Exposure to professional pest control treatments and the risk of childhood acute lymphoblastic leukemia

Maternal and Paternal Household Pesticide Exposure During Pregnancy and Risk of Childhood Acute Lymphoblastic Leukemia

OBJECTIVE

The aim of this study was to investigate whether risk estimates for childhood acute lymphoblastic leukemia change when restricting model comparison groups to "nonpesticide exposure" (NPE10) households.

METHODS

Cases ( n = 1810) 15 years or younger were identified through Children's Cancer Group institutions between 1989 and 1993 and age-/sex-matched to controls ( n = 1951). Household pesticide use during pregnancy/month prior was collected via telephone. NPE10 comparison group reporting no parental exposure to 10 pesticide classes was identified.

RESULTS

Adjusted odds ratios increased from 15% to 49% when limiting the comparison to NPE10. Maternal termite insecticide exposure was associated with greatest risk (adjusted odds ratio, 4.21; 95% confidence interval, 2.00-8.88). There was minimal evidence of interaction by child sex or occupational pesticide exposure, and no monotonic dose-response pattern with frequency of use (times per year).

CONCLUSIONS

Elevated risks are consistent with published pooled-/meta-analyses and DNA damage. The consistency and magnitude of these associations warrant product labeling, exposure reduction interventions, or both.

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.

Maternal pesticide exposure and its relation to childhood cancer: an umbrella review of meta-analyses

This umbrella review summarizes the available meta-analyses elucidating the effects of maternal pesticide exposure on adverse health outcomes in children particularly the risk of childhood cancer. A literature search was conducted on PubMed and Scopus with 10-years temporal restriction and with search terms of ('pesticides') and ('maternal' or 'pregnancy' or 'gestational' or 'perinatal' or 'children' or 'infants' or 'birth weight' or 'gestational age' or 'cancer' or 'tumor' or 'malignancy' or 'carcinoma') and ('meta-analysis' or 'systematic review'). Using relative risk estimates, e.g., odds ratio (OR), relative risk (RR), ß coefficients, and 95% confidence interval (CI) as a prerequisite for inclusion/exclusion criteria a total of 19 eligible meta-analyses were included. The results showed that maternal domestic/occupational pesticide exposure increases the risk for childhood leukaemia. The overall OR regarding the risk of pesticide exposure and leukaemia was 1.23 to 1.57 with heterogeneity I2 values that varied between 12.9% and 73%. Some studies found that exposure to dichlorodiphenyldichloroethylene (p,p´-DDE) and polychlorinated biphenyls (PCB-153) pesticides appears to decrease infant birth weight to some extent [p,p´-DDE (ß = -0.007 to -0.008)] and [PCB-153 (ß = -0.15 to -0.17)]Needing more studies on this relationship, our study found that pesticide exposure is a risk factor for leukaemia in children.

Exposure to pesticides and childhood leukemia risk: A systematic review and meta-analysis

Despite the abundance of epidemiological evidence concerning the association between pesticide exposure and adverse health outcomes including acute childhood leukemia (AL), evidence remains inconclusive, and is inherently limited by heterogeneous exposure assessment and multiple statistical testing. We performed a literature search of peer-reviewed studies, published until January 2021, without language restrictions. Summary odds ratios (OR) and 95% confidence intervals (CI) were derived from stratified random-effects meta-analyses by type of exposure and outcome, exposed populations and window of exposure to address the large heterogeneity of existing literature. Heterogeneity and small-study effects were also assessed. We identified 55 eligible studies (n = 48 case-control and n = 7 cohorts) from over 30 countries assessing >200 different exposures of pesticides (n = 160,924 participants). The summary OR for maternal environmental exposure to pesticides (broad term) during pregnancy and AL was 1.88 (95%CI: 1.15-3.08), reaching 2.51 for acute lymphoblastic leukemia (ALL; 95%CI: 1.39-4.55). Analysis by pesticide subtype yielded an increased risk for maternal herbicide (OR: 1.41, 95%CI: 1.00-1.99) and insecticide (OR: 1.60, 95%CI: 1.11-2.29) exposure during pregnancy and AL without heterogeneity (p = 0.12-0.34). Meta-analyses of infant leukemia were only feasible for maternal exposure to pesticides during pregnancy. Higher magnitude risks were observed for maternal pesticide exposure and infant ALL (OR: 2.18, 95%CI: 1.44-3.29), and the highest for infant acute myeloid leukemia (OR: 3.42, 95%CI: 1.98-5.91). Overall, the associations were stronger for maternal exposure during pregnancy compared to childhood exposure. For occupational or mixed exposures, parental, and specifically paternal, pesticide exposure was significantly associated with increased risk of AL (ORparental: 1.75, 95%CI: 1.08-2.85; ORpaternal: 1.20, 95%CI: 1.07-1.35). The epidemiological evidence, supported by mechanistic studies, suggests that pesticide exposure, mainly during pregnancy, increases the risk of childhood leukemia, particularly among infants. Sufficiently powered studies using repeated biomarker analyses are needed to confirm whether there is public health merit in reducing prenatal pesticide exposure.

Maternal residential pesticide use and risk of childhood leukemia in Costa Rica

Evidence suggests that early-life exposure to pesticides inside the home may be associated with childhood leukemia, however data from Latin American countries are limited. We examined whether self-reported maternal residential pesticide use and nearby pesticide applications-before and after child's birth-were associated with acute lymphoblastic leukemia (ALL) in the Costa Rican Childhood Leukemia Study (CRCLS), a population-based case-control study (2001-2003). Cases (n = 251 ALL) were diagnosed between 1995 and 2000 (age <15 years at diagnosis) and were identified through the Costa Rican Cancer Registry and National Children's Hospital. Population controls (n = 577) were drawn from the National Birth Registry. We fitted unconditional logistic regression models adjusted for child sex, birth year, and socioeconomic status to estimate the exposure-outcome associations and also stratified by child sex. We observed that self-reported maternal insecticide use inside the home in the year before pregnancy, during pregnancy, and while breastfeeding was associated with increased odds of ALL among boys [adjusted Odds Ratio (aOR) = 1.63 (95% confidence interval [95% CI]: 1.05-2.53), 1.75 (1.13-2.73), and 1.75 (1.12-2.73), respectively. We also found evidence of exposure-response relationships between more frequent maternal insecticide use inside the home and increased odds of ALL among boys and girls combined. Maternal report of pesticide applications on farms or companies near the home during pregnancy and at any time period were also associated with ALL. Our study in Costa Rica highlights the need for education to minimize pesticide exposures inside and around the home, particularly during pregnancy and breastfeeding.

Long-term Recall of Pregnancy-related Events

BACKGROUND

Early-life factors can be associated with future health outcomes and are often measured by maternal recall.

METHODS

We used data from the North Carolina Early Pregnancy Study and Follow-up to characterize long-term maternal recall. We used data from the Early Pregnancy Study as the gold standard to evaluate the accuracy of prepregnancy weight, early pregnancy behaviors, symptoms and duration of pregnancy, and child's birthweight reported at follow-up, for 109 women whose study pregnancies had resulted in a live birth.

RESULTS

Most (81%) participants reported a prepregnancy weight at follow-up that correctly classified them by BMI category. Women reported experiencing pregnancy symptoms later at follow-up than what they reported in the Early Pregnancy Study. Accuracy of reporting of early pregnancy behaviors varied based on exposure. Overall, women who had abstained from a behavior were more likely to be classified correctly. Sensitivity of reporting was 0.14 for antibiotics, 0.30 for wine, 0.71 for brewed coffee, and 0.82 for vitamins. Most misclassification at follow-up was due to false-negative reporting. Among women who gave birth to singletons, 94% could report their child's correct birthweight within ½ pound and 86% could report duration of pregnancy within 7 days at follow-up.

CONCLUSIONS

Self-report of prepregnancy weight, duration of pregnancy, and child's birthweight after almost 30 years was good, whereas self-reported pregnancy-related exposures resulted in higher levels of reporting error. Social desirability appeared to influence women's report of their behaviors at follow-up. Self-reported assessment of confidence in the recalled information was unrelated to accuracy.

Pesticides: an update of human exposure and toxicity

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

Home pesticide exposures and risk of childhood leukemia: Findings from the childhood leukemia international consortium

Some previous studies have suggested that home pesticide exposure before birth and during a child's early years may increase the risk of childhood leukemia. To further investigate this, we pooled individual level data from 12 case-control studies in the Childhood Leukemia International Consortium. Exposure data were harmonized into compatible formats. Pooled analyses were undertaken using multivariable unconditional logistic regression. The odds ratio (ORs) for acute lymphoblastic leukemia (ALL) associated with any pesticide exposure shortly before conception, during pregnancy and after birth were 1.39 (95% confidence interval [CI]: 1.25, 1.55) (using 2,785 cases and 3,635 controls), 1.43 (95% CI: 1.32, 1.54) (5,055 cases and 7,370 controls) and 1.36 (95% CI: 1.23, 1.51) (4,162 cases and 5,179 controls), respectively. Corresponding ORs for risk of acute myeloid leukemia (AML) were 1.49 (95% CI: 1.02, 2.16) (173 cases and 1,789 controls), 1.55 (95% CI: 1.21, 1.99) (344 cases and 4,666 controls) and 1.08 (95% CI: 0.76, 1.53) (198 cases and 2,655 controls), respectively. There was little difference by type of pesticide used. The relative similarity in ORs between leukemia types, time periods and pesticide types may be explained by similar exposure patterns and effects across the time periods in ALL and AML, participants' exposure to multiple pesticides, or recall bias. Although some recall bias is likely, until a better study design can be found to investigate the associations between home pesticide use and childhood leukemia in an equally large sample, it would appear prudent to limit the use of home pesticides before and during pregnancy, and during childhood.

Residential Exposure to Pesticide During Childhood and Childhood Cancers: A Meta-Analysis

CONTEXT

There is an increasing concern about chronic low-level pesticide exposure during childhood and its influence on childhood cancers.

OBJECTIVE

In this meta-analysis, we aimed to examine associations between residential childhood pesticide exposures and childhood cancers.

DATA SOURCES

We searched all observational studies published in PubMed before February 2014 and reviewed reference sections of articles derived from searches.

STUDY SELECTION

The literature search yielded 277 studies that met inclusion criteria.

DATA EXTRACTION

Sixteen studies were included in the meta-analysis. We calculated effect sizes and 95% confidence intervals (CIs) by using a random effect model with inverse variance weights.

RESULTS

We found that childhood exposure to indoor but not outdoor residential insecticides was associated with a significant increase in risk of childhood leukemia (odds ratio [OR] = 1.47; 95% CI, 1.26-1.72; I(2) = 30%) and childhood lymphomas (OR = 1.43; 95% CI, 1.15-1.78; I(2) = 0%). A significant increase in risk of leukemia was also associated with herbicide exposure (OR = 1.26; 95% CI, 1.10-1.44; I(2) = 0%). Also observed was a positive but not statistically significant association between childhood home pesticide or herbicide exposure and childhood brain tumors.

LIMITATIONS

The small number of studies included in the analysis represents a major limitation of the current analysis.

CONCLUSIONS

Results from this meta-analysis indicated that children exposed to indoor insecticides would have a higher risk of childhood hematopoietic cancers. Additional research is needed to confirm the association between residential indoor pesticide exposures and childhood cancers. Meanwhile, preventive measures should be considered to reduce children's exposure to pesticides at home.

Use of Systematic Review and Meta-Analysis in Environmental Health Epidemiology: a Systematic Review and Comparison with Guidelines

Systematic review (SR) and meta-analysis (MA) have potential to contribute substantially to environmental health (EH) risk assessment and policy-making, provided study questions are clear and methods sound. We undertook a systematic review of the published epidemiological literature for studies using both SR and MA examining associations between chronic low-dose chemical exposures and adverse health outcomes in general populations and compared actual methods and reporting with a checklist based on available published guidelines. We identified 48 EH SRMAs meeting these criteria. Associations were mainly positive and statistically significant, often involving large populations. A majority of studies followed most general SRMA guidance, although we identified weaknesses in problem formulation, study search, selection and data extraction, and integrating policy implications. Fewer studies followed EH-specific SRMA recommendations, particularly regarding exposure heterogeneity and other risks of bias. Development and adoption of EH-specific SRMA guidelines would contribute to strengthening these tools for public health decision-making.

Knowing the enemy: ant behavior and control in a pediatric hospital of Buenos Aires

Ant control is difficult in systems even where a variety of control strategies and compounds are allowed; in sensitive places such as hospitals, where there are often restrictions on the methods and toxicants to be applied, the challenge is even greater. Here we report the methods and results of how we faced this challenge of controlling ants in a pediatric hospital using baits. Our strategy was based on identifying the species present and analyzing their behavior. On the one hand, we evaluated outdoors in the green areas of the hospital, the relative abundance of ant genera, their food preferences and the behavioral dominances. On the other hand, control treatments were performed using separately two boron compounds added to sucrose solution which was not highly concentrated to avoid constrains due to the viscosity. Most of the species in the food preference test accepted sugary food; only one species was recorded to visit it less than the protein foods. This result was consistent with the efficacy of control treatments by sugary baits within the rooms. For species that showed good acceptance of sugar solutions in the preference test outdoors, sugar bait control indoors was 100& effective. Conversely, for the only species that foraged significantly less on sugar food, the bait treatment was ineffective. This work reveals the importance of considering the behavior and feeding preferences of the species to be controlled by toxic baits.

Increased cancer burden among pesticide applicators and others due to pesticide exposure

A growing number of well-designed epidemiological and molecular studies provide substantial evidence that the pesticides used in agricultural, commercial, and home and garden applications are associated with excess cancer risk. This risk is associated both with those applying the pesticide and, under some conditions, those who are simply bystanders to the application. In this article, the epidemiological, molecular biology, and toxicological evidence emerging from recent literature assessing the link between specific pesticides and several cancers including prostate cancer, non-Hodgkin lymphoma, leukemia, multiple myeloma, and breast cancer are integrated. Although the review is not exhaustive in its scope or depth, the literature does strongly suggest that the public health problem is real. If we are to avoid the introduction of harmful chemicals into the environment in the future, the integrated efforts of molecular biology, pesticide toxicology, and epidemiology are needed to help identify the human carcinogens and thereby improve our understanding of human carcinogenicity and reduce cancer risk.

Pyrethroid pesticide exposure and risk of childhood acute lymphocytic leukemia in Shanghai

Significant amounts of pyrethroid pesticides are used throughout China. Previous studies have suggested that exposure to pesticides may increase the risk of childhood cancer; however, few studies have focused on pyrethroid metabolites. We investigated five nonspecific metabolites of pyrethroid pesticides found in children's urine and examined the correlation with childhood leukemia. We conducted a hospital-based case-control study of childhood acute lymphocytic leukemia (ALL) in Shanghai between 2010 and 2011. The study included 176 children aged 0-14 years and 180 controls matched for age and sex. Compared with those in the lowest quartiles of total and individual metabolites, the highest quartiles were associated with an approximate 2-fold increased risk of ALL [total metabolites: odds ratio (OR) = 2.75, 95% confidence interval (CI), 1.43-5.29; cis-DCCA: OR = 2.21, 95% CI, 1.16-4.19; trans-DCCA: OR = 2.33, 95% CI, 1.23-4.41; and 3-PBA: OR = 1.84, 95% CI, 1.00-3.38], and most of the positive trends were significant (p < 0.05). Our findings suggest that urinary levels of pyrethroid metabolites may be associated with an elevated risk of childhood ALL and represent a previously unreported quantitative exposure assessment for childhood leukemia.

Total diet study on pesticide residues in France: levels in food as consumed and chronic dietary risk to consumers

Chronic dietary exposure to pesticide residues was assessed for the French population using a total diet study (TDS) to take into account realistic levels in foods as consumed at home (table-ready). Three hundred and twenty-five pesticides and their transformation products, grouped into 283 pesticides according to their residue definition, were sought in 1235 composite samples corresponding to 194 individual food items that cover 90% of the adult and child diet. To make up the composite samples, about 19,000 food products were bought during different seasons from 2007 to 2009 in 36 French cities and prepared according to the food preparation practices recorded in the individual and national consumption survey (INCA2). The results showed that 37% of the samples contained one or more residues. Seventy-three pesticides were detected and 55 quantified at levels ranging from 0.003 to 8.7mg/kg. The most frequently detected pesticides, identified as monitoring priorities in 2006, were the post-harvest insecticides pirimiphos-methyl and chlorpyrifos-methyl-particularly in wheat-based products-together with chlorpyrifos, iprodione, carbendazim and imazalil, mainly in fruit and fruit juices. Dietary intakes were estimated for each subject of INCA2 survey, under two contamination scenarios to handle left-censored data: lower-bound scenario (LB) where undetected results were set to zero, and upper-bound (UB) scenario where undetected results were set to the detection limit. For 90% of the pesticides, exposure levels were below the acceptable daily intake (ADI) under the two scenarios. Under the LB scenario, which tends to underestimate exposure levels, only dimethoate intakes exceeded the ADI for high level consumers of cherry (0.6% of children and 0.4% of adults). This pesticide, authorised in Europe, and its metabolite were detected in both cherries and endives. Under the UB scenario, that overestimates exposure, a chronic risk could not be excluded for nine other pesticides (dithiocarbamates, ethoprophos, carbofuran, diazinon, methamidophos, disulfoton, dieldrin, endrin and heptachlor). For these pesticides, more sensitive analyses of the main food contributors are needed in order to refine exposure assessment.

Maternal consumption of coffee and tea during pregnancy and risk of childhood ALL: results from an Australian case-control study

OBJECTIVES

To investigate whether maternal coffee and/or tea consumption during the last 6 months of pregnancy was associated with risk of childhood ALL.

METHODS

Data on coffee and tea drinking during pregnancy from 337 case mothers and 697 control mothers were analyzed using unconditional multivariable logistic regression. A meta-analysis of our findings with those of previous studies was also conducted.

RESULTS

There was little evidence of an overall association between maternal coffee consumption and risk of ALL: OR 0.89 (95% CI 0.61, 1.30), although there was some suggestion that higher levels of intake might increase the risk in children of non-smoking mothers: OR for 2+ cups/day = 1.44 (95% CI 0.85, 2.42); this was supported by our meta-analysis. Risk was also elevated among cases with chromosomal translocations. The overall OR for maternal tea consumption was 0.82 (95% CI 0.56, 1.18), although the OR for T-cell ALL was 0.21 (95% CI 0.08, 0.51). Among ALL cases with translocations, the ORs for tea consumption tended to be elevated: OR = 1.70 (95% CI 0.79-3.68) for 2+ cups/day.

CONCLUSIONS

The observed increased risk associated with coffee and tea consumption may be confined to ALL with translocations. These associations should be explored further in large international consortia.