Assessment of environmental exposures from agricultural pesticides in childhood leukaemia studies: challenges and opportunities

Hepatoprotective and Antioxidant Effects of Nanopiperine against Cypermethrin via Mitigation of Oxidative Stress, Inflammations and Gene Expression Using qRT-PCR

Cypermethrin (Cyp) is a pyrethroid that has been associated with the toxicity of various organs. The aim of our study was to evaluate the hepatoprotective and antioxidant activities of nano-piperine (NP) against Cyp toxicity. Cyp (50 mg/kg) was administered orally in all animals of groups III-VI for 15 days. Groups IV-VI each received three doses of NP (125, 250, and 500 µg/kg/day) for 10 days after receiving the Cyp dosage, which was given after 1 h. A rise in serum biomarkers (ALT, AST, ALP, total protein, and albumin), which are indicators of toxicity alongside anomalous oxidative stress indices (lipid peroxidation (LPO), glutathione (GSH), superoxide dismutase (SOD) and catalase), was detected. After Cyp treatment, we observed upregulated cytokines, caspase expression, and histological analysis that the showed distortion of cell shape. However, the administration of NP dramatically reversed all of the Cyp-induced alterations, inducing reductions in serum marker levels, stress level, the production of cytokines, and caspase expression. Additionally, all of the histopathological alterations were minimized to values that were comparable to normal levels. The present findings suggested that NP exhibits potent antioxidant and anti-inflammatory activities that can protect rats' livers against Cyp-induced liver damage through hepatoprotective activities.

Passive environmental residential exposure to agricultural pesticides and hematological malignancies in the general population: a systematic review

Incidence rates of hematological malignancies have been constantly increasing over the past 40 years. In parallel, an expanding use of agricultural pesticides has been observed. Only a limited number of studies investigated the link between hematological malignancies risk and passive environmental residential exposure to agricultural pesticides in the general population. The purpose of our review was to summarize the current state of knowledge on that question. A systematic literature search was conducted using PubMed and Scopus databases. We built a scoring scale to appraise relevance of each selected articles. We included 23 publications: 13 ecological studies, 9 case-control studies and a cohort study. Positive associations were reported between hematological malignancies and individual pesticides, pesticide groups, all pesticides without distinction, or some crop types. Relevance score was highly various across studies regardless of their design. Children studies were the majority and had overall higher relevance scores. The effect of passive environmental residential exposure to agricultural pesticides on hematological malignancies risk is suggested by the literature. The main limitation of the literature available is the high heterogeneity across studies, especially in terms of exposure assessment approach. Further studies with high methodological relevance should be conducted.

Environmental Risk Factors Implicated in Liver Disease: A Mini-Review

Liver disease is a global health issue, resulting in about two million deaths per year. It encompasses a wide spectrum of varied or unknown etiologies, ranging from lifestyle choices to pre-existing comorbidities. In recent decades, exposure to environmental toxins and subsequent liver health outcomes have captured public interest, due to the extensive application of pesticides, consumption of aflatoxin contaminated foodstuff, and cyanobacterial harmful algae blooms in endemic regions of liver disease. Hepatocellular carcinoma is a serious and debilitating condition of the liver, characterized by abdominal pain and unexplained weight loss. Established risk factors for hepatocellular carcinoma include alcohol consumption, cigarette smoking, and viral infections of hepatitis B and C. However, mounting evidence suggests that environmental toxins may represent an important contributing factor in hepatocellular carcinoma development. This mini-review synthesizes epidemiological investigations, providing evidence for environmental toxins as one potential risk factor for liver disease.

Agricultural and domestic pesticides in house dust from different agricultural areas in France

Pesticides have been associated with various pathologies, and there is growing evidence of pesticide presence in domestic environments. However, most available studies focused on a limited number of pesticides or households, and few have been conducted in Europe. We aimed to assess indoor pesticide contamination by screening the prevalence of 276 pesticides and ten pesticide metabolites, in French households from different agricultural and urban areas. We sampled indoor dust from 239 households in 2012, proximate to orchards (n = 69), cereals (n = 66) and vineyard (n = 68) crops, or from urban area (n = 36). we used cellulose wipes moistened with isopropanol and polypropylene dust traps to collect recent (7 and 30 days, respectively) and settled dust (> 6 months). Overall, 125 pesticides and piperonyl butoxide were detected at least once in households, mostly at low prevalence: 97 in recent dust, and 111 in settled dust. In recent dust, the most prevalent compounds were o-phenylphenol (168 households, 70%), pentachlorophenol (86, 36%), and piperonyl butoxide (82, 34%). In addition to agricultural pesticides, we found a high proportion of domestic and banned compounds in recent and settled house dust. Several pesticides were identified in house dust, from different pesticide groups and sources. Our results suggest that domestic usage and persistence of banned pesticides may contribute substantially to indoor pesticide contamination. Graphical abstract 97 pesticides detected in households' recent indoor dust.

Indoor contamination from pesticides used for outdoor insect control

The present study assessed the indoor level of pesticide residue contamination at a total of 45 dwelling facilities in 5 cities of South Korea from June to November 2014. Pesticide residue contamination was assessed by measuring the frequency and concentration of chlorpyrifos, dichlorvos, and cypermethrin residues in airborne particles, indoor dust, and surface wipes. A preparatory test showed a decreasing tendency in the concentrations of pesticide residues in indoor air over time: from 0.458 to 0.073mg/m³ in dichlorvos for 4weeks and from below 0.050mg/m³ to non-detection in the other substances for 2weeks. Then, pesticide residues were detected indoors 4weeks after outdoor chemical control, implying the infiltration of pesticide particles from outdoors. Airborne particles of dichlorvos were found at a higher level (74.4% of samples at a concentration of 0.053mg/m³), whereas those of the other substances were detected at lower levels (6.1% at 0.002mg/m³ in chlorpyrifos and 9.4% at 0.022mg/m³ in cypermethrin). There was no consistent tendency in the indoor levels of pesticide residue contamination according to dwelling types or indoor height. The indoor levels of dichlorvos residue contamination were lower in industrial districts than in urban or rural districts: 63.9% and 0.013mg/m³ for airborne particles, 13.3% and 0.002μg/g for indoor dust, and 6.7% and 0.001mg/cm² for surface wipes, respectively. There were no significant differences in the indoor levels of pesticide residue contamination between urban and rural districts. The current study found that most dwelling facilities managed their indoor levels of pesticide residue contamination below permissible exposure limit (PEL, 1.0mg/m³) or threshold limit value (TVL, 0.1mg/m³), whereas some facilities did not. So, we suggest that certain guidelines should be drawn up regarding the indoor environment management.

Pesticide exposure assessed through agricultural crop proximity and risk of amyotrophic lateral sclerosis

BACKGROUND

Epidemiologic studies have raised the possibility that some pesticide compounds induce the neurodegenerative disease amyotrophic lateral sclerosis (ALS), though the available evidence is not entirely consistent.

METHODS

We conducted a population-based case-control study in two Italian populations to assess the extent to which residence in the vicinity of agricultural crops associated with the application of neurotoxic pesticides is a risk factor for ALS, using crop acreage in proximity to the residence as an index of exposure.

RESULTS

Based on 703 cases and 2737 controls, we computed an ALS odds ratio of 0.92 (95% confidence interval 0.78-1.09) for those in proximity to agricultural land. Results were not substantially different when using alternative exposure categories or when analyzing specific crop types, with the exception of a higher risk related to exposure to citrus orchards and olive groves in Southern Italy, though based on few exposed subjects (N = 89 and 8, respectively). There was little evidence of any dose-response relation between crop proximity and ALS risk, and using long-term residence instead of current residence did not substantially change our estimates.

CONCLUSIONS

Though our index of exposure is indirect and subject to considerable misclassification, our results offer little support for the hypothesis that neurotoxic pesticide exposure increases ALS risk.

Relative Contributions of Agricultural Drift, Para-Occupational, and Residential Use Exposure Pathways to House Dust Pesticide Concentrations: Meta-Regression of Published Data

BACKGROUND

Increased pesticide concentrations in house dust in agricultural areas have been attributed to several exposure pathways, including agricultural drift, para-occupational, and residential use.

OBJECTIVE

To guide future exposure assessment efforts, we quantified relative contributions of these pathways using meta-regression models of published data on dust pesticide concentrations.

METHODS

From studies in North American agricultural areas published from 1995 to 2015, we abstracted dust pesticide concentrations reported as summary statistics [e.g., geometric means (GM)]. We analyzed these data using mixed-effects meta-regression models that weighted each summary statistic by its inverse variance. Dependent variables were either the log-transformed GM (drift) or the log-transformed ratio of GMs from two groups (para-occupational, residential use).

RESULTS

For the drift pathway, predicted GMs decreased sharply and nonlinearly, with GMs 64% lower in homes 250 m versus 23 m from fields (interquartile range of published data) based on 52 statistics from seven studies. For the para-occupational pathway, GMs were 2.3 times higher [95% confidence interval (CI): 1.5, 3.3; 15 statistics, five studies] in homes of farmers who applied pesticides more recently or frequently versus less recently or frequently. For the residential use pathway, GMs were 1.3 (95% CI: 1.1, 1.4) and 1.5 (95% CI: 1.2, 1.9) times higher in treated versus untreated homes, when the probability that a pesticide was used for the pest treatment was 1-19% and ≥ 20%, respectively (88 statistics, five studies).

CONCLUSION

Our quantification of the relative contributions of pesticide exposure pathways in agricultural populations could improve exposure assessments in epidemiologic studies. The meta-regression models can be updated when additional data become available. Citation: Deziel NC, Beane Freeman LE, Graubard BI, Jones RR, Hoppin JA, Thomas K, Hines CJ, Blair A, Sandler DP, Chen H, Lubin JH, Andreotti G, Alavanja MC, Friesen MC. 2017. Relative contributions of agricultural drift, para-occupational, and residential use exposure pathways to house dust pesticide concentrations: meta-regression of published data. Environ Health Perspect 125:296-305; http://dx.doi.org/10.1289/EHP426.

Passive exposure to agricultural pesticides and risk of childhood leukemia in an Italian community

BACKGROUND

Exposure to pesticides has been suggested as a risk factor for childhood leukemia, but definitive evidence on this relation and the specific pesticides involved is still not clear.

OBJECTIVE

We carried out a population-based case-control study in a Northern Italy community to assess the possible relation between passive exposure to agricultural pesticides and risk of acute childhood leukemia.

METHODS

We assessed passive pesticide exposure of 111 childhood leukemia cases and 444 matched controls by determining density and type of agricultural land use within a 100-m radius buffer around children's homes. We focused on four common crop types, arable, orchard, vineyard and vegetable, characterized by the use of specific pesticides that are potentially involved in childhood induced leukemia. The use of these pesticides was validated within the present study. We computed the odds ratios (OR) of the disease and their 95% confidence intervals (CI) according to type and density of crops around the children's homes, also taking into account traffic pollution and high-voltage power line magnetic field exposure.

RESULTS

Childhood leukemia risk did not increase in relation with any of the crop types with the exception of arable crops, characterized by the use of 2.4-D, MCPA, glyphosate, dicamba, triazine and cypermethrin. The very few children (n=11) residing close to arable crops had an OR for childhood leukemia of 2.04 (95% CI 0.50-8.35), and such excess risk was further enhanced among children aged <5 years.

CONCLUSIONS

Despite the null association with most crop types and the statistical imprecision of the estimates, the increased leukemia risk among children residing close to arable crops indicates the need to further investigate the involvement in disease etiology of passive exposure to herbicides and pyrethroids, though such exposure is unlikely to play a role in the vast majority of cases.

Pesticide exposure and hepatocellular carcinoma risk: A case-control study using a geographic information system (GIS) to link SEER-Medicare and California pesticide data

BACKGROUND

Hepatocellular carcinoma (HCC), the most common type of primary liver cancer, is associated with low survival. U.S. studies examining self-reported pesticide exposure in relation to HCC have demonstrated inconclusive results. We aimed to clarify the association between pesticide exposure and HCC by implementing a novel data linkage between Surveillance, Epidemiology, and End Results (SEER)-Medicare and California Pesticide Use Report (PUR) data using a geographic information system (GIS).

METHODS

Controls were frequency-matched to HCC cases diagnosed between 2000 and 2009 in California by year, age, race, sex, and duration of residence in California. Potential confounders were extracted from Medicare claims. From 1974 to 2008, pounds (1 pound represents 0.45 kg) of applied organophosphate, organochlorine, and carbamate pesticides provided in PURs were aggregated to the ZIP Code level using area weighting in a GIS. ZIP Code exposure estimates were linked to subjects using Medicare-provided ZIP Codes to calculate pesticide exposure. Agricultural residents were defined as living in ZIP Codes with a majority area intersecting agricultural land cover according to the 1992, 2001, and 2006 National Land Cover Database (NLCD) rasters. Multivariable conditional logistic regression was used to estimate the association between pesticide exposure and HCC.

RESULTS

Among California residents of agriculturally intensive areas, previous annual ZIP Code-level exposure to over 14.53 kg/km(2) of organochlorine pesticides (75(th) percentile among controls) was associated with an increased risk of HCC after adjusting for liver disease and diabetes (adjusted odds ratio [OR] 1.87, 95% confidence interval [CI] 1.17, 2.99; p=0.0085). ZIP Code-level organochlorines were significantly associated with an increased risk of HCC among males (adjusted OR 2.76, 95% CI 1.58, 4.82; p=0.0004), but not associated with HCC among females (adjusted OR 0.83, 95% CI 0.35, 1.93; p=0.6600) (interaction p=0.0075).

CONCLUSIONS

This is the first epidemiologic study to use GIS-based exposure estimates to study pesticide exposure and HCC. Our results suggest that organochlorine pesticides are associated with an increase in HCC risk among males but not females.

Household pesticide exposure and the risk of childhood acute leukemia in Shanghai, China

Childhood acute leukemia (AL) is the most common malignant tumor in children, but its etiology remains largely unknown. We investigated the relationship between household exposure to pesticides and childhood AL. Between 2009 and 2010 in Shanghai, a total of 248 newly diagnosed cases of AL and 111 gender-, age-, and hospital-matched controls were included. Five nonspecific dialkyl phosphate (DAP) metabolites of organophosphate pesticides (OPPs) [including dimethyl phosphate (DMP), diethyl phosphate (DEP), dimethyl thiophosphate (DMTP), diethyl thiophosphate (DETP), and diethyl dithiophosphate (DEDTP)] in the urine were analyzed by gas chromatography. The results showed that the median DMP, DEP, DMTP, DETP, and DEDEP levels adjusted for creatinine (Cr) in cases (13.2, 10.0, 31.3, 8.5, and 6.1 μg g(-1), respectively) were all significantly elevated compared with those in controls (3.6, 3.6, 13.3, 2.7, and 1.7 μg g(-1), respectively) (P < 0.05). The household use of mosquito repellent was significantly associated with an increased risk of childhood AL (odds ratio (OR) = 1.9; 95% confidence interval (CI) 1.2-3.1). Moreover, higher exposures were significantly associated with an elevated risk of childhood AL for DMs, DEs, and DAPs. Our findings support the notion that the household use of pesticides may play a role in the etiology of childhood AL and provide some evidence to warrant further investigation of the link between household pesticide exposures and childhood AL in Shanghai.

A review of nonoccupational pathways for pesticide exposure in women living in agricultural areas

BACKGROUND

Women living in agricultural areas may experience high pesticide exposures compared with women in urban or suburban areas because of their proximity to farm activities.

OBJECTIVE

Our objective was to review the evidence in the published literature for the contribution of nonoccupational pathways of pesticide exposure in women living in North American agricultural areas.

METHODS

We evaluated the following nonoccupational exposure pathways: paraoccupational (i.e., take-home or bystander exposure), agricultural drift, residential pesticide use, and dietary ingestion. We also evaluated the role of hygiene factors (e.g., house cleaning, shoe removal).

RESULTS

Among 35 publications identified (published 1995-2013), several reported significant or suggestive (p < 0.1) associations between paraoccupational (n = 19) and agricultural drift (n = 10) pathways and pesticide dust or biomarker levels, and 3 observed that residential use was associated with pesticide concentrations in dust. The 4 studies related to ingestion reported low detection rates of most pesticides in water; additional studies are needed to draw conclusions about the importance of this pathway. Hygiene factors were not consistently linked to exposure among the 18 relevant publications identified.

CONCLUSIONS

Evidence supported the importance of paraoccupational, drift, and residential use pathways. Disentangling exposure pathways was difficult because agricultural populations are concurrently exposed to pesticides via multiple pathways. Most evidence was based on measurements of pesticides in residential dust, which are applicable to any household member and are not specific to women. An improved understanding of nonoccupational pesticide exposure pathways in women living in agricultural areas is critical for studying health effects in women and for designing effective exposure-reduction strategies.

Temporal variability of pesticide concentrations in homes and implications for attenuation bias in epidemiologic studies

BACKGROUND

Residential pesticide exposure has been linked to adverse health outcomes in adults and children. High-quality exposure estimates are critical for confirming these associations. Past epidemiologic studies have used one measurement of pesticide concentrations in carpet dust to characterize an individual's average long-term exposure. If concentrations vary over time, this approach could substantially misclassify exposure and attenuate risk estimates.

OBJECTIVES

We assessed the repeatability of pesticide concentrations in carpet dust samples and the potential attenuation bias in epidemiologic studies relying on one sample.

METHODS

We collected repeated carpet dust samples (median = 3; range, 1-7) from 21 homes in Fresno County, California, during 2003-2005. Dust was analyzed for 13 pesticides using gas chromatography-mass spectrometry. We used mixed-effects models to estimate between- and within-home variance. For each pesticide, we computed intraclass correlation coefficients (ICCs) and the estimated attenuation of regression coefficients in a hypothetical case-control study collecting a single dust sample.

RESULTS

The median ICC was 0.73 (range, 0.37-0.95), demonstrating higher between-home than within-home variability for most pesticides. The expected magnitude of attenuation bias associated with using a single dust sample was estimated to be ≤ 30% for 7 of the 13 compounds evaluated.

CONCLUSIONS

For several pesticides studied, use of one dust sample to represent an exposure period of approximately 2 years would not be expected to substantially attenuate odds ratios. Further study is needed to determine if our findings hold for longer exposure periods and for other pesticides.

Environmental exposure assessment in European birth cohorts: results from the ENRIECO project

Environmental exposures during pregnancy and early life may have adverse health effects. Single birth cohort studies often lack statistical power to tease out such effects reliably. To improve the use of existing data and to facilitate collaboration among these studies, an inventory of the environmental exposure and health data in these studies was made as part of the ENRIECO (Environmental Health Risks in European Birth Cohorts) project. The focus with regard to exposure was on outdoor air pollution, water contamination, allergens and biological organisms, metals, pesticides, smoking and second hand tobacco smoke (SHS), persistent organic pollutants (POPs), noise, radiation, and occupational exposures. The review lists methods and data on environmental exposures in 37 European birth cohort studies. Most data is currently available for smoking and SHS (N=37 cohorts), occupational exposures (N=33), outdoor air pollution, and allergens and microbial agents (N=27). Exposure modeling is increasingly used for long-term air pollution exposure assessment; biomonitoring is used for assessment of exposure to metals, POPs and other chemicals; and environmental monitoring for house dust mite exposure assessment. Collaborative analyses with data from several birth cohorts have already been performed successfully for outdoor air pollution, water contamination, allergens, biological contaminants, molds, POPs and SHS. Key success factors for collaborative analyses are common definitions of main exposure and health variables. Our review emphasizes that such common definitions need ideally be arrived at in the study design phase. However, careful comparison of methods used in existing studies also offers excellent opportunities for collaborative analyses. Investigators can use this review to evaluate the potential for future collaborative analyses with respect to data availability and methods used in the different cohorts and to identify potential partners for a specific research question.

Residential pesticides and childhood leukemia: a systematic review and meta-analysis

It is a systematic review and meta-analysis of previous observational epidemiologic studies examining the relationship between residential pesticide exposures during critical exposure time windows (preconception, pregnancy, and childhood) and childhood leukemia. Searches of Medline and other electronic databases were performed (1950-2009). Study selection, data abstraction, and quality assessment were performed by two independent reviewers. Random effects models were used to obtain summary odds ratios (ORs) and 95% confidence intervals (Cis). Of the 17 identified studies, 15 were included in the meta-analysis. Exposures during pregnancy to unspecified residential pesticides insecticides, and herbicides were positively associated with childhood leukemia. Exposures during childhood to unspecified residential pesticides and insecticides were also positively associated with childhood leukemia, but there was no association with herbicides. Positive associations were observed between childhood leukemia and residential pesticide exposures. Further work is needed to confirm previous findings based on self-report, to examine potential exposure-response relationships, and to assess specific pesticides and toxicologically related subgroups of pesticides in more detail.

Residential pesticides and childhood leukemia: a systematic review and meta-analysis

OBJECTIVE

We conducted a systematic review and meta-analysis of previous observational epidemiologic studies examining the relationship between residential pesticide exposures during critical exposure time windows (preconception, pregnancy, and childhood) and childhood leukemia.

DATA SOURCES

Searches of MEDLINE and other electronic databases were performed (1950-2009). Reports were included if they were original epidemiologic studies of childhood leukemia, followed a case-control or cohort design, and assessed at least one index of residential/household pesticide exposure/use. No language criteria were applied.

DATA EXTRACTION

Study selection, data abstraction, and quality assessment were performed by two independent reviewers. Random effects models were used to obtain summary odds ratios (ORs) and 95% confidence intervals (CIs).

DATA SYNTHESIS

Of the 17 identified studies, 15 were included in the meta-analysis. Exposures during pregnancy to unspecified residential pesticides (summary OR = 1.54; 95% CI, 1.13-2.11; I2 = 66%), insecticides (OR = 2.05; 95% CI, 1.80-2.32; I2 = 0%), and herbicides (OR = 1.61; 95% CI, 1.20-2.16; I2 = 0%) were positively associated with childhood leukemia. Exposures during childhood to unspecified residential pesticides (OR = 1.38; 95% CI, 1.12-1.70; I2 = 4%) and insecticides (OR = 1.61; 95% CI, 1.33-1.95; I2 = 0%) were also positively associated with childhood leukemia, but there was no association with herbicides.

CONCLUSIONS

Positive associations were observed between childhood leukemia and residential pesticide exposures. Further work is needed to confirm previous findings based on self-report, to examine potential exposure-response relationships, and to assess specific pesticides and toxicologically related subgroups of pesticides in more detail.

Residential proximity to agricultural pesticide applications and childhood acute lymphoblastic leukemia

Ambient exposure from residential proximity to applications of agricultural pesticides may contribute to the risk of childhood acute lymphoblastic leukemia (ALL). Using residential histories collected from the families of 213 ALL cases and 268 matched controls enrolled in the Northern California Childhood Leukemia Study, the authors assessed residential proximity within a half-mile (804.5m) of pesticide applications by linking address histories with reports of agricultural pesticide use. Proximity was ascertained during different time windows of exposure, including the first year of life and the child's lifetime through the date of diagnosis for cases or reference for controls. Agricultural pesticides were categorized a priori into groups based on similarities in toxicological effects, physicochemical properties, and target pests or uses. The effects of moderate and high exposure for each group of pesticides were estimated using conditional logistic regression. Elevated ALL risk was associated with lifetime moderate exposure, but not high exposure, to certain physicochemical categories of pesticides, including organophosphates, chlorinated phenols, and triazines, and with pesticides classified as insecticides or fumigants. A similar pattern was also observed for several toxicological groups of pesticides. These findings suggest future directions for the identification of specific pesticides that may play a role in the etiology of childhood leukemia.