Dana Boyd Barr

Variability and Predictors of Urinary Bisphenol A Concentrations during Pregnancy

Background Prenatal bisphenol A (BPA) exposure may be associated with developmental toxicity, but few studies have examined the variability and predictors of urinary BPA concentrations during pregnancy. Objective Our goal was to estimate the variability and predictors of serial urinary BPA concentrations taken during pregnancy. Methods We measured BPA concentrations during pregnancy and at birth in three spot urine samples from 389 women. We calculated the intraclass correlation coefficient (ICC) to assess BPA variability and estimated associations between log10-transformed urinary BPA concentrations and demographic, occupational, dietary, and environmental factors, using mixed models. Results Geometric mean (GM) creatinine-standardized concentrations (micrograms per gram) were 1.7 (16 weeks), 2.0 (26 weeks), and 2.0 (birth). Creatinine-standardized BPA concentrations exhibited low reproducibility (ICC = 0.11). By occupation, cashiers had the highest BPA concentrations (GM: 2.8 μg/g). Consuming canned vegetables at least once a day was associated with higher BPA concentrations (GM = 2.3 μg/g) compared with those consuming no canned vegetables (GM = 1.6 μg/g). BPA concentrations did not vary by consumption of fresh fruits and vegetables, canned fruit, or store-bought fresh and frozen fish. Urinary high-molecular-weight phthalate and serum tobacco smoke metabolite concentrations were positively associated with BPA concentrations. Conclusions These results suggest numerous sources of BPA exposure during pregnancy. Etiological studies may need to measure urinary BPA concentrations more than once during pregnancy and adjust for phthalates and tobacco smoke exposures.

Validation of a new biomarker of fetal exposure to alcohol

OBJECTIVEnTo test the sensitivity and specificity of fatty acid ethyl esters (FAEEs) extracted from meconium to identify alcohol-using pregnant women with a sensitive and specific methodology, gas chromatography-tandem mass spectroscopy (GC/MS/MS). Study design Twenty-seven samples of meconium were obtained from infants from the mixed race community in Cape Town, South Africa, who were enrolled in a longitudinal neurobehavioral study. Maternal alcohol use was reported prospectively during pregnancy. FAEEs were isolated from meconium and quantitated by GC/MS/MS.nnnRESULTSnEthyl oleate was the FAEE that correlated most strongly with maternal self-reported drinking, especially with the average ounces of absolute alcohol ingested per drinking day. Ethyl oleate was most strongly related to drinking in the second and third trimesters (Pearson r=.55 and.40, respectively). At a threshold of 1.5 average ounces of absolute alcohol ingested per drinking day, the area under the receiving operator characteristic curve was.92 (95% confidence interval, 0.74-0.97). Using a cut-off value of 32 ng/g, sensitivity was 84.2% and specificity was 83.3%.nnnCONCLUSIONSnEthyl oleate concentration in meconium assayed by GC/MS/MS provides a highly sensitive and specific indicator of maternal alcohol use during pregnancy.

Designing prospective cohort studies for assessing reproductive and developmental toxicity during sensitive windows of human reproduction and development--the LIFE Study.

The relationship between the environment and human fecundity and fertility remains virtually unstudied from a couple-based perspective in which longitudinal exposure data and biospecimens are captured across sensitive windows. In response, we completed the LIFE Study with methodology that intended to empirically evaluate a priori purported methodological challenges: implementation of population-based sampling frameworks suitable for recruiting couples planning pregnancy; obtaining environmental data across sensitive windows of reproduction and development; home-based biospecimen collection; and development of a data management system for hierarchical exposome data. We used two sampling frameworks (i.e., fish/wildlife licence registry and a direct marketing database) for 16 targeted counties with presumed environmental exposures to persistent organochlorine chemicals to recruit 501 couples planning pregnancies for prospective longitudinal follow-up while trying to conceive and throughout pregnancy. Enrolment rates varied from <1% of the targeted population (n =u2003424,423) to 42% of eligible couples who were successfully screened; 84% of the targeted population could not be reached, while 36% refused screening. Among enrolled couples, ∼ 85% completed daily journals while trying; 82% of pregnant women completed daily early pregnancy journals, and 80% completed monthly pregnancy journals. All couples provided baseline blood/urine samples; 94% of men provided one or more semen samples and 98% of women provided one or more saliva samples. Women successfully used urinary fertility monitors for identifying ovulation and home pregnancy test kits. Couples can be recruited for preconception cohorts and will comply with intensive data collection across sensitive windows. However, appropriately sized sampling frameworks are critical, given the small percentage of couples contacted found eligible and reportedly planning pregnancy at any point in time.

Neurodevelopmental effects in children associated with exposure to organophosphate pesticides: A systematic review

Many studies have investigated the neurodevelopmental effects of prenatal and early childhood exposures to organophosphate (OP) pesticides among children, but they have not been collectively evaluated. The aim of the present article is to synthesize reported evidence over the last decade on OP exposure and neurodevelopmental effects in children. The Data Sources were PubMed, Web of Science, EBSCO, SciVerse Scopus, SpringerLink, SciELO and DOAJ. The eligibility criteria considered were studies assessing exposure to OP pesticides and neurodevelopmental effects in children from birth to 18 years of age, published between 2002 and 2012 in English or Spanish. Twenty-seven articles met the eligibility criteria. Studies were rated for evidential consideration as high, intermediate, or low based upon the study design, number of participants, exposure measurement, and neurodevelopmental measures. All but one of the 27 studies evaluated showed some negative effects of pesticides on neurobehavioral development. A positive dose-response relationship between OP exposure and neurodevelopmental outcomes was found in all but one of the 12 studies that assessed dose-response. In the ten longitudinal studies that assessed prenatal exposure to OPs, cognitive deficits (related to working memory) were found in children at age 7 years, behavioral deficits (related to attention) seen mainly in toddlers, and motor deficits (abnormal reflexes) seen mainly in neonates. No meta-analysis was possible due to different measurements of exposure assessment and outcomes. Eleven studies (all longitudinal) were rated high, 14 studies were rated intermediate, and two studies were rated low. Evidence of neurological deficits associated with exposure to OP pesticides in children is growing. The studies reviewed collectively support the hypothesis that exposure to OP pesticides induces neurotoxic effects. Further research is needed to understand effects associated with exposure in critical windows of development.

Repeated pesticide exposure among North Carolina migrant and seasonal farmworkers

BACKGROUNDnLimited data document the multiple and repeated pesticide absorption experienced by farmworkers in an agricultural season or their risk factors.nnnMETHODSnData were collected from 196 farmworkers four times at monthly intervals in 2007. Urine samples were tested for 12 pesticide urinary metabolites. Questionnaire data provided measures of exposure risks.nnnRESULTSnFarmworkers had at least one detection for many pesticide urinary metabolites; for example, 84.2% had at least one detection for acephate, 88.8% for 3,5,6-trichloro-2-pyridinol. Most farmworkers had multiple detections for specific metabolites; for example, 64.8% had two or more detections for acephate, 64.8% for 3,5,6-trichloro-2-pyridinol, 79.1% for 3-phenoxybenzoic acid, and 86.7% for 2,4-dichlorophenoxyacetic acid. Housing type had a consistent significant association with metabolite detections.nnnCONCLUSIONSnFarmworkers are exposed to multiple pesticides across an agricultural season, and they experience repeated exposures to the same pesticides. Reducing farmworker pesticide exposure and delineating the health outcomes of this exposure require more detailed data. Am. J. Ind. Med. 53:802-813, 2010. (c) 2010 Wiley-Liss, Inc.

Organophosphate pesticide levels in blood and urine of women and newborns living in an agricultural community.

Organophosphate pesticides are widely used and recent studies suggest associations of in utero exposures with adverse birth outcomes and neurodevelopment. Few studies have characterized organophosphate pesticides in human plasma or established how these levels correlate to urinary measurements. We measured organophosphate pesticide metabolites in maternal urine and chlorpyrifos and diazinon in maternal and cord plasma of subjects living in an agricultural area to compare levels in two different biological matrices. We also determined paraoxonase 1 (PON1) genotypes (PON1(192) and PON1(-108)) and PON1 substrate-specific activities in mothers and their newborns to examine whether PON1 may affect organophosphate pesticide measurements in blood and urine. Chlorpyrifos levels in plasma ranged from 0-1,726 ng/mL and non-zero levels were measured in 70.5% and 87.5% of maternal and cord samples, respectively. Diazinon levels were lower (0-0.5 ng/mL); non-zero levels were found in 33.3% of maternal plasma and 47.3% of cord plasma. Significant associations between organophosphate pesticide levels in blood and metabolite levels in urine were limited to models adjusting for PON1 levels. Increased maternal PON1 levels were associated with decreased odds of chlorpyrifos and diazinon detection (odds ratio(OR): 0.56 and 0.75, respectively). Blood organophosphate pesticide levels of study participants were similar in mothers and newborns and slightly higher than those reported in other populations. However, compared to their mothers, newborns have much lower quantities of the detoxifying PON1 enzyme suggesting that infants may be especially vulnerable to organophosphate pesticide exposures.

Heavy Metals and Couple Fecundity, the LIFE Study

The effect of heavy metals at environmentally relevant concentrations on couple fecundity has received limited study despite ubiquitous exposure. In 2005-2009, couples (n=501) desiring pregnancy and discontinuing contraception were recruited and asked to complete interviews and to provide blood specimens for the quantification of cadmium (μg L(-1)), lead (μg dL(-1)) and mercury (μg L(-1)) using inductively coupled plasma-mass spectrometry. Couples completed daily journals on lifestyle and intercourse along with menstruation and pregnancy testing for women. Couples were followed for 12 months or until pregnant. Fecundability odds ratios (FORs) and 95% confidence intervals (CIs) were estimated adjusting for age, body mass index, cotinine, and serum lipids in relation to female then male exposures. FORs <1 denote a longer time to pregnancy. In adjusted models, reduced FORs were observed for both female cadmium (0.78; 95% CI 0.63-0.97) and male lead (0.85; 95% CI 0.73-0.98) concentrations. When jointly modeling couples exposures, only male lead concentration significantly reduced the FOR (0.82; 95% CI 0.68, 0.97), though the FOR remained <1 for female cadmium (0.80; 95% CI 0.64, 1.00). This prospective couple based cohort with longitudinal capture of time to pregnancy is suggestive of cadmium and leads reproductive toxicity at environmentally relevant concentrations.

Association of Organophosphate Pesticide Exposure and Paraoxonase with Birth Outcome in Mexican-American Women

Background Epidemiologic studies suggest that maternal organophosphorus (OP) pesticide exposure is associated with poorer fetal growth, but findings are inconsistent. We explored whether paraoxonase (PON1), a key enzyme involved in detoxification of OPs, could be an effect modifier in this association. Methods The study population included 470 pregnant women enrolled in the CHAMACOS Study, a longitudinal cohort study of mothers and children living in an agricultural region of California. We analyzed urine samples collected from mothers twice during pregnancy for dialkyl phosphate (DAP) metabolites of OP pesticides. We analyzed maternal and fetal (cord) blood samples for PON1 genotype (PON1192 and PON1−108) and enzyme activity (paraoxonase and arylesterase). Infant birth weight, head circumference, and gestational age were obtained from medical records. Results Infants PON1 genotype and activity were associated with birth outcome, but mothers were not. Infants with the susceptible PON1−108TT genotype had shorter gestational age (βu200a=u200a−0.5 weeks, 95% Confidence Interval (CI): −0.9, 0.0) and smaller head circumference (βu200a=u200a−0.4 cm, 95% CI: −0.7, 0.0) than those with the PON1−108CC genotype. Infants arylesterase and paraoxonase activity were positively associated with gestational age. There was some evidence of effect modification with DAPs: maternal DAP concentrations were associated with shorter gestational age only among infants of the susceptible PON1−108TT genotype (p-valueinteractionu200a=u200a0.09). However, maternal DAP concentrations were associated with larger birth weight (p-valueinteractionu200a=u200a0.06) and head circumference (p-valueinteraction<0.01) in infants with non-susceptible genotypes. Conclusions Infants whose PON1 genotype and enzyme activity levels suggested that they might be more susceptible to the effects of OP pesticide exposure had decreased fetal growth and length of gestation. PON1 may be another factor contributing to preterm or low birth weight birth.

Attitudes toward E-Cigarettes, Reasons for Initiating E-Cigarette Use, and Changes in Smoking Behavior after Initiation: A Pilot Longitudinal Study of Regular Cigarette Smokers

Objectives We examined 1) changes in smoking and vaping behavior and associated cotinine levels and health status among regular smokers who were first-time e-cigarette purchasers and 2) attitudes, intentions, and restrictions regarding e-cigarettes. Methods We conducted a pilot longitudinal study with assessments of the aforementioned factors and salivary cotinine at weeks 0, 4, and 8. Eligibility criteria included being ≥18 years old, smoking ≥25 of the last 30 days, smoking ≥5 cigarettes per day (cpd), smoking regularly ≥1 year, and not having started using e-cigarettes. Of 72 individuals screened, 40 consented, 36 completed the baseline survey, and 83.3% and 72.2% were retained at weeks 4 and 8, respectively. Results Participants reduced cigarette consumption from baseline to week 4 and 8 (p’s < 0.001); 23.1% reported no cigarette use in the past month at week 8. There was no significant decrease in cotinine from baseline to week 4 or 8 (p’s = ns). At week 8, the majority reported improved health (65.4%), reduced smoker’s cough (57.7%), and improved sense of smell (53.8%) and taste (50.0%). The majority believed that e-cigarettes versus regular cigarettes have fewer health risks (97.2%) and that e-cigarettes have been shown to help smokers quit (80.6%) and reduce cigarette consumption (97.2%). In addition, the majority intended to use e-cigarettes as a complete replacement for regular cigarettes (69.4%) and reported no restriction on e-cigarette use in the home (63.9%) or car (80.6%). Conclusions Future research is needed to document the long-term impact on smoking behavior and health among cigarette smokers who initiate use of e-cigarettes.

Does the home environment and the sex of the child modify the adverse effects of prenatal exposure to chlorpyrifos on child working memory

Prenatal exposure to chlorpyrifos (CPF), an organophosphorus insecticide, has long been associated with delayed neurocognitive development and most recently with decrements in working memory at age 7. In the current paper, we expanded the previous work on CPF to investigate how additional biological and social environmental factors might create or explain differential neurodevelopmental susceptibility, focusing on main and moderating effects of the quality of the home environment (HOME) and child sex. We evaluate how the quality of the home environment (specifically, parental nurturance and environmental stimulation) and child sex interact with the adverse effects of prenatal CPF exposure on working memory at child age 7years. We did not observe a remediating effect of a high quality home environment (either parental nurturance or environmental stimulation) on the adverse effects of prenatal CPF exposure on working memory. However, we detected a borderline significant interaction between prenatal exposure to CPF and child sex (B (95% CI) for interaction term=-1.714 (-3.753 to 0.326)) suggesting males experience a greater decrement in working memory than females following prenatal CPF exposure. In addition, we detected a borderline interaction between parental nurturance and child sex (B (95% CI) for interaction term=1.490 (-0.518 to 3.499)) suggesting that, in terms of working memory, males benefit more from a nurturing environment than females. To our knowledge, this is the first investigation into factors that may inform an intervention strategy to reduce or reverse the cognitive deficits resulting from prenatal CPF exposure.