lung inflammation depended on IL-1 receptor 1 (IL-1R1). We demonstrate that glutamate receptor pathway is central, since the N-methyl-D-aspartate (NMDA) receptor inhibitor MK-801 prevented GLA-induced lung inflammation. Chronic exposure (0.2 mg/kg 3× per week for 4 weeks) caused moderate lung inflammation and enhanced airway hyperreactivity with significant increased airway resistance. In conclusion, GLA aerosol exposure causes glutamate signalling and IL-1R-dependent pulmonary inflammation with airway hyperreactivity in mice.

Association between occupational exposures to pesticides with heterogeneous chemical structures and farmer health in China

This study analyzed the associations of farmers’ exposure to organophosphates (OPs), organosulfurs (OSs), organonitrogens (ONs) and pyrethroids (PYRs) with parameters of the blood complete counts (CBC), a blood chemistry panel (BCP) and the conventional nerve conduction studies among 224 farmers in China in 2012. Two health examinations and a series of follow-up field surveys were conducted. Multiple linear regression analyses were used to evaluate the associations. The results show considerable associations between multiple groups of pesticides and several CBC parameters, but it was not enough to provide evidence of hematological disorders. The short- and medium-term OPs exposures were mainly associated with liver damage and peripheral nerve impairment, respectively, while OSs exposure might induce liver damage and renal dysfunction. The neurotoxicity of ONs was second only to OPs in addition to its potential liver damage and the induced alterations in glucose. In comparison, the estimated results show that PYRs would be the least toxic in terms of the low-dose application. In conclusion, occupational exposures to pesticides with heterogeneous chemical structures are associated with farmer health in different patterns, and the association between a specific group of pesticides and farmer health also differs between the short- and medium-term exposures.