A task-based assessment of parental occupational exposure to pesticides and childhood acute lymphoblastic leukemia

Agricultural intensification and childhood cancer in Brazil

Over the last several decades, Brazil has become both the world's leading soy producer and the world's leading consumer of hazardous pesticides. Despite identified links between pesticide exposure and carcinogenesis, there has been little population-level research on the effects of pesticide intensification on broader human health in Brazil. We estimate the relationship between expanded soy production-and related community exposure to pesticides-on childhood cancer incidence using 15 y of data on disease mortality. We find a statistically significant increase in pediatric leukemia following expanded local soy production, but timely access to treatment mitigates this relationship. We show that pesticide exposure likely occurs via water supply penetration. Our findings represent only the tip of the iceberg for substantial health externalities of high-input crop production and land use change. Our results are of particular interest in developing contexts with demand for intensified food production systems and underscore the need for stronger regulation of pesticides and increased public health attention to exposure in the broader community.

Occupational exposure to pesticides and endometrial cancer in the Screenwide case-control study

BACKGROUND

Endometrial cancer is the most common gynaecological tumour in developed countries and disease burden is expected to increase over the years. Identifying modifiable risk factors may help developing strategies to reduce the expected increasing incidence of these neoplasms.

OBJECTIVE

This study evaluates the association between occupational exposure to pesticides and endometrial cancer using data from a recent case-control study in Spain.

METHODS

The analyses included data from 174 consecutive incident endometrial cancer cases and 216 hospital controls frequency-matched by age. Data were collected through structured epidemiological questionnaires and exposure to pesticides was assessed using a Spanish job-exposure matrix (MatEmESp).

RESULTS

Overall, 12% of controls and 18% of cases were occupationally exposed to pesticides. We observed a positive association between occupational exposure to pesticides and endometrial cancer (OR = 2.08; 95% CI = 1.13-3.88 compared to non-exposed). In general, exposures that occurred farther in the past were significantly associated with endometrial cancer. Exposure to insecticides, fungicides and herbicides were positively associated with endometrial cancer (OR = 2.08; 95% CI = 1.13-3.88, OR = 4.40; 95% CI = 1.65-13.33, and OR = 5.25; 95% CI = 1.84-17.67, respectively). The agricultural, poultry and livestock activities scenario was associated with endometrial cancer (OR = 4.16; 95% CI = 1.59-12.32), while the cleaning exposure scenario was not (OR = 1.22; 95% CI = 0.55-2.67).

CONCLUSIONS

Assessment of occupational exposure to pesticides assessed using a Spanish job-exposure matrix revealed a positive association with endometrial cancer. The elucidation of the role of pesticide compounds on endometrial cancer should shed a light on the aetiology of this tumour.

Research on knowledge construction and analysis of pesticide exposure to children based on bibliometrics

Pesticide exposure is a major health problem that cannot be ignored, and children are particularly vulnerable and sensitive. As a result, the study of health damage in children caused by pesticide exposure has gradually developed into an important cross-disciplinary research topic. In this study, we reviewed the current state, characteristics, and trends of existing research findings and summarized them comprehensively and systematically through bibliometrics. We collected and examined a large number of studies using Citespace and Vosviewer, employing a clustering method to analyze the effects of pesticide exposure on children and to highlight the hot keywords in the research field. Through an analysis of the active time of high-frequency keywords, we found that the research field is in a hot spot, and the occurrence value of keywords was used to judge the innovation of the research results, thereby highlighting the frontier and key directions of future research in this field. We conclude that in addition to core pesticides, children, exposure, and other malaria and polychlorinated biphenyls also appear as high-frequency keywords in the research field of pesticide exposure effects on children. The core issues of concern in this field include occupational pesticide exposure and childhood leukemia, history of pesticide exposure during pregnancy and childhood leukemia, environmental factors and dietary intake and organophosphorus pesticide exposure in children, and pyrethroid pesticide exposure and neurobehavioral development in children. Future research may focus on how to control the safe use of pesticides, quantitative research on pesticide hazards, and potential effects on children's health.

Incidence and Mortality Rates for Childhood Acute Lymphoblastic Leukemia in Puerto Rican Hispanics, 2012-2016

BACKGROUND

Acute lymphoblastic leukemia (ALL) accounts for 80% of all leukemias diagnosed in children. Although ALL age patterns are consistent across racial/ethnic groups, their incidence and mortality rates are highly variable. We assessed the age-standardized ALL incidence and mortality rates of Puerto Rican Hispanic (PRH) children and compared them with those of US mainland Hispanics (USH), non-Hispanic Whites (NHW), non-Hispanic Blacks (NHB), and Non-Hispanic Asian or Pacific Islanders (NHAPI).

METHODS

Differences between racial/ethnic groups were assessed by estimating the standardized rate ratio (SRR) for 2010 to 2014. Secondary data analyses of the Puerto Rico Central Cancer Registry and the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) databases were performed for the 2001 to 2016 period.

RESULTS

PRH children had 31% lower incidence rates than USH, but 86% higher incidence rates than NHB. In addition, the incidence trends of ALL increased significantly from 2001 to 2016 among PRH and USH, with 5% and 0.9% per year, respectively. Moreover, PRH have a lower 5-year overall survival (81.7%) when compared with other racial/ethnic groups.

CONCLUSIONS

PRH children were found to have disparities in ALL incidence and mortality rates compared with other racial/ethnic groups in the US. Additional research is warranted to identify the genetic and environmental risk factors that may be associated with the disparities observed.

IMPACT

This is the first study reporting the incidence and mortality rates of childhood ALL for PRH and making comparisons with other racial/ethnic groups in the US. See related commentary by Mejía-Aranguré and Núñez-Enríquez, p. 999.

Environmentally Induced Sperm RNAs Transmit Cancer Susceptibility to Offspring in a Mouse Model

DNA sequence accounts for the majority of disease heritability, including cancer. Yet, not all familial cancer cases can be explained by genetic factors. It is becoming clear that environmentally induced epigenetic inheritance occurs and that the progeny's traits can be shaped by parental environmental experiences. In humans, epidemiological studies have implicated environmental toxicants, such as the pesticide DDT, in intergenerational cancer development, including breast and childhood tumors. Here, we show that the female progeny of males exposed to DDT in the pre-conception period have higher susceptibility to developing aggressive tumors in mouse models of breast cancer. Sperm of DDT-exposed males exhibited distinct patterns of small non-coding RNAs, with an increase in miRNAs and a specific surge in miRNA-10b levels. Remarkably, embryonic injection of the entire sperm RNA load of DDT-exposed males, or synthetic miRNA-10b, recapitulated the tumor phenotypes observed in DDT offspring. Mechanistically, miR-10b injection altered the transcriptional profile in early embryos with enrichment of genes associated with cell differentiation, tissue and immune system development. In adult DDT-derived progeny, transcriptional and protein analysis of mammary tumors revealed alterations in stromal and in immune system compartments. Our findings reveal a causal role for sperm RNAs in environmentally induced inheritance of cancer predisposition and, if confirmed in humans, this could help partially explain some of the "missing heritability" of breast, and other, malignancies.

The Pediatrician's Role in Protecting Children from Environmental Hazards

Children suffer disproportionately from disease and disability due to environmental hazards, for reasons rooted in their biology. The contribution is substantial and increasingly recognized, particularly due to ever-increasing awareness of endocrine disruption. Regulatory actions can be traced directly to reductions in toxic exposures, with tangible benefits to society. Deep flaws remain in the policy framework in industrialized countries, failing to offer sufficient protection, but are even more limited in industrializing nations where the majority of chemical production and use will occur by 2030. Evidence-based steps for reducing chemical exposures associated with adverse health outcomes exist and should be incorporated into anticipatory guidance.

Parental occupational exposure to combustion products, metals, silica and asbestos and risk of childhood leukaemia: Findings from the Childhood Cancer and Leukaemia International Consortium (CLIC)

Parental occupational exposures around conception (father) or during pregnancy (mother) have been hypothesized as potential predisposing factors for childhood leukaemia. We investigated parental exposure to several known occupational carcinogens and childhood leukaemia risk. We conducted a pooled analysis using case-control data from four European countries (3362 childhood leukemia cases and 6268 controls). Parental occupational exposures to polycyclic aromatic hydrocarbons (PAH), diesel engine exhaust (DEE), chromium, nickel, crystalline silica, and asbestos were assessed by a general population job-exposure matrix. We estimated odd ratios (ORs) and 95% confidence intervals (CIs) using unconditional logistic regression models for all childhood leukaemia combined, by leukaemia type (ALL and AML) and by ALL subtype (B-lineage and T-lineage). We found an association between high paternal occupational exposure to crystalline silica and childhood ALL (OR 2.20, CI 1.60-3.01) with increasing trend from no exposure to high exposure (P = <0.001), and also for AML (OR 2.03, CI 1.04-3.97; P for trend = 0.008). ORs were similar for B- and T-lineage ALL. For ALL, ORs were also slightly elevated with wide confidence intervals for high paternal occupational exposure to chromium (OR 1.23, CI 0.77-1.96), and DEE (OR 1.21, CI 0.82-1.77). No associations were observed for paternal exposures to nickel, PAH and asbestos. For maternal occupational exposure we found several slightly elevated odds ratios but mostly with very wide confidence intervals due to low numbers of exposed mothers. This is a first study suggesting an association between fathers' occupational exposure to crystalline silica and an increased risk of childhood leukaemia in their offspring. As this association was driven by certain occupations (field crop farmers and miners) where other potentially relevant exposures like pesticides and radon may also occur, more research is needed to confirm our findings of an association with crystalline silica, and if so, mechanistic studies to understand the pathways.

Unconventional Oil and Gas Development Exposure and Risk of Childhood Acute Lymphoblastic Leukemia: A Case-Control Study in Pennsylvania, 2009-2017

BACKGROUND

Unconventional oil and gas development (UOGD) releases chemicals that have been linked to cancer and childhood leukemia. Studies of UOGD exposure and childhood leukemia are extremely limited.

OBJECTIVE

The objective of this study was to evaluate potential associations between residential proximity to UOGD and risk of acute lymphoblastic leukemia (ALL), the most common form of childhood leukemia, in a large regional sample using UOGD-specific metrics, including a novel metric to represent the water pathway.

METHODS

We conducted a registry-based case-control study of 405 children ages 2-7 y diagnosed with ALL in Pennsylvania between 2009-2017, and 2,080 controls matched on birth year. We used logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between residential proximity to UOGD (including a new water pathway-specific proximity metric) and ALL in two exposure windows: a primary window (3 months preconception to 1 y prior to diagnosis/reference date) and a perinatal window (preconception to birth).

RESULTS

Children with at least one UOG well within 2 km of their birth residence during the primary window had 1.98 times the odds of developing ALL in comparison with those with no UOG wells [95% confidence interval (CI): 1.06, 3.69]. Children with at least one vs. no UOG wells within 2 km during the perinatal window had 2.80 times the odds of developing ALL (95% CI: 1.11, 7.05). These relationships were slightly attenuated after adjusting for maternal race and socio-economic status [odds ratio (OR) = 1.74 (95% CI: 0.93, 3.27) and OR = 2.35 (95% CI: 0.93, 5.95)], respectively). The ORs produced by models using the water pathway-specific metric were similar in magnitude to the aggregate metric.

DISCUSSION

Our study including a novel UOGD metric found UOGD to be a risk factor for childhood ALL. This work adds to mounting evidence of UOGD's impacts on children's health, providing additional support for limiting UOGD near residences. https://doi.org/10.1289/EHP11092.

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.

Assessment of Pediatric Cancer and Its Relationship to Environmental Contaminants: An Ecological Study in Idaho

The primary aim of this study was to determine the degree to which a multivariable principal component model based on several potentially carcinogenic metals and pesticides could explain the county-level pediatric cancer rates across Idaho. We contend that human exposure to environmental contaminants is one of the reasons for increased pediatric cancer incidence in the United States. Although several studies have been conducted to determine the relationship between environmental contaminants and carcinogenesis among children, research gaps exist in developing a meaningful association between them. For this study, pediatric cancer data was provided by the Cancer Data Registry of Idaho, concentrations of metals and metalloids in groundwater were collected from the Idaho Department of Water Resources, and pesticide use data were collected from the United States Geological Survey. Most environmental variables were significantly intercorrelated at an adjusted P-value <0.01 (97 out of 153 comparisons). Hence, a principal component analysis was employed to summarize those variables to a smaller number of components. An environmental burden index (EBI) was constructed using these principal components, which categorized the environmental burden profiles of counties into low, medium, and high. EBI was significantly associated with pediatric cancer incidence (P-value <0.05). The rate ratio of high EBI profile to low EBI profile for pediatric cancer incidence was estimated as 1.196, with lower and upper confidence intervals of 1.061 and 1.348, respectively. A model was also developed in the study using EBI to estimate the county-level pediatric cancer incidence in Idaho (Nash-Sutcliffe Efficiency = 0.97).

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.

Application of Postcolonial Feminist Theory, Chicana Feminist Thought, and Black Feminist Thought in Analyzing the Mental Health Needs of Latina Migrant Farmworkers: A Shared Legacy

The purpose of this theoretical article is to analyze the utility of postcolonial, Black, and Chicana feminist frameworks to inform nursing research and practice specific to mental health needs of Latina women migrant farmworkers. Twentieth-century Western feminist narratives overlooked the intersecting systems of oppression experienced by women of color, including Latina women. Feminist epistemologies are useful in understanding the complex sociopolitical contexts that have impacted women's health outcomes and well-being. This analysis is critical to shaping nursing care that meets the unique health needs of migrant farmworker women while considering their sociopolitical realities.

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.

Global, regional, and national cancer incidence and death for 29 cancer groups in 2019 and trends analysis of the global cancer burden, 1990-2019

Background and aims

Cancer will soon become the leading cause of death in every country in the twenty-first century. This study aimed to analyze the mortality and morbidity of 29 types of cancer in 204 countries or regions from 1990 to 2019 to guide global cancer prevention and control.

Methods

Detailed information for 29 cancer groups was collected from the Global Burden of Disease Study in 2019. The age-standardized incidence rate (ASIR) and age-standardized death rate (ASDR) of the 29 cancer groups were calculated based on sex, age, region, and country. In addition, separate analyses were performed for major cancer types.

Results

In 2019, more than 10 million people died from cancer, which was approximately twice the number in 1990. Tracheal, bronchus, and lung (TBL) cancers collectively showed the highest death rate, and the ASDR of pancreatic cancer increased by 24%, which was cancer with the highest case fatality rate (CFR). The global cancer ASIR showed an increasing trend, with testicular cancer, thyroid cancer, and malignant skin melanoma showing a significant increase. The ASDR and ASIR of cancer in males were about 1.5 times higher than that in females. Individuals over 50 years had the highest risk of developing cancer, with incidences and deaths in this age group accounting for more than 85% of cancers in all age groups. Asia has the heaviest cancer burden due to its high population density, with esophageal cancer in this region accounting for 53% of the total fatalities related to this type of cancer in the world. In addition, the mortality and morbidity of most cancers increased with the increase in the development or socio-demographic index (SDI) in the SDI regions based on the World Bank's Human Development Index (HDI), with cancer characteristics varying in the different countries globally.

Conclusions

The global cancer burden continues to increase, with substantial mortality and morbidity differences among the different regions, ages, countries, gender, and cancer types. Effective and locally tailored cancer prevention and control measures are essential in reducing the global cancer burden in the future.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13045-021-01213-z.

Residential exposure to carbamate, organophosphate, and pyrethroid insecticides in house dust and risk of childhood acute lymphoblastic leukemia

BACKGROUND

Self-reported residential use of pesticides has consistently been associated with increased risk of childhood leukemia. However, these studies were limited in their ability to identify specific insecticide active ingredients that were associated with risk.

OBJECTIVE

We used household carpet dust measurements of 20 insecticides (two carbamate, 10 organophosphate, two organochlorine, and six pyrethroid) as indicators of exposure and evaluated associations with the risk of childhood acute lymphoblastic leukemia (ALL).

METHODS

We conducted a population-based case-control study of 252 ALL cases diagnosed from 1999 to 2007 and 306 birth certificate controls from 35 counties in Central and Northern California. Carpet dust was collected at a second interview (2001-2007) for cases who had not moved since diagnosis (comparable reference date for controls) using a specialized vacuum cleaner in the room where the child spent most of their time or from the household vacuum. Insecticides were categorized as detected (yes/no), or as tertiles or quartiles of their distributions among controls. We calculated odds ratios (OR) and 95% confidence intervals (CI) using unconditional logistic regression adjusting for demographic characteristics, interview year, and season of dust collection.

RESULTS

Permethrin, chlorpyrifos, diazinon, and carbaryl were the most frequently detected insecticide active ingredients. When we compared the highest quartile to the lowest or to non-detections, there was no association with ALL for permethrin (OR Q4 vs. Q1 = 0.81; 95% CI 0.50-1.31), carbaryl (OR Q4 vs. non-detects = 0.61, 95% CI 0.34-1.08) or chlorpyrifos (OR Q4 vs. Q1 = 0.60; 95% CI 0.36-1.00). The highest quartile of diazinon concentration was inversely associated with risk in the single pesticide model but without a monotonic exposure-response (p-trend = 0.14). After adjusting for other common insecticides, the OR was not significant (OR Q4 vs. Q1 = 0.58; 95% CI 0.33-1.05). None of the other insecticides were associated with risk.

CONCLUSION

Our results should be interpreted within the limitations of the case-control study design including the use of a single post-diagnosis dust sample and restriction to residentially stable participants, which may have resulted in selection bias. Although difficult to implement, additional studies with assessment of exposure to insecticide active and non-active ingredients are necessary to elucidate the role of these common exposures in childhood leukemia risk.

Chromosomal abnormalities and dysregulated DNA repair gene expression in farmers exposed to pesticides

Exposure to pesticides is considered a major factor underlying increased risk of hematological disorders in agricultural workers due to its carcinogenic potential. However, genotoxic impact of pesticides in DNA integrity of bone marrow stem cells (BMSC) of farmers exposed is not yet well known. We evaluated presence of chromosomal abnormalities (CA) and mRNA expression of DNA repair targets (ATM, BRCA1, BRCA2, RAD51, XRCC5, XRCC6, LIG4, CSA, CSB, XPA, XPC, XPG) in 90 bone marrow samples of farmers divided into three groups: commercial farming (CF), family farming (FF) and organic farming (OF). Our results showed that farmers in CF (72.7 %) and FF (27.3 %) groups had significantly higher values of CA when compared to OF group (0.0 %; p = 0.003). CF showed lower XPG (p = 0.008), CSA (p < 0.001), ATM (p = 0.036) and LIG4 (p = 0.004) mRNA expression than OF. FF presented lower XPG (p = 0.012) and LIG4 (p = 0.004) expression than OF. CF + FF individual with ≥12 years of exposure to pesticides showed decreased mRNA expression of XPC (p = 0.001), XPG (p = 0.010), CSB (p = 0.05), ATM (p = 0.030) and LIG4 (p = 0.044) than those who have been exposed for <12 years. CF + FF with CA showed a lower expression of BRCA2 when compared to CF + FF group without CA (p = 0.007). These results highlight that genotoxic exposure to pesticides negatively affects expression profile of important DNA repair genes in BMSC, favoring irreparable chromosomal lesions.

How does soil pollution risk perception affect farmers' pro-environmental behavior? The role of income level

Soil pollution is a serious environmental issue in China. As a key subject of agricultural practices, promoting Chinese farmers' Pro-Environmental Behavior (PEB) through increasing their soil pollution risk perception is an important means for soil protection, agricultural transformation and ecological development. In this study, we distinguish four dimensions of soil pollution risk perception: fact perception (FP), loss perception (LP), cause perception (CP) and response behavior ability perception (RBAP). We conceptualize a model that depicts the relationships between the four dimensions of Chinese farmers' soil pollution risk perception and their PEB and the moderating effect of farms' household income level on these relationships. Using a questionnaire survey to collect empirical data, we find: first, the four dimensions of Chinese farmers' soil pollution risk perception have positive effects on their PEB; second, Chinese farmers' household income level positively moderates the relationships between their FP, LP and CP and their PEB but its moderating effect on the relationship between their RBAP and their PEB is not significant. Relevant theory and policy implications for environmental management are discussed in the paper.

Parental occupational exposure to pesticides and risk of childhood cancer in Switzerland: a census-based cohort study

BACKGROUND

Pesticide exposure is a suspected risk factor for childhood cancer. We investigated the risk of developing childhood cancer in relation to parental occupational exposure to pesticides in Switzerland for the period 1990-2015.

METHODS

From a nationwide census-based cohort study in Switzerland, we included children aged < 16 years at national censuses of 1990 and 2000 and followed them until 2015. We extracted parental occupations reported at the census closest to the birth year of the child and estimated exposure to pesticides using a job exposure matrix. Cox proportional hazards models, adjusted for potential confounders, were fitted for the following outcomes: any cancer, leukaemia, central nervous system tumours (CNST), lymphoma, non-CNS solid tumours.

RESULTS

Analyses of maternal (paternal) exposure were based on approximately 15.9 (15.1) million-person years at risk and included 1891 (1808) cases of cancer, of which 532 (503) were leukaemia, 348 (337) lymphomas, 423 (399) CNST, and 588 (569) non-CNS solid tumours. The prevalence of high likelihood of exposure was 2.9% for mothers and 6.7% for fathers. No evidence of an association was found with maternal or paternal exposure for any of the outcomes, except for "non-CNS solid tumours" (High versus None; Father: adjusted HR [95%CI] =1.84 [1.31-2.58]; Mother: 1.79 [1.13-2.84]). No evidence of an association was found for main subtypes of leukaemia and lymphoma. A post-hoc analysis on frequent subtypes of "non-CNS solid tumours" showed positive associations with wide CIs for some cancers.

CONCLUSION

Our study suggests an increased risk for solid tumours other than in the CNS among children whose parents were occupationally exposed to pesticides; however, the small numbers of cases limited a closer investigation of cancer subtypes. Better exposure assessment and pooled studies are needed to further explore a possible link between specific childhood cancers types and parental occupational exposure to pesticides.

Parental occupational exposure to pesticides, animals and organic dust and risk of childhood leukemia and central nervous system tumors: Findings from the International Childhood Cancer Cohort Consortium (I4C)

Parental occupational exposures to pesticides, animals and organic dust have been associated with an increased risk of childhood cancer based mostly on case-control studies. We prospectively evaluated parental occupational exposures and risk of childhood leukemia and central nervous system (CNS) tumors in the International Childhood Cancer Cohort Consortium. We pooled data on 329,658 participants from birth cohorts in five countries (Australia, Denmark, Israel, Norway and United Kingdom). Parental occupational exposures during pregnancy were estimated by linking International Standard Classification of Occupations-1988 job codes to the ALOHA+ job exposure matrix. Risk of childhood (<15 years) acute lymphoblastic leukemia (ALL; n = 129), acute myeloid leukemia (AML; n = 31) and CNS tumors (n = 158) was estimated using Cox proportional hazards models to generate hazard ratios (HR) and 95% confidence intervals (CI). Paternal exposures to pesticides and animals were associated with increased risk of childhood AML (herbicides HR = 3.22, 95% CI = 0.97-10.68; insecticides HR = 2.86, 95% CI = 0.99-8.23; animals HR = 3.89, 95% CI = 1.18-12.90), but not ALL or CNS tumors. Paternal exposure to organic dust was positively associated with AML (HR = 2.38 95% CI = 1.12-5.07), inversely associated with ALL (HR = 0.55, 95% CI = 0.31-0.99) and not associated with CNS tumors. Low exposure prevalence precluded evaluation of maternal pesticide and animal exposures; we observed no significant associations with organic dust exposure. This first prospective analysis of pooled birth cohorts and parental occupational exposures provides evidence for paternal agricultural exposures as childhood AML risk factors. The different risks for childhood ALL associated with maternal and paternal organic dust exposures should be investigated further.

Exploring a potential mechanistic role of DNA methylation in the relationship between in utero and post-natal environmental exposures and risk of childhood acute lymphoblastic leukaemia

The aetiology of childhood acute lymphoblastic leukaemia (ALL) is unclear. Genetic abnormalities have been identified in a number of ALL cases, although these alone are not sufficient for leukaemic transformation. Various in utero and post-natal environmental exposures have been suggested to alter risk of childhood ALL. DNA methylation patterns can be influenced by environmental exposures, and are reported to be altered in ALL, suggesting a potential mediating mechanism between environment and ALL disease risk. To investigate this, we used a 'meet in the middle' approach, investigating the overlap between exposure-associated and disease-associated methylation change. Genome-wide DNA methylation changes in response to possible ALL-risk exposures (i.e. breast feeding, infection history, day care attendance, maternal smoking, alcohol, caffeine, folic acid, iron and radiation exposure) were investigated in a sub-population of the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort using an epigenome-wide association study (EWAS) approach (n = 861-927), and compared to a list of ALL disease-associated methylation changes compiled from published data. Hypergeometric probability tests suggested that the number of directionally concordant gene methylation changes observed in ALL disease and in response to the following exposures; maternal radiation exposure (p = 0.001), alcohol intake (p = 0.006); sugary caffeinated drink intake during pregnancy (p = 0.045); and infant day care attendance (p = 0.003), were not due to chance. Data presented suggests that DNA methylation may be one mediating mechanism in the multiple hit pathway needed for ALL disease manifestation.

Association of Occupational Pesticide Exposure With Immunochemotherapy Response and Survival Among Patients With Diffuse Large B-Cell Lymphoma

IMPORTANCE

Professional use of pesticides is a risk factor for non-Hodgkin lymphoma. The main biological mechanisms of pesticides and chemotherapy are genotoxicity and reactive oxygen species generation. Cellular adaptation among patients exposed to low doses of genotoxic and oxidative compounds might hinder chemotherapy efficiency in patients with lymphoma.

OBJECTIVE

To examine the association of occupational exposure to pesticides with immunochemotherapy response and survival among patients treated for diffuse large B-cell lymphoma.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study assessed patients treated from July 1, 2010, to May 31, 2015, for diffuse large B-cell lymphoma, with a 2-year follow-up. The study took place at 6 university and nonuniversity hospitals in Languedoc-Roussillon, France. A total of 404 patients with newly diagnosed diffuse large B-cell lymphoma treated with anthracycline-based immunochemotherapy were included before the study began. Occupational history was reconstructed for 244 patients and analyzed with the PESTIPOP French job-exposure matrix to determine likelihood of occupational exposure to pesticides. Analysis of the data was performed from July 15, 2017, to July 15, 2018.

MAIN OUTCOMES AND MEASURES

Treatment failure (ie, partial response, stable disease, disease progression, or interruption for toxic effects) rate, 2-year event-free survival, and overall survival between exposed and nonexposed patients after adjustment for confounding factors.

RESULTS

A total of 244 patients (mean [SD] age, 61.3 [15.2] years; 153 [62.7%] male) had complete occupational data. Of these patients, 67 (27.4%) had occupational exposure to pesticides, with 38 exposed through agricultural occupations. Occupational exposure was not associated with clinical and biological characteristics at diagnosis. Occupationally exposed patients had a significantly higher treatment failure rate (22.4% vs 11.3%; P = .03; adjusted odds ratio [AOR] for confounding factors, 3.0; 95% CI, 1.3-6.9); this difference was higher among patients with exposing agricultural occupations compared with other patients (29.0% vs 11.7%; AOR, 5.1; 95% CI, 2.0-12.8). Two-year event-free survival was 70% in the occupationally exposed group vs 82% in the unexposed group (adjusted hazard ratio [AHR] for confounding factors, 2.2; 95% CI, 1.3-3.9). Among patients with exposing agricultural occupations compared with other patients, the difference was more pronounced (2-year event-free survival, 56% vs 83%; AHR, 3.5; 95% CI, 1.9-6.5). Similarly, 2-year overall survival was lower in the group of patients with exposing agricultural occupations compared with other patients (81% vs 92%; AHR, 3.9; 95% CI, 1.5-10.0).

CONCLUSIONS AND RELEVANCE

This retrospective study showed that agricultural occupational exposure to pesticides was associated with treatment failure, event-free survival, and overall survival among patients with diffuse large B-cell lymphoma.

Maternal prenatal exposure to environmental factors and risk of childhood acute lymphocytic leukemia: A hospital-based case-control study in China

OBJECTIVE

To investigate an association between maternal prenatal exposure to several environmental factors and risk of childhood acute lymphocytic leukemia (ALL), and the possible interactions in the Chinese population.

METHODS

345 cases with ALL and their 1:1 age, gender, residence region matched controls aged 0-15 years were recruited from four hospitals in Henan Province from 2014 to 2016. Information was collected by interviews using a questionnaire. Unconditional logistic regression adjusted for age, gender, residence region and relevant confounders was carried out to generate the odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Our data indicate that maternal prenatal exposure to interior housing renovation (adjusted OR: 2.98, 95% CI: 1.51-5.86) or pesticides (adjusted OR: 1.48, 95% CI: 1.67-2.28) increased the risk of childhood ALL. Various subgroup analyses stratified by child's gender, age at diagnosis and other factors also supported these results. However, no interaction was detected between exposure to internal housing renovation and pesticides using an additive model. No significant links between maternal exposures to, environmental tobacco smoking (ETS), antipyretic analgesia intake, or viral infectious diseases with risk of ALL were detected.

CONCLUSION

Findings in our study are in line with the existing literatures, which support the hypothesis that maternal prenatal exposure to interior housing renovation and pesticides are risk factors for childhood ALL. Notably, we found no interaction between these two risk factors, these findings may inform prevention and early detection strategies.

Differences in incidence and survival to childhood cancer between rural and urban areas in Castilla y León, Spain (2003-2014): A Strobe-compliant study

The aim of this study is to describe childhood cancer incidence and survival in Castilla y León (Spain) for the period 2003 to 2014 and to explore differences between rural and urban areas.We made a cohort study in the childhood population of our region for the period of years referred before. Age-adjusted incidence rates to the world standard population (ASRw) were calculated by direct method, and their comparisons were made using incidence rate rations. Survival proportions were calculated by Kaplan-Meier method and their comparisons with log-rank test. The median childhood population less than 15 years old was 296,776 children. A total of 615 cases were recorded from the population-based Childhood Cancer Registry, including all malignant and benign tumors of the central nervous system.Age-standardized incidence rates for all cancers were 176.6 per million. Leukemia incidence rates were highest in rural areas (51.08/million) than in urban areas (33.65/million; P = .018), and by age groups; these differences only remained at age 0 to 4 years with higher rural leukemia incidence (67.13/million) than in urban areas (39.32/million; P = .05). There were no statistically significant differences between rural and urban areas for lymphomas, central nervous system, and all other malignant solid tumors grouped. The 5-year overall survival rate for all patients was 84%, similar to other developed countries, with greater survival in rural areas (88%) compared with urban areas (80%; P = .033). The analysis by tumor groups showed a greater survival rate in rural areas for all the groups, although these differences only reached statistical significance in the group of leukemias, with a survival rate of 90% for rural areas compared with 76% for urban areas (P = .01). Analyzing survival rate by age groups in leukemias only significant survival differences at 10 to 14 years were encountered.We found a higher incidence of leukemia in girls, mainly in rural areas, and also a better survival rate in children diagnosed with leukemia belonging to this population area. Future studies that analyze these facts in similar populations can help us clarify what genetic, epigenetic and environmental factors influence our population and are responsible for these findings.

An overview of disparities in childhood cancer: Report on the Inaugural Symposium on Childhood Cancer Health Disparities, Houston, Texas, 2016

The Inaugural Symposium on Childhood Cancer Health Disparities was held in Houston, Texas, on November 2, 2016. The symposium was attended by 109 scientists and clinicians from diverse disciplinary backgrounds with interests in pediatric cancer disparities and focused on reviewing our current knowledge of disparities in cancer risk and outcomes for select childhood cancers. Following a full day of topical sessions, everyone participated in a brainstorming session to develop a working strategy for the continued expansion of research in this area. This meeting was designed to serve as a springboard for examination of childhood cancer disparities from a more unified and systematic approach and to enhance awareness of this area of need.

Silicone Wristband Passive Samplers Yield Highly Individualized Pesticide Residue Exposure Profiles

Monitoring human exposure to pesticides and pesticide residues (PRs) remains crucial for informing public health policies, despite strict regulation of plant protection product and biocide use. We used 72 low-cost silicone wristbands as noninvasive passive samplers to assess cumulative 5-day exposure of 30 individuals to polar PRs. Ethyl acetate extraction and LC-MS/MS analysis were used for the identification of PRs. Thirty-one PRs were detected of which 15 PRs (48%) were detected only in worn wristbands, not in environmental controls. The PRs included 16 fungicides (52%), 8 insecticides (26%), 2 herbicides (6%), 3 pesticide derivatives (10%), 1 insect repellent (3%), and 1 pesticide synergist (3%). Five detected pesticides were not approved for plant protection use in the EU. Smoking and dietary habits that favor vegetable consumption were associated with higher numbers and higher cumulative concentrations of PRs in wristbands. Wristbands featured unique PR combinations. Our results suggest both environment and diet contributed to PR exposure in our study group. Silicone wristbands could serve as sensitive passive samplers to screen population-wide cumulative dietary and environmental exposure to authorized, unauthorized and banned pesticides.

Evaluation of genotoxic effects in Brazilian agricultural workers exposed to pesticides and cigarette smoke using machine-learning algorithms

Monitoring exposure to xenobiotics by biomarker analyses, such as a micronucleus assay, is extremely important for the precocious detection and prevention of diseases, such as oral cancer. The aim of this study was to evaluate genotoxic effects in rural workers who were exposed to cigarette smoke and/or pesticides and to identify possible classification patterns in the exposure groups. The sample included 120 participants of both sexes aged between 18 and 39, who were divided into the following four groups: control group (CG), smoking group (SG), pesticide group (PG), and smoking + pesticide group (SPG). Their oral mucosa cells were stained with Giemsa for cytogenetic analysis. The total numbers of nuclear abnormalities (CG = 27.16 ± 14.32, SG = 118.23 ± 74.78, PG = 184.23 ± 52.31, and SPG = 191.53 ± 66.94) and micronuclei (CG = 1.46 ± 1.40, SG = 12.20 ± 10.79, PG = 21.60 ± 8.24, and SPG = 20.26 ± 12.76) were higher (p < 0.05) in the three exposed groups compared to the GC. In this study, we considered several different classification algorithms (the artificial neural network, K-nearest neighbors, support vector machine, and optimum path forest). All of the algorithms displayed good classification (accuracy > 80%) when using dataset2 (without the redundant exposure type SPG). It is clear that the data form a robust pattern and that classifiers could be successfully trained on small datasets from the exposure groups. In conclusion, exposing agricultural workers to pesticides and/or tobacco had genotoxic potential, but concomitant exposure to xenobiotics did not lead to additive or potentiating effects.