Chensheng Lu

Estimating Pesticide Exposure from Dietary Intake and Organic Food Choices: The Multi-Ethnic Study of Atherosclerosis (MESA)

Background Organophosphate pesticide (OP) exposure to the U.S. population is dominated by dietary intake. The magnitude of exposure from diet depends partly on personal decisions such as which foods to eat and whether to choose organic food. Most studies of OP exposure rely on urinary biomarkers, which are limited by short half-lives and often lack specificity to parent compounds. A reliable means of estimating long-term dietary exposure to individual OPs is needed to assess the potential relationship with adverse health effects. Objectives We assessed long-term dietary exposure to 14 OPs among 4,466 participants in the Multi-Ethnic Study of Atherosclerosis, and examined the influence of organic produce consumption on this exposure. Methods Individual-level exposure was estimated by combining information on typical intake of specific food items with average OP residue levels on those items. In an analysis restricted to a subset of participants who reported rarely or never eating organic produce (“conventional consumers”), we assessed urinary dialkylphosphate (DAP) levels across tertiles of estimated exposure (n = 480). In a second analysis, we compared DAP levels across subgroups with differing self-reported organic produce consumption habits (n = 240). Results Among conventional consumers, increasing tertile of estimated dietary OP exposure was associated with higher DAP concentrations (p < 0.05). DAP concentrations were also significantly lower in groups reporting more frequent consumption of organic produce (p < 0.02). Conclusions Long-term dietary exposure to OPs was estimated from dietary intake data, and estimates were consistent with DAP measurements. More frequent consumption of organic produce was associated with lower DAPs. Citation Curl CL, Beresford SA, Fenske RA, Fitzpatrick AL, Lu C, Nettleton JA, Kaufman JD. 2015. Estimating pesticide exposure from dietary intake and organic food choices: the Multi-Ethnic Study of Atherosclerosis (MESA). Environ Health Perspect 123:475–483; http://dx.doi.org/10.1289/ehp.1408197

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; I2 = 30%) and childhood lymphomas (OR = 1.43; 95% CI, 1.15–1.78; I2 = 0%). A significant increase in risk of leukemia was also associated with herbicide exposure (OR = 1.26; 95% CI, 1.10–1.44; I2 = 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.

Within- and Between-Child Variation in Repeated Urinary Pesticide Metabolite Measurements over a 1-Year Period

Background: Children are exposed to pesticides from many sources and routes, including dietary and incidental ingestion, dermal absorption, and inhalation. Linking health outcomes to these exposures using urinary metabolites requires understanding temporal variability within subjects to avoid exposure misclassification. Objectives: We characterized the within- and between-child variability of urinary organophosphorus and pyrethroid metabolites in 23 participants of the Children’s Pesticide Exposure Study–Washington over 1 year and examined the ability of one to four spot urine samples to categorize mean exposures. Methods: Each child provided urine samples twice daily over 7- to 16-day sessions in four seasons in 2003 and 2004. Samples were analyzed for five pyrethroid and five organophosphorus (OP) metabolites. After adjusting for specific gravity, we used a customized maximum likelihood estimation linear mixed-effects model that accounted for values below the limit of detection to calculate intraclass correlation coefficients (ICC) and conducted surrogate category analyses. Results: Within-child variability was 2–11 times greater than between-child variability. When restricted to samples collected during a single season, ICCs were higher in the fall, winter, and spring than in summer for OPs, and higher in summer and winter for pyrethroids, indicating an increase in between-person variability relative to within-person variability during these seasons. Surrogate category analyses demonstrated that a single spot urine sample did not categorize metabolite concentrations well, and that four or more samples would be needed to categorize children into quartiles consistently. Conclusions: Urinary biomarkers of these short half-life pesticides exhibited substantial within-person variability in children observed over four seasons. Researchers investigating pesticides and health outcomes in children may need repeated biomarker measurements to derive accurate estimates of exposure and relative risks. Citation: Attfield KR, Hughes MD, Spengler JD, Lu C. 2014. Within- and between-child variation in repeated urinary pesticide metabolite measurements over a 1-year period. Environ Health Perspect 122:201–206; http://dx.doi.org/10.1289/ehp.1306737

Household Pesticide Contamination from Indoor Pest Control Applications in Urban Low-Income Public Housing Dwellings: A Community-Based Participatory Research

We designed this community-based participatory research (CBPR) project aiming to generate evidence-based research results to encourage residents living in urban low-income public housing dwellings engaging in a community-wide integrated pest management (IPM) program with the intention to improve their health and quality of life, as well as household conditions. We enrolled 20 families and their children in this study in which we utilized environmental exposure assessment (surface wipe and indoor air) tools to quantitatively assessing residential pesticide exposure in young children before the implementation of an IPM program. We analyzed those samples for 19 organophosphate (OP) and pyrethroid pesticides. The most commonly detected pesticides were pyrethroids, particularly permethrin and cypermethrin with average concentrations of 2.47 and 3.87 μg/m(2), respectively. In many dwellings, we detected OPs, which are no longer available on the market; however, their levels are significantly lower than those of pyrethroids. None of the 20 families was free from pesticide contamination in their households, and pesticides were commonly detected in living room and childrens bedroom. The correlation among household hygienic conditions, the sighting of live pests/pest debris, and the degree of indoor pesticide contamination highlights the failure of conventional chemical-based applications for pest controls. The results from the current study, as well as other recent studies, conducted in low-income public housing, child care centers, and randomly selected homes in the U.S. should accentuate the need for alternative pest management programs that incorporate safer and more sustainable protocols for pest controls.

Biological monitoring of diazinon exposure using saliva in an animal model

Alternative biological monitoring methods are currently being pursued to better quantify pesticide exposures. In this study, the feasibility of using saliva as a tool for measuring diazinon exposure was determined in an animal model. Male Spraque-Dawley rats were dosed with 1 or 10 mg/kg diazinon by bolus intravenous injection. Time-matched saliva and arterial blood samples were collected from 10 to 250 min post administration. Diazinon was distributed and eliminated rapidly in rats following intravenous (iv) bolus injection, according to a two-compartmental pharmacokinetic analysis. Salivary concentration of diazinon showed a strong correlation with plasma concentration of diazinon. The saliva/plasma (S/P) concentration ratio of diazinon was not affected by administered dose, sampling time, or salivary flow rate, suggesting that salivary excretion of diazinon in rats is fairly constant. Diazinon concentrations in saliva were consistently lower than those in arterial plasma. The mean S/P concentration ratios of diazinon were 0.16 and 0.13 for 1 and 10 mg/kg iv bolus doses, respectively. It is most likely that the incomplete transfer of diazinon from plasma to saliva is due to protein binding of diazinon in plasma. If the protein-unbound fraction of diazinon in plasma is used to calculate the S/P ratio, the S/P concentration ratio of diazinon is close to unity. The results from this study support the conclusion that diazinon salivary concentrations not only can be used to predict the plasma levels of diazinon in rats, but also reflect the unbound fraction of diazinon in plasma.

The implications of using a physiologically based pharmacokinetic (PBPK) model for pesticide risk assessment.

Background A physiologically based pharmacokinetic (PBPK) model would make it possible to simulate the dynamics of chemical absorption, distribution, metabolism, and elimination (ADME) from different routes of exposures and, in theory, could be used to evaluate associations between exposures and biomarker measurements in blood or urine. Objective We used a PBPK model to predict urinary excretion of 3,5,6-trichloro-2-pyridinol (TCPY), the specific metabolite of chlorpyrifos (CPF), in young children. Methods We developed a child-specific PBPK model for CPF using PBPK models previously developed for rats and adult humans. Data used in the model simulation were collected from 13 children 3–6 years of age who participated in a cross-sectional pesticide exposure assessment study with repeated environmental and biological sampling. Results The model-predicted urinary TCPY excretion estimates were consistent with measured levels for 2 children with two 24-hr duplicate food samples that contained 350 and 12 ng/g of CPF, respectively. However, we found that the majority of model outputs underpredicted the measured urinary TCPY excretion. Conclusions We concluded that the potential measurement errors associated with the aggregate exposure measurements will probably limit the applicability of PBPK model estimates for interpreting urinary TCPY excretion and absorbed CPF dose from multiple sources of exposure. However, recent changes in organophosphorus (OP) use have shifted exposures from multipathways to dietary ingestion only. Thus, we concluded that the PBPK model is still a valuable tool for converting dietary pesticide exposures to absorbed dose estimates when the model input data are accurate estimates of dietary pesticide exposures.

Temperature effects on hospital admissions for kidney morbidity in Taiwan

OBJECTIVE This study aimed to associate hospital admissions of kidney diseases with extreme temperature and prolonged heat/cold events in 7 regions of Taiwan. METHODS Age-specific (<65 years, 65+years and all ages) hospital admission records of nephritis, nephrotic syndrome, or nephrosis, in the form of electronic insurance reimbursement claims, were retrieved from Taiwans National Health Insurance Research Database during the period of 2000-2008. The area-age-specific relative risk (RR) accounting for 8 days of lag for temperature on hospital admissions of kidney diseases were estimated using distributed lag non-linear models with the Poisson distribution controlling for extreme temperature events, levels of air pollutants (PM(10), O(3), and NO(2)) and potential confounders. RESULTS We observed a V or J-shape association between daily average temperatures and the RR estimates for hospital admissions of kidney diseases in Taiwan. The lowest risk for hospital admissions of kidney diseases was found at around 25 °C, and risk increased as temperatures deviated from 25 °C. The pooled cumulative 8-day RR for all ages of population of the 7 study areas were 1.10 (95% confidence interval (CI): 1.01, 1.19) at 18 °C and 1.45 (95% CI: 1.27, 1.64) at 30 °C. High temperature has more profound influence on hospital admission of kidney diseases than low temperature. Temperature risks for hospital admissions were similar between younger (<65 years) and elderly (65+years) population. This study observed no significant effects of prolonged heat extremes on hospital admissions of kidney diseases. CONCLUSIONS The heat effect for kidney morbidities leading to hospital admission was more significant than that of the cold temperature. This study did not find the age-dependent relative risks for temperature associating with hospital admissions of kidney diseases.

Assessing the association between pesticide exposure and cognitive development in rural Costa Rican children living in organic and conventional coffee farms.

We examined the association between pesticide exposure and cognitive development among rural Costa Rican children in a cross-sectional study. Study participants aged 4-10 years included 17 children whose parents worked in La Amistad organic coffee plantation and 18 Las Mellizas children whose parents worked in their own small conventional coffee farms. Two spot-urine samples were collected from each participant and analyzed for organophosphorus and pyrethroids pesticide metabolites. We administered the computerized Behavioral Assessment and Research System (BARS), a figure-drawing task, and a long-term memory test to evaluate study participants cognitive development. Although urinary pesticide metabolite levels did not vary considerably between these two groups of children, we found that Las Mellizas children performed better in BARS and the figure drawing tests than did La Amistad. The results from the linear mixed-effects models suggested that family socioeconomic status (SES) might be a significant contributor to the variation of the outcomes of the neurobehavioral tests. The effect of pesticide exposure, however, as measured in a snapshot fashion, did not play a significant role to the performance of the cognitive development evaluation. Regardless of the study limitations, needed effort should be devoted to the improvement of the SES on the La Amistad families so that their childrens cognitive development would not be compromised further. Additionally, future studies should focus on addressing the limitations imposed on the snapshot assessment of pesticide exposure and on conducting cognitive development evaluation so the link between childhood pesticide exposure and their cognitive development can be thoroughly investigated.

Concurrent exposures to nonylphenol, bisphenol A, phthalates, and organophosphate pesticides on birth outcomes: A cohort study in Taipei, Taiwan

Prenatal exposure to phenols, phthalates (PAEs), and organophosphate (OP) pesticides may increase the risk of abnormal birth outcomes. However, many previous studies have examined exposure to a limited number of chemical classes or exposure profiles limited to a specific stage of pregnancy. This study aims to characterize the concurrent exposure scenario throughout pregnancy by simultaneously monitoring internal doses of several endocrine-disrupting compounds (EDCs), including 2 phenols (nonylphenol (NP) and bisphenol A (BPA)), 9 PAEs, and 6 OP pesticide metabolites and to assess the relationships between concurrent exposure to EDCs and infant birth weight, length, and head and chest circumference. One hundred and sixty two women provided three spot urine samples at approximately 11 and 26weeks gestation and at delivery. We applied multivariable linear regression and ridge regression models to estimate the effects of separate and correlated exposures. Multivariable linear regression models revealed that women with short birth-length infants had significantly higher urinary second-trimester NP levels (50th percentile, 5.03μg/g creatinine) (β=-0.47cm; 95% CI=-0.93 to -0.01). Similarly significant relationships were observed between second-trimester mono-methyl phthalate (MMP) exposure and short birth length, second-trimester ΣPAEs and short birth length, second-trimester ΣPAEs exposure and reduced head and chest circumference, second-trimester diethylphosphate (DEP) exposure and reduced birth weight and length, and second-trimester ΣDEPs exposure and short birth length. Women with urinary BPA above the 75th percentile or ΣPAEs levels above the 50th percentile in the third trimester had infants with significantly reduced head circumference. These observations suggest that the second trimester may be the critical stage of susceptibility for fetal development. In ridge regression models, for which women with fewer measures for exposure to NP, BPA, MMP, ΣPAEs, DEP and ΣDEPs simultaneously were available, no relationships were found with infant size at birth. Additional studies with larger sample sizes are warranted.

Distributions of neonicotinoid insecticides in the Commonwealth of Massachusetts: a temporal and spatial variation analysis for pollen and honey samples

Environmental context Neonicotinoids are a group of widely used insecticides that have been implicated in the deterioration of honeybee health and the declining number of honeybee colonies worldwide. We wanted to find out whether neonicotinoids are commonly present in pollen and honey, which are the main food sources for bees. The results show that neonicotinoids are ubiquitous in the environment where bees foraged, and therefore could pose risks to honeybee health. Abstract It is known that honeybees are exposed to a wide variety of pesticides, including systemic neonicotinoids, through different media. Pollen might be a better matrix for assessing exposure to neonicotinoid not only because it is the protein source for bees, but also because pollen collected from foraging bees could help to establish the field-realistic levels of neonicotinoids. In this study, we aimed to assess temporal and spatial variations of neonicotinoids in pollen collected across the Commonwealth of Massachusetts. Monthly pollen samples and a honey sample were collected between April and August 2013 from 62 volunteered hives and analysed for eight neonicotinoids. We utilised the relative potency factor (RPF) method to integrate individual neonicotinoids into a single measurement of imidaclopridRPF. We then analysed the spatial and temporal variations of imidaclopridRPF in pollen using the response profile analysis. Overall, 73% of pollen and 72% of honey samples contained at least one detectable neonicotinoid. We found that 49, 20 and 4% of pollen samples contained one, two and three neonicotinoids respectively. In honey, we detected that 57 and 15% of samples contained one and two neonicotinoids respectively. Neonicotinoids as a group, or imidacloprid, in pollen exhibited no significant temporal or spatial variation, however, we found statistically significant spatial–temporal interaction differences of imidaclopridRPF concentrations. Considering the ubiquitous of neonicotinoids in the environment and their effects on bees at the sub-lethal levels, it is prudent to identify ways to minimise the uses of neonicotinoids in order to reduce the risk of neonicotinoid exposure to honeybees.