Myrto Petreas

University of California, Berkeley, Berkeley, CA, United States

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Publications (47)133.12 Total impact

  • [show abstract] [hide abstract]
    ABSTRACT: We characterized the variability in concentrations of polychlorinated biphenyls (PCBs) measured in residential dust. Vacuum cleaner samples were collected from 289 homes in the California Childhood Leukemia Study during two sampling rounds from 2001 to 2010 and 15 PCBs were measured by high resolution gas chromatography-mass spectrometry. Median concentrations of high-volume PCBs (i.e., PCBs 28, 52, 101, 105, 118, 138, 153, and 180) ranged from 1.0-5.8 ng per g of dust in the first sampling round and from 0.8-3.4 ng/g in the second sampling round. For each of these eight PCBs, we used a random-effects model to apportion total variation into regional variability (6-11%), intra-regional between-home variability (27-56%), within-home variability over time (18-52%), and within-sample variability (9-16%). In mixed-effects models, differences in PCB concentrations between homes were explained by home age, with older homes having higher PCB levels. Differences in PCB concentrations within homes were explained by decreasing time trends. Estimated half-lives ranged from 5-18 years, indicating that PCBs are removed very slowly from the indoor environment. Our findings suggest that it may be feasible to use residential dust for retrospective assessment of PCB exposures in studies of children's health.
    Environmental Science & Technology 12/2013; · 5.26 Impact Factor
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    ABSTRACT: Prenatal exposures to polybrominated diphenyl ethers (PBDEs) can harm neurodevelopment in humans and animals. In 2003-2004, PentaBDE and OctaBDE were banned in California and phased-out of US production; resulting impacts on human exposures are unknown. We previously reported that median serum concentrations of PBDEs and their metabolites (OH-PBDEs) among second trimester pregnant women recruited from San Francisco General Hospital (2008-2009; n = 25) were the highest among pregnant women worldwide. We recruited another cohort from the same clinic in 2011-2012 (n = 36) and now compare serum concentrations of PBDEs, OH-PBDEs, polychlorinated biphenyl ethers (PCBs) (structurally similar compounds banned in 1979), and OH-PCBs between two demographically similar cohorts. Between 2008-2009 and 2011-2012, adjusted least-squares geometric mean (LSGM) concentrations of ∑PBDEs decreased 65% (95% CI: 18, 130) from 90.0 ng/g lipid (95% CI: 64.7, 125.2) to 54.6 ng/g lipid (95% CI: 39.2, 76.2) (p = 0.004); ∑OH-PBDEs decreased 6-fold (p < 0.0001); and BDE-47, -99, and -100 declined more than BDE-153. There was a modest, nonsignificant (p = 0.13) decline in LSGM concentrations of ∑PCBs and minimal differences in ∑OH-PCBs between 2008-2009 and 2011-2012. PBDE exposures are likely declining due to regulatory action, but the relative stability in PCB exposures suggests PBDE exposures may eventually plateau and persist for decades.
    Environmental Science & Technology 09/2013; · 5.26 Impact Factor
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    ABSTRACT: Concerns about the adverse health effects of ubiquitous flame retardants spurred our interest in the development of a sensitive and reliable analytical method for these toxic compounds in various sample matrices. This study focuses on the investigation of fragmentation pathways and the structures of target ions of thirteen new halogenated flame retardants. In this study, we use gas chromatography (GC)/high-resolution double-focusing sector mass spectrometry to characterize the fragmentation pathways of these new flame retardants. Along with the isotope patterns, accurate mass data were acquired to verify the molecular formula. The fragmentation pathways are classified based on the types of bond dissociations, e.g. σ-bond cleavage, α-bond cleavage and multiple-bond dissociations with a hydrogen shift. The α-bond dissociation occurs among 1,2-bis-(2,4,6-tribromophenoxy)ethane, allyl 2,4,6-tribromophenyl ether (ATE), 2,3-dibromopropyl 2,4,6-tribromophenyl ether (DPTE) and 2-bromoallyl 2,4,6-tribromophenyl ether (BATE). The peak clusters that dominated ATE, BATE and hexachlorocyclopentenyl-dibromocyclooctane (HCDBCO) spectra correspond to two fragments as proved by accurate mass data and isotope patterns. These two fragments are formed as the result of two competing fragmentation pathways of radical loss and hydrogen shift. Fragmentation pathways of the other compounds are complex, involving cleavage of multiple bonds and hydrogen shifts. The accurate-mass-based GC/MS method offers great selectivity and sensitivity for quantitative analysis of the persistent organic pollutants. Thus, elucidation of the structures of the fragments is of prime importance for building an accurate-mass-based isotopic method. In addition, this study is useful for GC/MS/MS method development because multiple reaction monitoring (MRM) transitions of precursor ions and product ions may be easily elucidated based on these fragmentation patterns. Copyright © 2013 John Wiley & Sons, Ltd.
    Rapid Communications in Mass Spectrometry 07/2013; 27(13):1437-49. · 2.51 Impact Factor
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    ABSTRACT: We characterized the sources of variability for polybrominated diphenyl ethers (PBDEs) in residential dust and provided guidance for investigators who plan to use residential dust to assess exposure to PBDEs. We collected repeat dust samples from 292 households in the Northern California Childhood Leukemia Study during two sampling rounds (from 2001 to 2007 and during 2010) using household vacuum cleaners and measured 22 PBDEs using high resolution gas chromatography-high resolution mass spectrometry. Median concentrations for individual PBDEs ranged from <0.1-2500ng per g of dust. For each of eight representative PBDEs, we used a random-effects model to apportion total variance into regional variability (0-11%), intra-regional between-household variability (17-50%), within-household variability over time (38-74%), and within-sample variability (0-23%) and we used a mixed-effects model to identify determinants of PBDE levels. Regional differences in PBDE dust levels were associated with residential characteristics that differed by region, including the presence of furniture with exposed or crumbling foam and the recent installation of carpets in the residence. Intra-regional differences between households were associated with neighborhood urban density, racial and ethnic characteristics, and to a lesser extent, income. For some PBDEs, a decreasing time trend explained a modest fraction of the within-household variability; however, most of the within-household variability was unaccounted for by our mixed-effects models. Our findings indicate that it may be feasible to use residential dust for retrospective assessment of PBDE exposures in studies of children's health (e.g., the Northern California Childhood Leukemia Study).
    Environment international 04/2013; 57-58C:11-24. · 4.79 Impact Factor
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    ABSTRACT: Polybrominated diphenyl ethers (PBDEs) were widely used as flame retardants in the past three decades. These compounds are lipophilic and easily cross the placenta from pregnant woman to fetus. It is not clear whether hydroxylated PBDEs (OH-PBDEs), with greater hydrophilicity, have different concentrations in maternal and cord serum samples. We analyzed PBDEs (BDE-28, -47, -99, -100, -153, -154, -209) and OH-PBDEs (6-OH-BDE-47, 5-OH-BDE-47, 4'-OH-BDE-49, 5'-OH-BDE-99) in 20 pairs of maternal and cord serum samples collected in Cincinnati, OH in 2011. The geometric mean concentration of ƩOH-BDEs (the sum of four OH-PBDEs) was 49.76 pg/ml in cord sera, higher than 32.84 pg/ml in maternal sera. Similarly, cord serum total BDEs had a higher geometric mean than maternal serum (45.51 vs. 32.07 ng/g lipid). Equal or higher levels of total OH-BDEs and total BDEs in cord serum were observed in 85% and 80% of the mother-neonate pairs, respectively. The study suggests fetuses might receive higher OH-PBDE and PBDE exposure than their mothers.
    Environmental Science & Technology 03/2013; · 5.26 Impact Factor
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    ABSTRACT: BACKGROUND: There is interest in using residential dust to estimate human exposure to environmental contaminants. OBJECTIVES: We characterize the sources of variability for polycyclic aromatic hydrocarbons (PAHs) in residential dust and provide guidance for investigators who plan to use residential dust to assess exposure to PAHs. METHODS: We collected repeat dust samples from 293 households in the Northern California Childhood Leukemia Study during two sampling rounds (from 2001-2007 and during 2010) using household vacuum cleaners and measured 12 PAHs using gas chromatography-mass spectrometry. We used a random- and a mixed-effects model for each PAH to apportion observed variance into four components and to identify sources of variability. RESULTS: Median concentrations for individual PAHs ranged from 10-190 ng per g of dust. For each PAH, total variance was apportioned into regional variability (1-9%), intra-regional between-household variability (24-48%), within-household variability over time (41-57%), and within-sample analytical variability (2-33%). Regional differences in PAH dust levels were associated with estimated ambient air concentrations of PAH. Intra-regional differences between households were associated with the residential construction date and the smoking habits of residents. For some PAHs, a decreasing time trend explained a modest fraction of the within-household variability; however, most of the within-household variability was unaccounted for by our mixed-effects models. Within-household differences between sampling rounds were largest when the interval between dust sample collections was at least 6 years in duration. CONCLUSIONS: Our findings indicate that it may be feasible to use residential dust for retrospective assessment of PAH exposures in studies of health effects.
    Environmental Health Perspectives 03/2013; · 7.26 Impact Factor
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    ABSTRACT: Organochlorine pesticides (OCPs) are persistent endocrine disruptors. OCPs cross the placenta; this prenatal exposure has been associated with adverse pregnancy outcomes. We investigated associations between prenatal exposure to OCPs and gestational age and birth weight in 600 infants born between 1960 and 1963. The primary OCP was 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (p,p'-DDT), its primary metabolite, 1,1'-dichloro-2,2'-bis(p-chlorophenyl)ethylene (p,p'-DDE) and the contaminant, 1,1,1-trichloro-2-(p-chlorophenyl)-2-(o-chlorophenyl)-ethane (o,p'-DDT). Regression analysis indicated that for each natural log unit increase in p,p'-DDT, birth weight increased by 274 grams (95% CI 122, 425) when controlling for p,p'-DDE and o,p'-DDT. At a given level of p,p'-DDT exposure, o,p'-DDT and p,p'-DDE were associated with decreased birth weight. p,p'-DDE was negatively associated with length of gestation, controlling for p,p'-DDT and o,p'-DDT. These findings suggest opposing associations between exposure to p,p'-DDT and p,p'-DDE and birth weight. We did not find evidence to support mediation by maternal thyroid hormone status nor that the association differed by sex.
    Reproductive Toxicology 11/2012; · 3.14 Impact Factor
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    ABSTRACT: Ever since the interest in organic environmental contaminants first emerged 50years ago, there has been a need to present discussion of such chemicals and their transformation products using simple abbreviations so as to avoid the repetitive use of long chemical names. As the number of chemicals of concern has increased, the number of abbreviations has also increased dramatically, sometimes resulting in the use of different abbreviations for the same chemical. In this article, we propose abbreviations for flame retardants (FRs) substituted with bromine or chlorine atoms or including a functional group containing phosphorus, i.e. BFRs, CFRs and PFRs, respectively. Due to the large number of halogenated and organophosphorus FRs, it has become increasingly important to develop a strategy for abbreviating the chemical names of FRs. In this paper, a two step procedure is proposed for deriving practical abbreviations (PRABs) for the chemicals discussed. In the first step, structural abbreviations (STABs) are developed using specific STAB criteria based on the FR structure. However, since several of the derived STABs are complicated and long, we propose instead the use of PRABs. These are, commonly, an extract of the most essential part of the STAB, while also considering abbreviations previously used in the literature. We indicate how these can be used to develop an abbreviation that can be generally accepted by scientists and other professionals involved in FR related work. Tables with PRABs and STABs for BFRs, CFRs and PFRs are presented, including CAS (Chemical Abstract Service) numbers, notes of abbreviations that have been used previously, CA (Chemical Abstract) name, common names and trade names, as well as some fundamental physico-chemical constants.
    Environment international 09/2012; 49C:57-82. · 4.79 Impact Factor
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    ABSTRACT: Polychlorinated biphenyls (PCBs), known endocrine disruptors, were banned in 1979 but persist in the environment. Previous studies are inconsistent regarding prenatal exposure to PCBs and pregnancy outcomes. We investigated associations between prenatal exposure to PCBs and gestational length and birth weight. In a sample of 600 infants (born between 1960 and 1963) randomly selected from Child Health and Development Studies participants followed through adolescence we measured 11 PCB congeners in maternal post partum sera (within three days of delivery). Length of gestation was computed from the reported first day of the last menstrual period (LMP) and delivery date. Linear regression was used to estimate associations between PCB exposure and gestational age and birth weight, adjusting for potential confounders. PCBs were grouped according to hypothesized biological action (1b (sum of weak phenobarbital inducers), 2b (sum of limited dioxin activity), and 3 (sum of CYP1A and CYP2b inducers)) or degree of ortho- substitution (mono, di, tri). Secondary analyses examined associations between total PCB exposure and exposure to individual congeners. Each unit increase in mono-ortho substituted PCBs was associated with a 0.30 week decrease (95% confidence interval (CI) -0.59, -0.016), corresponding to a 2.1 (95% CI -4.13, -0.11) day decrease in length of gestation. Similar associations were estimated for di-ortho substituted PCBs, (1.4 day decrease; (95% CI -2.9, 0.1)) and group 3 PCBs (0.84 day decrease; (95% CI -1.8, 0.11). We found similar associations in congener specific analyses and for the sum of congeners. Our study provides new evidence that PCB exposure shortens length of gestation in humans. This may have public health implications for population exposures.
    Environmental Health 07/2012; 11:49. · 2.71 Impact Factor
  • PPTOX III (Prenatal programming and toxicity); 05/2012
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    ABSTRACT: Polybrominated diphenyl ethers (PBDEs) are brominated flame retardants that act as endocrine disruptors, affecting thyroid hormone homeostasis. As a follow-up to a recent study showing high PBDE levels in household cats and linking PBDE levels with cat hyperthyroidism, we measured PBDEs, polychlorinated biphenyls (PCBs), and organochlorinated pesticides (OCPs) in serum samples from 26 California household cats (16 hyperthyroid, 10 controls) using liquid-liquid extraction and high-resolution gas chromatography/high-resolution mass spectrometry. In the present pilot study, we found that PBDE levels in California house cats were extremely high (ΣPBDEs median = 2,904 ng/g lipid; range, 631-22,537 ng/g lipid). This is approximately 50 times higher than levels in California residents (ΣPBDEs geomean = 62 ± 8.9 ng/g lipid, National Health and Nutrition Examination Survey), who have among the highest human levels in the world. Polybrominated diphenyl ethers congener patterns (BDE-99 major congener, BDE-209 significant) differed markedly from patterns found in California residents (BDE-47 major) or wildlife but resembled patterns found in house dust. Polychlorinated biphenyls and OCPs in cats were highly correlated, consistent with a shared dietary source or pathway of exposure, but did not correlate with PBDEs. This suggests a different source or pathway of exposure for PBDEs, which was most likely house dust. The authors found no evidence that linked levels of PBDEs, PCBs, or OCPs with hyperthyroidism. This may be because of the small sample size, competing or confounding risk factors, or complicated causal mechanisms.
    Environmental Toxicology and Chemistry 11/2011; 31(2):301-6. · 2.62 Impact Factor
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    ABSTRACT: Here we report the first measurements of polybrominated diphenyl ethers (PBDE 47, 99, and 153) alongside 11 organochlorine pesticides (OCPs) and 28 polychlorinated biphenyls (PCBs) in the plasma of albatross from breeding colonies distributed across a large spatial east-west gradient in the North Pacific Ocean. North Pacific albatross are wide-ranging, top-level consumers that forage in pelagic regions of the North Pacific Ocean, making them an ideal sentinel species for detection and distribution of marine contaminants. Our work on contaminant burdens in albatross tissue provides information on transport of persistent organic pollutants (POPs) to the remote North Pacific and serves as a proxy for regional environmental quality. We sampled black-footed (Phoebastria nigripes; n = 20) and Laysan albatross (P. immutabilis; n = 19) nesting on Tern Island, Hawaii, USA, and Laysan albatross (n = 16) nesting on Guadalupe Island, Mexico. Our results indicate that North Pacific albatross are highly exposed to both PCBs and OCPs, with levels ranging from 8.8 to 86.9 ng/ml wet weight and 7.4 to 162.3 ng/ml wet weight, respectively. A strong significant gradient exists between Laysan albatross breeding in the Eastern Pacific, having approximately 1.5-fold and 2.5-fold higher levels for PCBs and OCPs, respectively, compared to those from the Central Pacific. Interspecies levels of contaminants within the same breeding site also showed high variation, with Tern black-footed albatross having approximately threefold higher levels of both PCBs and OCPs than Tern Laysan albatross. Surprisingly, while PBDEs are known to travel long distances and bioaccumulate in wildlife of high trophic status, we detected these three PBDE congeners only at trace levels ranging from not detectable (ND) to 0.74 ng/ml wet weight in these albatross.
    Environmental Toxicology and Chemistry 08/2011; 30(11):2562-9. · 2.62 Impact Factor
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    ABSTRACT: Prenatal exposure to polybrominated diphenyl ethers (PBDEs) may disrupt thyroid function and contribute to adverse neurodevelopmental outcomes. We conducted a pilot study to explore the relationship between serum concentrations of lower-brominated PBDEs (BDE-17 to -154), higher-brominated PBDEs (BDE-183 to -209), and hydroxylated PBDE metabolites (OH-PBDEs) with measures of thyroid function in pregnant women. Concentrations of PBDEs, OH-PBDEs, thyroid-stimulating hormone (TSH), total thyroxine (T(4)), and free T(4) were measured in serum samples collected between 2008 and 2009 from 25 second trimester pregnant women in California. Median concentrations of lower-brominated PBDEs and OH-PBDEs were the highest reported to date in pregnant women. Median concentrations of BDE-47 and the sum of lower-brominated PBDEs (ΣPBDE(5)) were 43.1 ng/g lipid and 85.8 ng/g lipid, respectively, and the sum of OH-PBDEs (ΣOH-PBDE(4)) was 0.084 ng/mL. We observed a positive association between the weighted sum of chemicals known to bind to transthyretin (ΣTTR binders) and TSH levels. We also found positive associations between TSH and ΣPBDE(5), ΣOH-PBDE(4), BDE-47, BDE-85, 5-OH-BDE47, and 4'-OH-BDE49, and an inverse association with BDE-207. Relationships with free and total T(4) were weak and inconsistent. Our results indicate that PBDE exposures are elevated in pregnant women in California and suggest a relationship with thyroid function. Further investigation is warranted to characterize the risks of PBDE exposures during pregnancy.
    Environmental Science & Technology 08/2011; 45(18):7896-905. · 5.26 Impact Factor
  • Miaomiao Wang, June-Soo Park, Myrto Petreas
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    ABSTRACT: Serum samples collected from California women at different time periods: 1960s (n = 40), 1980s (n = 30), and 2009 (n = 35) were examined for the presence of 12 perfluorinated compounds (PFCs) using an online SPE-HPLC-MS/MS method. At each time period, perfluorooctane sulfonate (PFOS) was present at the highest concentration, followed by perfluorooctanoic acid (PFOA, except in the 1960s). We found the highest levels of PFOS (median = 42.1 ng/mL) and perfluorohexane sulfonate (PFHxS, median = 1.56 ng/mL) in the 1960s samples, possibly reflecting widespread use of precursor PFCs. PFOS showed a statistically significant drop from the 1960s to the 1980s (28.8 ng/mL ) and to 2009 (9.0 ng/mL ), the latter being in agreement with national data. For PFOA, there was an approximately 10-fold increase in median concentrations from the 1960s (0.27 ng/mL) to the 1980s (2.71 ng/mL), and a slight drop in the 2009 samples (2.08 ng/mL). For longer chain perfluorocarboxylic acids (PFCAs), there was a continuous build-up in serum from the 1960s to 2009. To our knowledge, this is the first study to investigate temporal changes of PFCs over the past 50 years.
    Environmental Science & Technology 08/2011; 45(17):7510-6. · 5.26 Impact Factor
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    ABSTRACT: Organochlorines (OCs) are putative endocrine disruptors and have been associated with developmental deficits in young children. We investigated the associations between prenatal OC exposure, maternal thyroid levels and neurodevelopmental outcomes at age 5 in a sample of 600 mother-child pairs (300 male, 300 female) enrolled at birth into the longitudinal Child Health and Development Studies between 1960-1963. OC levels were measured from post-partum maternal sera. Neurodevelopmental outcomes of the children were assessed at age 5 using the Lincoln-Oseretsky Motor Development Scale (MDS) (mean ¼ 18.33 � 1.89), the Goodenough-Harris Draw-A-Man Test (DMT) (mean ¼ 9.76 � 3.99), and by drawing three Gesell Figures (GF) (40% passed all 3, 31% passed 2, 29% passed one or less). Linear regression analyses were used to model MDS and DMT outcomes, and polychotomous logistic regression was used to model GF results. For MDS, we found sex specific associations between dichlorodiphenyldichloroethylene (DDE), a metabolite of dichlorodiphenyltrichloroethane (DDT) such that for each log unit increase there was an adjusted 1.18 (95% CI -1.91, -0.45) point reduction in score for girls. No associations were found between OCs and MDS in boys. We also found a small association between PCB203 and MDS in girls. No associations were found between any OC and DMT or GF, nor was any mediation via an effect of OCs by maternal thyroid function found. We conclude that few associations were found between exposure to OCs and developmental outcomes at age 5. Further, the data suggest that neurodevelopmental toxins may have different effects on the developing male and female brains.
    3rd Congress of Epidemiology; 06/2011
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    ABSTRACT: Organochlorine (OC) pesticides are persistent endocrine disruptors. In pregnant women, OC pesticides have the capacity to cross the placenta; this prenatal exposure has been associated with adverse pregnancy outcomes, although the findings are inconsistent. We used a sample of 600 infants (300 male, 300 female) drawn from the Child Health and Development Studies prospective cohort study to investigate the relationship between maternal exposure to OC pesticides and birth weight. Linear regression models were used to examine the associations between dichlorodiphenyltrichloroethane (DDT), accounting for the metabolite, dichlorodiphenyldichloroethylene (DDE) and the contaminant, ortho,para’-DDT (o,p’-DDT). We also examined whether the pathway between OC levels in maternal serum and pregnancy outcomes is mediated by maternal thyroid hormone. For each log unit increase in DDT concentration, adjusted birth weight increased by 98.36 grams (95% confidence interval (CI) 13.19, 183.53). When the effects of DDT, DDE and o,p’-DDT were considered jointly, adjusted birth weight increased by 302.48 grams (95% CI 151.41, 453.55), decreased by 191.22 grams (95% CI -332.67, -49.77) and decreased by 73.13 grams (95% CI -153.32, 7.05), respectively. A significant dose-response relationship was observed with increasing tertiles of DDT corresponding to higher adjusted mean birth weights (p < 0.05) and this effect was substantially magnified when o,p’-DDT and DDE were considered concurrently in the model (p < 0.01). We did not find mediation by thyroid disruption. DDT has been associated with increased risks of breast cancer and diabetes, thus, we suggest that increased birth weight may be one mediator of those associations.
    3rd Congress of Epidemiology; 06/2011
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    ABSTRACT: Polychlorinated biphenyls (PCBs) were used in a variety of industrial applications, but although banned in 1979, persist in the environment. PCBs are considered endocrine disruptors. Previous literature is inconsistent regarding exposure to PCBs and pregnancy outcomes. The present study uses a sample of 600 infants (300 male, 300 female) drawn from the Child Health and Development Studies prospective cohort study to investigate the associations between PCBs and gestational length. We evaluated PCBs in groups according to hypothesized biological action (1b (sum of weak phenobarbital inducers), 2b (sum of limited dioxin activity), and 3 (sum of CYP1A and CYP2b inducers)) or degree of ortho- substitution (mono, di, tri) as certain configurations may interfere with thyroid hormone function. In secondary analyses we examined total exposure and individual congeners. For each log unit increase in total PCB concentration, we found a 0.37 week decrease (95% confidence interval (CI) -0.72, 0.015) in length of gestation. We also found decreases in length of gestation for di-ortho substituted PCBs (0.33 week decrease (95% CI -0.68, 0.0076)) and group 3 PCBs (0.35 week decrease (95% CI -0.69, 0.044)). Decreased gestational length was also found for most congeners. The magnitude of decreased gestation was most pronounced comparing the highest tertile of PCB exposure to the lowest tertile of exposure. No mediation by maternal thyroid function was found. We conclude that there is an approximately 2.3 day decrease in gestational length per log unit increase in PCB exposure. While small for any individual, this may have public health implications for population exposures.
    3rd Congress of Epidemiology; 06/2011
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    ABSTRACT: We conducted a case-control study to evaluate the risk of breast cancer associated with adipose concentrations of polybrominated diphenyl ethers (PBDEs) among women undergoing surgical breast biopsies in the San Francisco Bay Area of California (n=78 cases; 56 controls). Adipose tissue was analyzed for the five major congeners of PBDEs. Unconditional logistic regression was used to estimate age- and race-adjusted exposure-specific odds ratios (ORs) and 95% confidence intervals (95% CI). Adipose levels of PBDEs were among the highest ever reported. Adjusted ORs for the highest compared with lowest levels of exposures were as follows: 0.56 (95% CI 0.19-1.68) for BDE-47; 1.19 (95% CI 0.35-4.10) for BDE-99; 0.91 (95% CI 0.33-2.53) for BDE-100; 0.52 (95% CI 0.19-1.39) for BDE-153; 1.67 (95% CI 0.44-6.29) for BDE-154; 2.04 (95% CI 0.45-9.20) for total BDEs. These results provide no evidence of an association between PBDE adipose concentrations measured at or near the time of diagnosis and breast cancer risk. Our study was limited by a small sample size. Given the high levels of PBDEs found in this population of California women, future studies are warranted. Such studies would benefit from a larger sample size, a more representative control series, and/or a prospective design.
    Breast Cancer Research and Treatment 04/2011; 129(2):505-11. · 4.47 Impact Factor
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    ABSTRACT: Conserving irreplaceable, archived serum samples may sometimes conflict with the objective of minimizing measurement error due to laboratory effects. We sought to determine whether we could successfully combine assay results for DDT-related compounds and polychlorinated biphenyls (PCBs) in serum from the same birth cohort obtained from different laboratories over time. Using the Child Health and Development Studies (CHDS) serum archive, we compared variability for assays of a quality control pool to variability for assays of subject serum. The quality control pool was created from native archived serum samples that were pooled, then aliquoted, blinded and inserted pair-wise into assay batches along with the subject serum for 5 studies using CHDS samples conducted over a 13year period by three different laboratories. We found that the variability between laboratory and over time within laboratory was small relative to inter-individual variability for p,p'-DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane), p,p'-DDE (1,1'-dichloro-2,2'-bis(p-chlorophenyl)ethylene) and o,p'-DDT (1,1,1-trichloro-2-(p-chlorophenyl)-2-(o-chlorophenyl)-ethane). Results were also consistent for most PCB congeners which were detectable in 85% or more of samples. Our results suggest that it is possible to combine assays for DDT and PCB congeners measured at positive levels as they are accumulated for cohort subjects without risking meaningful misclassification due to variation stemming from laboratory or time period. This has significant implications for future study costs, conservation of irreplaceable archived samples and for leveraging past investments for future research. For PCB congeners with very low levels, findings caution against pooling of assays without further exploration.
    Environment international 02/2011; 37(4):709-14. · 4.79 Impact Factor

Publication Stats

574 Citations
133.12 Total Impact Points

Institutions

  • 2004–2013
    • University of California, Berkeley
      • School of Public Health
      Berkeley, CA, United States
  • 2012
    • Columbia University
      • Department of Epidemiology
      New York City, NY, United States
  • 2003–2012
    • California Environmental Protection Agency (Cal/EPA)
      • Department of Toxic Substances Control
      Sacramento, California, United States
  • 2011
    • United States Environmental Protection Agency
      Cincinnati, Ohio, United States
    • Cancer Prevention Institute of California
      Fremont, California, United States
  • 2004–2010
    • State of California
      California City, California, United States
  • 2008
    • University of the Aegean
      Kastro, North Aegean, Greece
  • 2007
    • University of Maine
      Orono, Minnesota, United States