Longitudinal investigation of haematological alterations among permethrin-exposed pesticide applicators in the Biomarkers of Exposure and Effect in Agriculture study

Multiple Myeloma and Occupational Risk Factors: A Narrative Review

Multiple Myeloma (MM) is a neoplastic hematologic disorder caused by the excessive proliferation of plasma cells and leads to bone lesions, anemia, and kidney failure. No definite etiology has been proposed for MM, but several environmental and genetic risk factors have been implicated so far. Exposure to pesticides, benzene, and organic solvents like methyl chloride have been considered a potential risk factor. Asbestos, ionizing radiation, and wood dust exposure have also been associated with MM. As MM is a relatively rare condition, the number of studies is insufficient, and in many studies, only a few study participants recall exposure to any agents. Therefore, establishing a definite risk factor is cumbersome and further studies with large study samples are needed. By recognizing these occupational risk factors, clinicians can encourage employees to reduce their exposure as more as possible and implement precautionary measures. In this review, we highlighted the current research on the potential association between occupational exposures and MM. Because of these studies, new regulations with the goal of occupational exposure reduction are anticipated in the future.

Glyphosate Use and Mosaic Loss of Chromosome Y among Male Farmers in the Agricultural Health Study

BACKGROUND

Glyphosate is the most commonly used herbicide worldwide and has been implicated in the development of certain hematologic cancers. Although mechanistic studies in human cells and animals support the genotoxic effects of glyphosate, evidence in human populations is scarce.

OBJECTIVES

We evaluated the association between lifetime occupational glyphosate use and mosaic loss of chromosome Y (mLOY) as a marker of genotoxicity among male farmers.

METHODS

We analyzed blood-derived DNA from 1,606 farmers ≥ 50 years of age in the Biomarkers of Exposure and Effect in Agriculture study, a subcohort of the Agricultural Health Study. mLOY was detected using genotyping array intensity data in the pseudoautosomal region of the sex chromosomes. Cumulative lifetime glyphosate use was assessed using self-reported pesticide exposure histories. Using multivariable logistic regression, we estimated odds ratios (ORs) and 95% confidence intervals (CIs) for the associations between glyphosate use and any detectable mLOY (overall mLOY) or mLOY affecting ≥ 10 % of cells (expanded mLOY).

RESULTS

Overall, mLOY was detected in 21.4% of farmers, and 9.8% of all farmers had expanded mLOY. Increasing total lifetime days of glyphosate use was associated with expanded mLOY [highest vs. lowest quartile; OR = 1.75 (95% CI: 1.00, 3.07), p trend = 0.03 ] but not with overall mLOY; the associations with expanded mLOY were most apparent among older (≥ 70 years of age) men [OR = 2.30 (95% CI: 1.13, 4.67), p trend = 0.01 ], never smokers [OR = 2.32 (95% CI: 1.04, 5.21), p trend = 0.04 ], and nonobese men [OR = 2.04 (95% CI: 0.99, 4.19), p trend = 0.03 ]. Similar patterns of associations were observed for intensity-weighted lifetime days of glyphosate use.

DISCUSSION

High lifetime glyphosate use could be associated with mLOY affecting a larger fraction of cells, suggesting glyphosate could confer genotoxic or selective effects relevant for clonal expansion. As the first study to investigate this association, our findings contribute novel evidence regarding the carcinogenic potential of glyphosate and require replication in future studies. https://doi.org/10.1289/EHP12834.

Assessing the impact of coexposure on the measurement of biomarkers of exposure to the pyrethroid lambda-cyhalothrin in agricultural workers

There are few published data on the impact of combined exposure to multiple pesticides (coexposure) on levels of biomarkers of exposure in workers, which may alter their toxicokinetics and thus the interpretation of biomonitoring data. This study aimed to assess the impact of coexposure to two pesticides with shared metabolism pathways on levels of biomarkers of exposure to pyrethroid pesticides in agricultural workers. The pyrethroid lambda-cyhalothrin (LCT) and the fungicide captan were used as sentinel pesticides, since they are widely sprayed concomitantly in agricultural crops. Eighty-seven (87) workers assigned to different tasks (application, weeding, picking) were recruited. The recruited workers provided two-consecutive 24-h urine collections following an episode of lambda-cyhalothrin application alone or in combination with captan or following tasks in the treated fields, as well as a control collection. Concentrations of lambda-cyhalothrin metabolites - 3-(2-chloro-3,3,3-trifluoroprop-1-en-1-yl)-2,2-dimethyl-cyclopropanecarboxylic acid (CFMP) and 3-phenoxybenzoic acid (3-PBA) - were measured in the samples. Potential determinants of exposure established in a previous study, including the task performed and personal factors were documented by questionnaire. Multivariate analyses showed that coexposure did not have a statistically significant effect on the observed urinary levels of 3-PBA (Exp(β) (95% confidence interval (95% CI)): 0.94 (0.78-1.13)) and CFMP (1.10 (0.93-1.30). The repeated biological measurements ("time variable") - defined as the within-subjects variable - was a significant predictor of observed biological levels of 3-PBA and CFMP; the within-subjects variance (Exp(β) (95% (95% CI)) for 3-PBA and CFMP was 1.11 (1.09-3.49) and 1.25 (1.20-1.31). Only the main occupational task was associated with urinary levels of 3-PBA and CFMP. Compared to the weeding or picking task, the pesticide application task was associated with higher urinary 3-PBA and CFMP concentrations. In sum, coexposure to agricultural pesticides in the strawberry fields did not increase pyrethroid biomarker concentrations at the exposure levels observed in the studied workers. The study also confirmed previous data suggesting that applicators were more exposed than workers assigned to field tasks such as weeding and picking.

Monitoring residues of pesticides in food in Brazil: A multiscale analysis of the main contaminants, dietary cancer risk estimative and mechanisms associated

Introduction

Pesticides pose a risk for cancer development and progression. People are continuously exposed to such substances by several routes, including daily intake of contaminated food and water, especially in countries that are highly pesticide consumers and have very permissive legislation about pesticide contamination as Brazil. This work investigated the relationship among pesticides, food contamination, and dietary cancer risk.

Methods

Analyzed two social reports from the Brazilian Government: the Program for Analysis of Residues of Pesticides in Food (PARA) and The National Program for Control of Waste and Contaminants (PNCRC).

Results and discussion

First, we characterized the main pesticide residues detected over the maximum limits allowed by legislation or those prohibited for use in food samples analyzed across the country. Based on this list, we estimated the dietary cancer risks for some of the selected pesticides. Finally, we searched for data about dietary cancer risks and carcinogenic mechanisms of each pesticide. We also provided a critical analysis concerning the pesticide scenario in Brazil, aiming to discuss the food contamination levels observed from a geographical, political, and public health perspective. Exposures to pesticides in Brazil violate a range of human rights when food and water for human consumption are contaminated.

Urinary 3-phenoxybenzoic acid (3-PBA) levels and changes in hematological parameters in Korean adult population: A Korean National Environmental Health Survey (KoNEHS) 2012-2014 analysis

Pyrethroid insecticides have been broadly used as pest control in agriculture and residential spaces, exerting high effectiveness of insecticidal property and relatively low toxicity to humans. Several animal studies suggested that exposure to pyrethroids may induce hematological abnormalities, thereby altering the number of blood cells and resulting in blood disorders. However, no epidemiologic study has reported on the effect of pyrethroid insecticide exposure on hematological changes, except for occupational exposure. This study aimed to investigate the effect of urinary 3-phenoxybenzoic acid (3-PBA) concentrations on hematological parameters in a representative South Korean adult population. We analyzed data from 6296 adults enrolled in the Korean National Environmental Health Survey (2012-2014). We employed multiple linear regression analysis to evaluate the association of urinary 3-PBA levels with eight hematological profiles: white blood cells (WBCs), red blood cells (RBCs), hemoglobin, hematocrit, platelets, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC). The urinary 3-PBA levels were negatively associated with WBC, RBC, and hemoglobin levels and positively associated with MCV levels. The direction and magnitude of the association between the 3-PBA and hematological parameters varied according to sex and age. The adverse effects of 3-PBA on hematological parameters were distinctive among males aged 60 years and older. In this age group, 3-PBA levels were negatively associated with the WBC, RBC, hemoglobin, hematocrit, and MCHC levels among males. This study is the first to verify that urinary 3-PBA concentrations at the levels found in a Korean population are associated with blood parameters. This finding merits further investigation to understand the impact of 3-PBA on human blood function and public health.

Investigation of Relationships Between the Geospatial Distribution of Cancer Incidence and Estimated Pesticide Use in the U.S. West

The objective of the study was to evaluate the potential geospatial relationship between agricultural pesticide use and two cancer metrics (pediatric cancer incidence and total cancer incidence) across each of the 11 contiguous states in the Western United States at state and county resolution. The pesticide usage data were collected from the U.S. Geological Survey Pesticide National Synthesis Project database, while cancer data for each state were compiled from the National Cancer Institute State Cancer Profiles. At the state spatial scale, this study identified a significant positive association between the total mass of fumigants and pediatric cancer incidence, and also between the mass of one fumigant in particular, metam, and total cancer incidence (P-value < 0.05). At the county scale, the relationship of all cancer incidence to pesticide usage was evaluated using a multilevel model including pesticide mass and pesticide mass tertiles. Low pediatric cancer rates in many counties precluded this type of evaluation in association with pesticide usage. At the county scale, the multilevel model using fumigant mass, fumigant mass tertiles, county, and state predicted the total cancer incidence (R-squared = 0.95, NSE = 0.91, and Sum of square of residuals [SSR] = 8.22). Moreover, this study identified significant associations between total fumigant mass, high and medium tertiles of fumigant mass, total pesticide mass, and high tertiles of pesticide mass relative to total cancer incidence across counties. Fumigant application rate was shown to be important relative to the incidence of total cancer and pediatric cancer, at both state and county scales.

Elements to increase translation in pyrethroid epidemiology research: A review

Pyrethroid insecticides have been the subject of numerous epidemiology studies in the past two decades. We examined the pyrethroids epidemiology literature published between 2016 and 2021. Our objective with this exercise was to inform interested readers regarding information on methodological elements that strengthen a study's use for translation (i.e., use in risk assessment) and to describe aspects of future research methods that could improve utility for decision-making. We focused on the following elements: (i) study design that provided evidence that pyrethroid exposure preceded the outcome, (ii) evidence that the method used for exposure characterization was reliable and sufficiently accurate for the intended purpose, and (iii) use of a robust approach for outcome ascertainment. For each of the 74 studies identified via the literature search, we categorized the methodological elements as Acceptable or Supplemental. A study with three Acceptable elements was considered Relevant for risk assessment purposes. Based on our evaluative approach, 18 (24%) of the 74 publications were considered to be Relevant. These publications were categorized as Acceptable for all three elements assessed: confirmed exposure (N = 24), confirmed outcome (N = 64), exposure preceded the outcome (N = 44). Three of these studies were birth cohorts. There were 15 Relevant publications of adults which included 10 Agricultural Health Study cohort publications of self-reported permethrin. Overall, the majority of the reviewed studies used methods that did not permit a determination that pyrethroid exposure preceded the outcome, and/or did not utilize robust methods for exposure assessment and outcome ascertainment. There is an opportunity for investigators and research sponsors to build on the studies reviewed here and to incorporate more translational approaches to studying exposure/outcome associations related to pesticides and other chemicals.

Cancer and occupational exposure to pesticides: a bibliometric study of the past 10 years

Occupational exposure to pesticides has been identified as a major trigger of the development of cancer. Pesticides can cause intoxication in the individuals who manipulate them through either inhalation, ingestion, or dermal contact. Given this, we investigated the association between the incidence of cancer and occupational exposure to pesticides through a bibliometric analysis of the studies published between 2011 and 2020, based on 62 papers selected from the Scopus database. The results indicated an exponential increase in the number of studies published over the past decade, with most of the research being conducted in the USA, France, India, and Brazil, although a further 17 nations were also involved in the research on the association between cancer and pesticides. The principal classes of pesticides investigated in relation to their role in intoxication and cancer were insecticides, herbicides, and fungicides. The types of cancer reported most frequently were multiple myeloma, bladder cancer, non-Hodgkin's lymphoma, prostate cancer, leukemia, and breast cancer. Despite the known association between pesticides and cancer, studies are still relatively scarce in comparison with the global scale of the use of these xenobiotic substances, which is related to the increasing demand for agricultural products throughout the world.

Exposure to Sub-Lethal Doses of Permethrin Is Associated with Neurotoxicity: Changes in Bioenergetics, Redox Markers, Neuroinflammation and Morphology

Permethrin (PERM) is a member of the class I family of synthetic pyrethroids. Human use has shown that it affects different systems, with wide health dysfunctions. Our aim was to determine bioenergetics, neuroinflammation and morphology changes, as redox markers after subacute exposure to PERM in rats. We used MDA determination, protein carbonyl assay, mitochondrial O₂ consumption, expression of pro-inflammatory cytokines and a deep histopathological analysis of the hippocampus. PERM (150 mg/kg and 300 mg/kg body weight/day, o.v.) increased lipoperoxidation and carbonylated proteins in a dose-dependent manner in the brain regions. The activities of antioxidant enzymes glutathione peroxidase, reductase, S-transferase, catalase, and superoxide dismutase showed an increase in all the different brain areas, with dose-dependent effects in the cerebellum. Cytokine profiles (IL-1β, IL-6 and TNF-α) increased in a dose-dependent manner in different brain tissues. Exposure to 150 mg/kg of permethrin induced degenerated and/or dead neurons in the rat hippocampus and induced mitochondrial uncoupling and reduction of oxidative phosphorylation and significantly decreased the respiratory parameters state 3-associated respiration in complex I and II. PERM exposure at low doses induces reactive oxygen species production and imbalance in the enzymatic antioxidant system, increases gene expression of pro-inflammatory interleukins, and could lead to cell damage mediated by mitochondrial functional impairment.

Association between Haematological Parameters and Exposure to a Mixture of Organophosphate and Neonicotinoid Insecticides among Male Farmworkers in Northern Thailand

Exposure to insecticides may result in various health problems. This study investigated the association between haematological parameters and exposure to a mixture of organophosphate (OP) and neonicotinoid (NEO) insecticides among male farmworkers in Fang district, Chiang Mai province, northern Thailand. Concentrations of urinary dialkylphosphates, non-specific metabolites of OPs, and NEOs and their metabolites and haematological parameters were measured in 143 male farmworkers. The Bayesian kernel machine regression model was employed to evaluate the associations. Exposure to a mixture of insecticides was significantly associated with the mean corpuscular haemoglobin concentration (MCHC) when the concentrations of all the compounds and their metabolites were at the 60th percentile or higher compared with the 50th percentile. Furthermore, exposure to clothianidin (CLO) showed a decreasing association with MCHC when all the other insecticides were at their mean concentrations. CLO was the most likely compound to reduce MCHC, and this was confirmed by sensitivity analysis. These findings suggest that exposure to NEO insecticides, especially CLO, affects the haematological status relating to haemoglobin parameters.

Lifetime Pesticide Use and Monoclonal Gammopathy of Undetermined Significance in a Prospective Cohort of Male Farmers

BACKGROUND

Farmers have a higher incidence of multiple myeloma, and there is suggestive evidence of an elevated prevalence of its precursor, monoclonal gammopathy of undetermined significance (MGUS), relative to the general population. Pesticide exposures are suspected to play a role; however, the biologic plausibility for associations with multiple myeloma remains unclear.

OBJECTIVES

Our objectives were to examine the prevalence of MGUS and evaluate associations with a wide range of pesticides in a large sample of farmers.

METHODS

We obtained sera and assessed MGUS among 1,638 male farmers ≥ 50  years of age in the Agricultural Health Study (AHS), a prospective cohort in Iowa and North Carolina. Odds ratios (ORs) and 95% confidence intervals (CIs) were computed to estimate associations with MGUS for recent use (within the 12 months before phlebotomy) and cumulative intensity-weighted lifetime days of use of specific pesticides.

RESULTS

The age-standardized MGUS prevalence was significantly elevated among AHS farmers (7.7%) compared with demographically similar men in the National Health and Nutrition Examination Survey (2.8%) or Olmsted County, Minnesota (3.8%; p < 0.001 ). Recent use of permethrin was associated with MGUS [recent use vs. no recent use, OR = 1.82 (95% CI: 1.06, 3.13)], especially among those who had also used it in the past [recent and past use vs. never use, OR = 2.49 (95% CI: 1.32, 4.69)]. High intensity-weighted lifetime use of the organochlorine insecticides aldrin and dieldrin was associated with MGUS relative to those who never used either of these pesticides [OR = 2.42 (95% CI: 1.29, 4.54); p trend = 0.006 ]. We also observed a positive association with high lifetime use of petroleum oil/distillates as an herbicide, as well as an inverse association with fonofos use.

DISCUSSION

This is the largest investigation of MGUS in farmers and the first to identify an association with MGUS for permethrin, a pyrethroid insecticide previously associated with multiple myeloma. Given the continued widespread use of permethrin in various residential and commercial settings, our findings may have important implications for exposed individuals in the general population. https://doi.org/10.1289/EHP6960.

Autonomic nervous system control of multiple myeloma

The autonomic nervous system (ANS), which consists of antagonistic sympathetic (adrenergic) and parasympathetic (cholinergic) arms, has emerged as an important regulator of neoplastic development, yet little is known about its role in multiple myeloma (MM). Clinical findings that anti-adrenergic β-blocker intake reduces risk of disease-specific death and overall mortality in patients with MM have indicated that adrenergic input may worsen myeloma outcome. However, preclinical studies using β-adrenergic receptor agonists or antagonists produced controversial results as to whether sympathetic pathways promote or inhibit myeloma. Retrospective outcome data demonstrating that high message levels of cholinergic receptor genes predict inferior survival in the Multiple Myeloma Research Foundation CoMMpass trial suggest that parasympathetic input may drive myeloma progression in a subset of patients. Here we review the ill-defined role of the ANS in MM, put myeloma in the context of other cancers, and discuss knowledge gaps that may afford exciting research opportunities going forward.