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ABSTRACT: Although the production and use of some persistent organic pollutants (POPs) have been banned or highly restricted, human exposure remains a subject of investigation due to their environmental persistence. Physiological changes during pregnancy may affect the disposition of POPs in the mother's body, and thus fetal exposure. Changes in serum concentrations of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) across pregnancy trimesters, and trans-placental transfer to the fetus were investigated. Seventy-nine pregnant women in Trujillo, Peru were recruited in the first trimester of pregnancy, and provided blood samples for the analysis of 35 PCB congeners, 9 OCPs, and 11 polybrominated biphenyl diethers (PBDEs). Subsequently, maternal blood samples were collected in the second (n=64) and third trimesters (n=59), and cord blood samples (n=50) were collected at delivery. There were statistically significant changes across trimesters (p<0.05) for both fresh weight (increase) and lipid adjusted concentrations (decrease) of hexachlorobenzene (HCB), 2,2-Bis(4-chlorophenyl)-1,1-dichloroethene (p,p'-DDE), PCB-74, 118, 138-158, 153, 170, 180 and 194. Fresh weight concentrations of these POPs increased from first to third trimester by 10-28%. On the other hand lipid adjusted concentrations decreased from first to third trimester by 16-28%. Serum lipids increased from first to third trimester by 53% indicating the dilution of the POPs in the lipids. Concentrations of 2,2-Bis(4-chlorophenyl)-1,1,1-trichloroethane (p,p'-DDT), its metabolite p,p'-DDE, PCB-118, 138-158, 153, 170 and 180 above their limits of detection were measured in >60% of cord serum samples. Intra-individual correlations in maternal serum concentrations were high for most of the POPs (ρ=0.62-0.99; p<0.05) while correlations between maternal and cord serum concentrations were also high (ρ=0.68-0.99; p<0.05). Results indicate that the disposition in the body and blood concentrations of POPs may change during pregnancy, and show trans-placental transfer of DDT, DDE and PCBs.
Chemosphere 02/2013; · 3.21 Impact Factor
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ABSTRACT: Women and children in developing countries are often exposed to high levels of air pollution including polycyclic aromatic hydrocarbons (PAHs), which may negatively impact their health, due to household combustion of biomass fuel for cooking and heating. We compared creatinine adjusted hydroxy-PAH (OH-PAH) concentrations in pregnant women in Trujillo, Peru who cook with wood to levels measured in those who cook with kerosene, liquefied petroleum gas or a combination of fuels. Seventy-nine women were recruited for the study between May and July 2004 in the first trimester of their pregnancy. Urine samples were collected from the subjects in the first, second and third trimesters for OH-PAH analyses. The concentrations of the OH-PAHs were compared across the type of fuel used for cooking and pregnancy trimesters. The relationships between OH-PAHs levels in the first trimester and concurrently measured personal exposures to PM(2.5), carbon monoxide and nitrogen dioxide together with their indoor and outdoor air concentrations were also investigated. Women cooking with wood or kerosene had the highest creatinine adjusted OH-PAH concentrations compared with those using gas, coal briquette or a combination of fuels. Concentrations of creatinine adjusted 2-hydroxy-fluorene, 3-hydroxy-fluorene, 1-hydroxy-fluorene, 2-hydroxy-phenanthrene and 4-hydroxy-phenanthrene were significantly higher (p<0.05) in women who used wood or kerosene alone compared with women who used liquefied petroleum gas (LPG), coal briquette or a combination of fuels. An increase in the concentrations of creatinine adjusted 9-hydroxy-fluorene, 1-hydroxy-phenanthrene, 2-hydroxy-phenanthrene, 4-hydroxy-phenanthrene and 1-hydroxy-pyrene in the third trimesters was also observed. Weak positive correlation (Spearman correlation coefficient, ρ<0.4; p<0.05) was observed between all first trimester creatinine adjusted OH-PAHs and indoor (kitchen and living room), and personal 48-h TWA PM(2.5). Women who cooked exclusively with wood or kerosene had higher creatinine adjusted OH-PAH levels in their urine samples compared to women who cooked with LPG or coal briquette.
Environment international 01/2013; 53C:1-8. · 4.79 Impact Factor
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Olorunfemi Adetona,
Andreas Sjodin,
Li Zheng,
Lovisa C Romanoff,
Manuel Aguilar-Villalobos, Larry L Needham,
Daniel B Hall,
Antonio Luis,
Brandon E Cassidy,
Christopher D Simpson,
Luke P Naeher
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ABSTRACT: Public transport vehicle drivers, especially in highly polluted or trafficked areas, are exposed to high levels of air pollutants. In this study, we assessed the influence of traffic on levels of hydroxy polycyclic aromatic hydrocarbons (OH-PAHs) in commercial bus drivers in Trujillo, Peru, by measuring the within-shift changes in the urinary whole weight and creatinine-corrected concentrations of the PAH metabolites. We measured personal PM(2.5) as a proxy of exposure to traffic emission. Urine samples were collected daily from two bus drivers and three minivan drivers in Trujillo, pre-, mid-, post-work shift and on days when the drivers were off work (total n = 144). Ten OH-PAH metabolites were measured in the urine samples. Drivers were also monitored for exposure to PM(2.5) (n = 41). Daily work shift (mean = 13.1 ± 1.3 hr) integrated PM(2.5) was measured in the breathing zones of the drivers for an average of 10.5 days per driver. The differences across shift in OH-PAH concentrations were not statistically significant except for urinary 2-hydroxyfluorene (2-FLU) (p = 0.04) and 4-hydroxyphenanthrene (4-PHE) (p = 0.01) and creatinine-corrected 4-hydroxyphenanthrene (p = 0.01). Correlation between pairs of hydroxy-PAHs (ρ = 0.50 to 0.93) were highest for mid-shift samples. Concentrations of PM(2.5) (geometric mean = 64 μg/m(3); 95% confidence limits = 52 μg/m(3), 78 μg/m(3)) is similar to those measured in many other studies of traffic exposure. There was significant change across work shift for concentrations of only two of the OH-PAHs (2-FLU and 4-PHE). Results indicate that the drivers may have had limited time for clearance of PAH exposure from the body between work shifts. Comparisons of the concentrations of creatinine-corrected hydroxy-PAH to those reported in other studies indicate that exposure of public transport drivers to PAH could be similar. By following the subjects over multiple days, this study gives an indication of appropriate exposure situations for the use of hydroxy-PAHs and will be beneficial in designing future occupational studies of PAH exposure.
Journal of Occupational and Environmental Hygiene 04/2012; 9(4):217-29. · 1.19 Impact Factor
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ABSTRACT: 2,3,7,8-Tetrachlorodibenzo-para-dioxin (TCDD), a widespread environmental contaminant, disrupts multiple endocrine pathways. The International Agency for Research on Cancer classified TCDD as a known human carcinogen, based on predominantly male occupational studies of increased mortality from all cancers combined.
After a chemical explosion on 10 July 1976 in Seveso, Italy, residents experienced some of the highest levels of TCDD exposure in a human population. In 1996, we initiated the Seveso Women's Health Study (SWHS), a retrospective cohort study of the reproductive health of the women. We previously reported a significant increased risk for breast cancer and a nonsignificant increased risk for all cancers combined with individual serum TCDD, but the cohort averaged only 40 years of age in 1996. Herein we report results for risk of cancer from a subsequent follow-up of the cohort in 2008.
In 1996, we enrolled 981 women who were 0-40 years of age in 1976, lived in the most contaminated areas, and had archived sera collected near the explosion. Individual TCDD concentration was measured in archived serum by high-resolution mass spectrometry. A total of 833 women participated in the 2008 follow-up study. We examined the relation of serum TCDD with cancer incidence using Cox proportional hazards models.
In total, 66 (6.7%) women had been diagnosed with cancer. The adjusted hazard ratio (HR) associated with a 10-fold increase in serum TCDD for all cancers combined was significantly increased [adjusted HR = 1.80; 95% confidence interval (CI): 1.29, 2.52]. For breast cancer, the HR was increased, but not significantly (adjusted HR = 1.44; 95% CI: 0.89, 2.33).
Individual serum TCDD is significantly positively related with all cancer incidence in the SWHS cohort, more than 30 years later. This all-female study adds to the epidemiologic evidence that TCDD is a multisite carcinogen.
Environmental Health Perspectives 08/2011; 119(12):1700-5. · 7.04 Impact Factor
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Dana Boyd Barr,
Lee-Yang Wong,
Roberto Bravo,
Gayanga Weerasekera,
Martins Odetokun,
Paula Restrepo,
Do-Gyun Kim,
Carolina Fernandez,
Ralph D Whitehead,
Jose Perez,
Maribel Gallegos,
Bryan L Williams, Larry L Needham
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ABSTRACT: Organophosphorus (OP) insecticides were among the first pesticides that EPA reevaluated as part of the Food Quality Protection Act of 1996. Our goal was to assess exposure to OP insecticides in the U.S. general population over a six-year period. We analyzed 7,456 urine samples collected as part of three two-year cycles of the National Health and Nutrition Examination Survey (NHANES) from 1999-2004. We measured six dialkylphosphate metabolites of OP pesticides to assess OP pesticide exposure. In NHANES 2003-2004, dimethylthiophosphate was detected most frequently with median and 95th percentile concentrations of 2.03 and 35.3 μg/L, respectively. Adolescents were two to three times more likely to have diethylphosphate concentrations above the 95th percentile estimate of 15.5 μg/L than adults and senior adults. Conversely, for dimethyldithiophosphate, senior adults were 3.8 times and 1.8 times more likely to be above the 95th percentile than adults and adolescents, respectively, while adults were 2.1 times more likely to be above the 95th percentile than the adolescents. Our data indicate that the most vulnerable segments of our population-children and older adults-have higher exposures to OP pesticides than other population segments. However, according to DAP urinary metabolite data, exposures to OP pesticides have declined during the last six years at both the median and 95th percentile levels.
International Journal of Environmental Research and Public Health 08/2011; 8(8):3063-98. · 1.61 Impact Factor
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Susan A Korrick,
Mary M Lee,
Paige L Williams,
Oleg Sergeyev,
Jane S Burns,
Donald G Patterson,
Wayman E Turner, Larry L Needham,
Larisa Altshul,
Boris Revich,
Russ Hauser
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ABSTRACT: Animal data demonstrate associations of dioxin, furan, and polychlorinated biphenyl (PCB) exposures with altered male gonadal maturation. It is unclear whether these associations apply to human populations.
We investigated the association of dioxins, furans, PCBs, and corresponding toxic equivalent (TEQ) concentrations with pubertal onset among boys in a dioxin-contaminated region.
Between 2003 and 2005, 499 boys 8-9 years of age were enrolled in a longitudinal study in Chapaevsk, Russia. Pubertal onset [stage 2 or higher for genitalia (G2+) or testicular volume (TV) > 3 mL] was assessed annually between ages 8 and 12 years. Serum levels at enrollment were analyzed by the Centers for Disease Control and Prevention, Atlanta, Georgia, USA. We used Cox proportional hazards models to assess age at pubertal onset as a function of exposure adjusted for potential confounders. We conducted sensitivity analyses excluding boys with pubertal onset at enrollment.
The median (range) total serum TEQ concentration was 21 (4-175) pg/g lipid, approximately three times higher than values in European children. At enrollment, boys were generally healthy and normal weight (mean body mass index, 15.9 kg/m2), with 30% having entered puberty by G2+ and 14% by TV criteria. Higher dioxin TEQs were associated with later pubertal onset by TV (hazard ratio = 0.68, 95% confidence interval, 0.49-0.95 for the highest compared with the lowest quartile). Similar associations were observed for 2,3,7,8-tetrachlorodibenzo-p-dioxin and dioxin concentrations for TV but not G2+. Results were robust to sensitivity analyses.
Findings support an association of higher peripubertal serum dioxin TEQs and concentrations with later male pubertal onset reflected in delayed testicular maturation.
Environmental Health Perspectives 04/2011; 119(9):1339-44. · 7.04 Impact Factor
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ABSTRACT: Passage of environmental chemicals across the placenta has important toxicological consequences, as well as for choosing samples for analysis and for interpreting the results. To obtain systematic data, we collected in 2000 maternal and cord blood, cord tissue, placenta, and milk in connection with births in the Faroe Islands, where exposures to marine contaminants is increased. In 15 sample sets, we measured a total of 87 environmental chemicals, almost all of which were detected both in maternal and fetal tissues. The maternal serum lipid-based concentrations of organohalogen compounds averaged 1.7 times those of cord serum, 2.8 times those of cord tissue and placenta, and 0.7 those of milk. For organohalogen compounds detectable in all matrices, a high degree of correlation between concentrations in maternal serum and the other tissues investigated was generally observed (r(2) > 0.5). Greater degree of chlorination resulted in lower transfer from maternal serum into milk. Concentrations of pentachlorbenzene, γ-hexachlorocyclohexane, and several polychlorinated biphenyl congeners with low chlorination were higher in fetal samples and showed poor correlation with maternal levels. Perfluorinated compounds occurred in lower concentrations in cord serum than in maternal serum. Cadmium, lead, mercury, and selenium were all detected in fetal samples, but only mercury showed close correlations among concentrations in different matrices. Although the environmental chemicals examined pass through the placenta and are excreted into milk, partitions between maternal and fetal samples are not uniform.
Environmental Science & Technology 02/2011; 45(3):1121-6. · 4.80 Impact Factor
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ABSTRACT: High-molecular-weight phthalates, such as diisononyl phthalate (DINP) and diisodecyl phthalate (DIDP), are used primarily as polyvinyl chloride plasticizers.Objectives: We assessed exposure to DINP and DIDP in a representative sample of persons ≥ 6 years of age in the U.S. general population from the 2005-2006 National Health and Nutrition Examination Survey (NHANES).
We analyzed 2,548 urine samples by using online solid-phase extraction coupled to isotope dilution high-performance liquid chromatography-tandem mass spectrometry.
We detected monocarboxyisooctyl phthalate (MCOP), a metabolite of DINP, and monocarboxyisononyl phthalate (MCNP), a metabolite of DIDP, in 95.2% and 89.9% of the samples, respectively. We detected monoisononyl phthalate (MNP), a minor metabolite of DINP, much less frequently (12.9%) and at concentration ranges (> 0.8 µg/L-148.1 µg/L) much lower than MCOP (> 0.7 µg/L- 4,961 µg/L). Adjusted geometric mean concentrations of MCOP and MCNP were significantly higher (p < 0.01) among children than among adolescents and adults.
The general U.S. population, including children, was exposed to DINP and DIDP. In previous NHANES cycles, the occurrence of human exposure to DINP by using MNP as the sole urinary biomarker has been underestimated, thus illustrating the importance of selecting the most adequate biomarkers for exposure assessment.
Environmental Health Perspectives 01/2011; 119(1):50-5. · 7.04 Impact Factor
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Jane S Burns,
Paige L Williams,
Oleg Sergeyev,
Susan Korrick,
Mary M Lee,
Boris Revich,
Larisa Altshul,
Julie T Del Prato,
Olivier Humblet,
Donald G Patterson,
Wayman E Turner, Larry L Needham,
Mikhail Starovoytov,
Russ Hauser
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ABSTRACT: We evaluated the associations of serum dioxins and polychlorinated biphenyls (PCBs) with longitudinally assessed growth measurements among peripubertal Russian boys.
A total of 499 boys from Chapaevsk, Russia, aged 8 to 9 years were enrolled in the study from 2003 to 2005 and were followed prospectively for 3 years. Blood samples were collected and physical examinations were conducted at entry and repeated at annual study visits. Multivariate mixed-effects regression models for repeated measures were used to examine the associations of serum dioxins and PCBs with longitudinal measurements of BMI, height, and height velocity.
Serum dioxin (total 2005 toxic equivalency [TEQ] median: 21.1 pg/g lipid) and PCBs (median sum of PCBs: 250 ng/g lipid) were measured in 468 boys. At study entry and during 3 years of follow-up, >50% of the boys had age-adjusted BMI and height z scores within 1 SD of World Health Organization-standardized mean values for age. Boys in the highest exposure quintile of the sum of dioxin and PCB concentrations and total TEQs had a significant decrease in mean BMI z scores of 0.67 for dioxins and TEQs and 1.04 for PCBs, compared with boys in the lowest exposure quintile. Comparison of the highest versus the lowest quintile revealed that higher serum PCB concentrations were associated with significantly lower height z scores (mean z-score decrease: 0.41) and height velocity (mean decrease: 0.19 cm/year) after 3 years of follow-up.
Our findings suggest that exposures to dioxins and PCBs are associated with reduced growth during the peripubertal period and may compromise adult body mass, stature, and health.
PEDIATRICS 01/2011; 127(1):e59-68. · 4.47 Impact Factor
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ABSTRACT: Concern is mounting that children from disadvantaged, low-income neighborhoods are likely to be both more exposed to chemical hazards and more susceptible to related adverse health effects. This article reports measurements of >75 individual biomarkers spanning 7 chemical/pollutant classes in blood and urine from more than 100 children living in a socioeconomically disadvantaged and ethnically diverse area of south Minneapolis, MN. Results indicate that a significant proportion of children in the study were at the high end of the exposure distribution compared to national reference ranges for a variety of environmental chemicals and/or their metabolites, including phthalates, organochlorine pesticides, organophosphate pesticides, metals, polychlorinated biphenyls, and volatile organic compounds. In addition, levels of cotinine in urine indicate that more than half the children were regularly exposed to environmental tobacco smoke, with the upper 10th percentile exposed to relatively high concentrations.
Journal of Toxicology and Environmental Health Part A 01/2011; 74(14):927-42. · 1.83 Impact Factor
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ABSTRACT: There is emerging evidence that background exposure to persistent organic pollutants (POPs) are important in the development of conditions predisposing to diabetes as well as of type 2 diabetes itself. We recently reported that low dose POPs predicted incident type 2 diabetes in a nested case-control study. The current study examined if low dose POPs predicted future adiposity, dyslipidemia, and insulin resistance among controls without diabetes in that study.
The 90 controls were diabetes-free during 20 years follow-up. They were a stratified random sample, enriched with overweight and obese persons. POPs measured in 1987-88 (year 2) sera included 8 organochlorine (OC) pesticides, 22 polychlorinated biphenyls (PCBs), and 1 polybrominated biphenyl (PBB). Body mass index (BMI), triglycerides, HDL-cholesterol, LDL-cholesterol, and homeostasis model assessment value for insulin resistance (HOMA-IR) were study outcomes at 2005-06 (year 20). The evolution of study outcomes during 18 years by categories of serum concentrations of POPs at year 2 was evaluated by adjusting for the baseline values of outcomes plus potential confounders. Parallel to prediction of type 2 diabetes, many statistically significant associations of POPs with dysmetabolic conditions appeared at low dose, forming inverted U-shaped dose-response relations. Among OC pesticides, p,p'-DDE most consistently predicted higher BMI, triglycerides, and HOMA-IR and lower HDL-cholesterol at year 20 after adjusting for baseline values. Oxychlordane, trans-nonachlor, and hexachlorobenzene also significantly predicted higher triglycerides. Persistent PCBs with ≥7 chlorides predicted higher BMI, triglycerides, and HOMA-IR and lower HDL-cholesterol at year 20 with similar dose-response curves.
Simultaneous exposure to various POPs in the general population may contribute to development of obesity, dyslipidemia, and insulin resistance, common precursors of type 2 diabetes and cardiovascular diseases. Although obesity is a primary cause of these metabolic abnormalities, POPs exposure may contribute to excess adiposity and other features of dysmetabolism.
PLoS ONE 01/2011; 6(1):e15977. · 4.09 Impact Factor
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ABSTRACT: Phthalates are metabolized and eliminated in urine within hours after exposure. Several reports suggest that concentrations of phthalate metabolites in a spot urine sample can provide a reliable estimation of exposure to phthalates for up to several months.
We examined inter- and intraperson and inter- and intraday variability in the concentrations of monoethyl phthalate (MEP), the major metabolite of diethyl phthalate, commonly used in personal care products, and mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), a metabolite of di(2-ethylhexyl) phthalate (DEHP), a polyvinyl chloride plasticizer of which diet is the principal exposure source, among eight adults who collected all urine voids (average, 7.6 samples/person/day) for 1 week.
We analyzed the urine samples using online solid-phase extraction coupled to isotope dilution-high-performance liquid chromatography-tandem mass spectrometry.
Regardless of the type of void (spot, first morning, 24-hr collection), for MEP, interperson variability in concentrations accounted for > 75% of the total variance. By contrast, for MEHHP, within-person variability was the main contributor (69-83%) of the total variance. Furthermore, we observed considerable intraday variability in the concentrations of spot samples for MEHHP (51%) and MEP (21%).
MEP and MEHHP urinary concentrations varied considerably during 1 week, but the main contributors to the total variance differed (interday variability, MEHHP; interperson variability, MEP) regardless of the sampling strategy (spot, first morning, 24-hr collection). The nature of the exposure (diet vs. other lifestyle factors) and timing of urine sampling to evaluate exposure to phthalates should be considered. For DEHP and phthalates to which people are mostly exposed through diet, collecting 24-hr voids for only 1 day may not be advantageous compared with multiple spot collections. When collecting multiple spot urine samples, changing the time of collection may provide the most complete approach to assess exposure to diverse phthalates.
Environmental Health Perspectives 12/2010; 118(12):1748-54. · 7.04 Impact Factor
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ABSTRACT: The extensive use of bisphenol A (BPA) in the manufacture of consumer products results in widespread human exposure to the chemical. In the body, BPA undergoes first-pass metabolism to form BPA glucuronide, considered to be a major BPA byproduct. Concentrations of total (free plus conjugated) urinary species of BPA are used to assess human exposure to BPA. However, because BPA can be present in numerous consumer and household products, potential contamination with parent BPA during collection and handling may pose a challenge when measuring BPA in such biological samples as blood or urine. In this study we investigated the in-vitro phase I metabolism of BPA in rat and human liver microsomes by using on-line solid-phase extraction-high-performance liquid chromatography-tandem mass spectrometry to identify phase I metabolites (e.g., BPA oxidation products) that could be used as potential alternative biomarkers of BPA exposure. We unambiguously identified 5-hydroxy BPA (BPA catechol) as an in-vitro oxidative metabolite of BPA, but human microsomes oxidized only about 10% of BPA to BPA catechol. We evaluated the usefulness of BPA catechol as a potential biomarker of human exposure to BPA by measuring total concentrations of BPA catechol and BPA in 20 urine samples. We detected BPA catechol at much lower concentrations and frequency than those of BPA. Furthermore, we found that free BPA catechol was rather unstable in urine, which highlights the importance of sampling techniques to adequate interpretation of biomonitoring data. Together, these findings suggest that BPA catechol may not be a suitable biomarker of environmental exposure to BPA, but could be used to confirm BPA exposure in special populations or in situations when urine specimens were potentially contaminated with BPA.
Analytical and Bioanalytical Chemistry 11/2010; 399(3):1071-9. · 3.78 Impact Factor
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ABSTRACT: Maternal smoking during pregnancy is associated with increased risk of childhood overweight body mass index (BMI). Less is known about the association between prenatal secondhand tobacco smoke (SHS) exposure and childhood BMI. We followed 292 mother-child dyads from early pregnancy to 3 years of age. Prenatal tobacco smoke exposure during pregnancy was quantified using self-report and serum cotinine biomarkers. We used linear mixed models to estimate the association between tobacco smoke exposure and BMI at birth, 4 weeks, and 1, 2 and 3 years. During pregnancy, 15% of women reported SHS exposure and 12% reported active smoking, but 51% of women had cotinine levels consistent with SHS exposure and 10% had cotinine concentrations indicative of active smoking. After adjustment for confounders, children born to active smokers (self-report or serum cotinine) had higher BMI at 2 and 3 years of age, compared with unexposed children. Children born to women with prenatal serum cotinine concentrations indicative of SHS exposure had higher BMI at 2 (mean difference [MD] 0.3 [95% confidence interval -0.1, 0.7]) and 3 (MD 0.4 [0, 0.8]) years compared with unexposed children. Using self-reported prenatal exposure resulted in non-differential exposure misclassification of SHS exposures that attenuated the association between SHS exposure and BMI compared with serum cotinine concentrations. These findings suggest active and secondhand prenatal tobacco smoke exposure may be related to an important public health problem in childhood and later life. In addition, accurate quantification of prenatal secondhand tobacco smoke exposures is essential to obtaining valid estimates.
Paediatric and Perinatal Epidemiology 11/2010; 24(6):524-34. · 2.31 Impact Factor
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ABSTRACT: Concern has increased about the resulting health effects of exposure to melamine and its metabolic contaminant, cyanuric acid, after infants in China were fed baby formula milk products contaminated with these compounds. We have developed a selective and sensitive analytical method to quantify the amount of cyanuric acid in human urine. The sample preparation involved extracting free-form cyanuric acid in human urine using anion exchange solid phase extraction. Cyanuric acid was separated from its urinary matrix components on the polymeric strong anion exchange analytical column; the analysis was performed by high performance liquid chromatography-tandem mass spectrometry using negative mode electrospray ionization interface. Quantification was performed using isotope dilution calibration covering the concentration range of 1.00-200ng/mL. The limit of detection was 0.60ng/mL and the relative standard deviations were 2.8-10.5% across the calibration range. The relative recovery of cyanuric acid was 100-104%. Our method is suitable to detect urinary concentrations of cyanuric acid caused by either environmental exposures or emerging poisoning events.
Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 10/2010; 878(28):2916-22. · 2.78 Impact Factor
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ABSTRACT: Di-n-pentyl phthalate (DPP) is used mainly as a plasticizer in nitrocellulose. At high doses, DPP acts as a potent testicular toxicant in rats. We administered a single oral dose of 500 mg kg(-1)bw of DPP to adult female Sprague-Dawley rats (N=9) and collected 24-h urine samples 1d before and 24- and 48-h after DPP was administered to tentatively identify DPP metabolites that could be used as exposure biomarkers. At necropsy, 48 h after dosing, we also collected serum. The metabolites were extracted from urine or serum, resolved with high performance liquid chromatography, and detected by mass spectrometry. Two DPP metabolites, phthalic acid (PA) and mono(3-carboxypropyl) phthalate (MCPP), were identified by using authentic standards, whereas mono-n-pentyl phthalate (MPP), mono(4-oxopentyl) phthalate (MOPP), mono(4-hydroxypentyl) phthalate (MHPP), mono(4-carboxybutyl) phthalate (MCBP), mono(2-carboxyethyl) phthalate (MCEP), and mono-n-pentenyl phthalate (MPeP) were identified based on their full scan mass spectrometric fragmentation pattern. The ω-1 oxidation product, MHPP, was the predominant urinary metabolite of DPP. The median urinary concentrations (μg mL(-1)) of the metabolites in the first 24h urine collection after DPP administration were 993 (MHPP), 168 (MCBP), 0.2 (MCEP), 222 (MPP), 47 (MOPP), 26 (PA), 16 (MPeP), and 9 (MCPP); the concentrations of metabolites in the second 24 h urine collection after DPP administration were significantly lower than in the first collection. We identified some urinary metabolic products in the serum, but at much lower levels than in urine. Because of the similarities in metabolism of phthalates between rats and humans, based on our results and the fact that MHPP can only be formed from the metabolism of DPP, MHPP would be the most adequate DPP exposure biomarker for human exposure assessment. Nonetheless, based on the urinary levels of MHPP, our preliminary data suggest that human exposure to DPP in the United States is rather limited.
Chemosphere 10/2010; 82(3):431-6. · 3.21 Impact Factor
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ABSTRACT: Perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid, two of the most widely studied polyfluoroalkyl chemicals (PFCs), can cross the placenta. Therefore, data on the exposure to PFCs of the very young are needed to evaluate the potential health effects associated with such exposure. Human serum, especially serum collected from pregnant women and cord serum, may contain endogenous components that can interfere in the separation by high performance liquid chromatography (HPLC) of PFOS and another PFC of interest, perfluorohexane sulfonic acid (PFHxS), from other serum biomolecules. The presence of such interferences may prevent the adequate quantification of PFOS and PFHxS in cord serum or serum collected from pregnant women, and potentially hinder the assessment of gestational exposure to these important PFCs using biomonitoring. We have modified our on-line solid phase extraction-HPLC-isotope dilution-tandem mass spectrometry analytical method for measuring PFCs in serum and developed an approach that allows for the elimination of these potential interferences without compromising analytical sensitivity and throughput. The combination of acetonitrile as the HPLC mobile phase organic solvent and a Betasil C8 HPLC column provided the best separation of PFOS and PFHxS from interferent peaks. In addition to eliminating these interferences, the acetonitrile method has a shorter runtime and is more sensitive for most PFCs (limits of detection were 0.1 ng/mL except for PFOS (0.2 ng/mL)) than our previous method that used methanol for the HPLC separation. The present method should improve the precise and selective analysis of maternal and cord serum for PFCs.
Journal of chromatography. A 10/2010; 1218(15):2133-7. · 4.19 Impact Factor
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ABSTRACT: Organophosphorus (OP) pesticides kill by disrupting a targeted pest's brain and nervous systems. But if humans and other animals are sufficiently exposed, OP pesticides can have the same effect on them. We developed a fast and accurate high-performance liquid chromatography-tandem mass spectrometry method for the quantitative measurement of the following six common dialkylphosphate (DAP) metabolites of organophosphorus insecticides: dimethylphosphate (DMP), dimethylthiophosphate (DMTP), dimethyldithiophosphate (DMDTP), diethylphosphate, (DEP), diethylthiophosphate (DETP), and diethyldithiophosphate (DEDTP). The general sample preparation included 96-well plate solid phase extraction using weak anion exchange cartridges. The analytical separation was performed by high-performance liquid chromatography with a HILIC column. Detection involved a triple quadrupole mass spectrometer with an ESI probe in negative ion mode using multiple reaction monitoring. Repeated analyses of urine samples spiked at 150, 90 and 32 ng/mL with the analytes gave relative standard deviations of less than 22%. The extraction efficiency ranged from 40% to 98%. The limits of detection were in the range of 0.04-1.5 ng/mL. The throughput is 1152 samples per week, effectively quadrupling our previous throughput. The method is safe, quick, and sensitive enough to be used in environmental and emergency biological monitoring of occupational and nonoccupational exposure to organophosphates.
Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 10/2010; 878(27):2567-74. · 2.78 Impact Factor
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ABSTRACT: Acephate, methamidophos, o-methoate, and dimethoate are organophosphorus pesticides, and ethylenethiouria and propylenethiourea are two metabolites from the bisdithiocarbamate fungicide family. They are some of the most widely used pesticides and fungicides in agriculture both domestically and abroad. The existing high-performance liquid chromatography (HPLC)-tandem mass spectrometry (MS/MS) method for the measurement of these compounds in human urine was improved by using a 96-well plate format sample preparation; the use of HPLC-MS/MS was comparable with a concentration range of 0.125 to 50 ng/ml. Deuterium-labeled acephate, ethylenethiouria, and methamidophos were used as internal standards. The sample preparation procedure, in the 96-well format with a 0.8-ml urine sample size, uses lyophilization of samples, followed by extraction with dichloromethane. The analytes were chromatographed on a Zorbax SB-C3 (4.6 × 150 mm, 5.0-μm) column with gradient elution by using 0.1% formic acid in aqueous solution (solvent A) and 0.1% formic acid in methanol (solvent B) mobile phase at a flow rate of 1 ml/min. Quantitative analysis was performed by atmospheric pressure chemical ionization source in positive ion mode using multiple-reaction monitoring of the precursor-to-product ion pairs for the analytes on a TSQ Quantum Ultra HPLC-MS/MS. Repeated analyses of urine samples spiked with high (15 ng/ml), medium (5 ng/ml), and low (1 ng/ml) concentrations of the analytes gave relative SDs of <13%. The limits of detection were in the range of 0.004-0.01 ng/ml. The method also has high accuracy, high precision, and excellent extraction recovery. Furthermore, the improved sample preparation method decreased the cost and labor required while effectively doubling the analytic throughput with minimal matrix effect.
Archives of Environmental Contamination and Toxicology 09/2010; 61(1):59-67. · 1.93 Impact Factor
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ABSTRACT: Phthalates are a group of phthalic acid esters which are used as plasticizers and additives. In laboratory animals, several phthalates are known endocrine disruptors. Several studies have described phthalate exposure in the United States and developed countries but little is known about phthalate exposure in the developing world, particularly during pregnancy. To assess exposure to six different phthalates, we measured the concentrations of nine phthalate metabolites in spot urine samples collected during the first, second, and third trimester of pregnancy from a group of 72 women living in Trujillo, Peru. Additionally, women completed questionnaires to provide demographic characteristics. Statistical analysis via linear models was used to evaluate potential differences in the concentrations of phthalate metabolites by trimester, cooking fuel type, socioeconomic status, and education. All metabolites were detected in>40% of samples analyzed, and mono-n-butyl phthalate, mono (2-ethyl-5-carboxypentyl) phthalate, and monoethyl phthalate were found in>90% of samples. Five of nine unadjusted urinary metabolites and four of nine creatinine-adjusted urinary metabolites were significantly lower in this group of pregnant women living in Peru compared to pregnant women in the US general population.
Chemosphere 09/2010; 80(11):1301-7. · 3.21 Impact Factor
