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Scholarly Works (59 results)

  • Thesis
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UC Berkeley Electronic Theses and Dissertations (2014)

There is a growing concern about excess manganese (Mn) exposure in pregnant women and children. Recent studies have reported adverse health effects in children living near Mn mining and/or transformation plants or drinking water contaminated with Mn. This dissertation focuses on environmental exposures to Mn in pregnant women and children living near agricultural fields treated with Mn-containing fungicides in Costa Rica and California, and their effects on fetal growth, length of gestation, and children's neurodevelopment.

Chapter 1 provides a general introduction to human exposure to Mn and highlights the background, significance and specific aims for each study/chapter.

Chapter 2 focuses on the environmental and lifestyle factors associated with Mn concentrations in pregnant women living near banana plantations with extensive aerial spraying of Mn-containing fungicide mancozeb in Costa Rica. For these analyses, Mn concentrations were measured in repeated blood and hair samples collected from 449 pregnant women enrolled in the Infants' Environmental Health Study (ISA). Mean blood Mn and geometric mean hair Mn concentrations were 24.4 μg/L (8.9-56.3) and 1.8 μg/g (0.05-53.3), respectively. Blood Mn concentrations were positively associated with gestational age at sampling (β = 0.2; 95% CI: 0.1, 0.2), number of household members (β = 0.4; 95% CI: 0.1, 0.6), and living in a house made of permeable and difficult-to-clean materials (β = 2.6; 95% CI: 1.3, 4.0); and inversely related to smoking (β = -3.1; 95% CI: -5.8, -0.3). Hair Mn concentrations were inversely associated with gestational age at sampling (% change = 0.8; 95% CI: -1.6, 0.0); and positively associated with living within 50 meters of a plantation (% change = 42.1; 95% CI: 14.2, 76.9) and Mn concentrations in drinking water (% change = 17.5; 95% CI: 12.2, 22.8). Findings from these analyses suggest that pregnant women living near banana plantations aerially sprayed with mancozeb may be environmentally exposed to Mn.

In Chapter 3 the association of prenatal blood and hair Mn concentrations with fetal growth and length of gestation in pregnant women and children living near banana plantations sprayed with mancozeb in Costa Rica was examined. Data on blood or hair Mn concentrations and birth outcomes were collected from 380 mother-infant pairs from the ISA study. Linear regression and generalized additive models were used in these analyses to test for linear and nonlinear associations. Mean (± SD) blood Mn concentration was 24.4 ± 6.6 μg/L and geometric mean (geometric SD) hair Mn concentration was 1.8 (3.2) μg/g. Hair Mn concentrations during the 2nd trimester and averaged over pregnancy were positively related to infant chest circumference (β for 10-fold increase = 0.6 cm; 95%CI: 0.2, 1.1; and β = 0.7 cm; 95%CI: 0.2, 1.2). Similarly, mean maternal hair Mn concentrations during pregnancy were associated with increased chest circumference (β for 10-fold increase = 1.32 cm; 95% CI: 0.54, 2.09) in infants whose mothers did not have gestational anemia but not in infants of mothers who had gestational anemia (β = 0.24 cm; 95% CI: -0.57, 1.05; pINT = 0.09). Mean maternal blood Mn concentrations during pregnancy were associated with decreased chest circumference in infants whose mothers were living below the poverty line (β for one-unit increase = -0.06 cm; 95% CI: -0.12, -0.01), but not in those living above poverty (β = 0.02 cm; 95% CI: -0.06, 0.09; pINT = 0.08). Mean maternal hair Mn concentrations were positively associated with length of gestation in infants born to women living below the poverty line (β for 10-fold increase = 4.11 days; 95% CI: 0.47, 7.75) but negatively associated in those living above poverty (β = -3.17 days; 95% CI: -7.93, 1.58; pINT = 0.03). In contrast to findings from previous studies, no linear or nonlinear associations of Mn concentrations with lowered birth weight or head circumference were observed. Nevertheless, hair Mn concentrations were related to larger chest circumference in infants born to women without gestational anemia and longer gestational durations in women living below the poverty line, while blood Mn concentrations were associated with smaller chest circumferences. The clinical significance of larger chest circumference, in the absence of an association between hair Mn concentrations and other measures of fetal growth in this study, is unknown. Inconsistencies between studies could be due to differences in the study population, sample size, time of biological sampling, and sources of Mn exposure.

In Chapter 4 the neurodevelopmental effects of early life exposure to Mn, indicated by prenatal and postnatal dentine Mn levels in children's deciduous teeth, were examined in school-age children living near agricultural fields treated with Mn-containing fungicides in California. Participants in these analyses included 247 children enrolled in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) study, a prospective cohort study in an agricultural area of California. Data on attention, cognition, memory, and motor functioning were collected from children at ages 7, 9, and 10.5 years. Generalized linear models and generalized additive models were used to test for linear and nonlinear associations, and generalized estimating equation models to assess longitudinal effects. Higher prenatal and postnatal dentine Mn levels were associated with improved cognitive abilities and fine motor coordination at 7, 9, and 10.5 years. Higher prenatal dentine Mn levels were associated with poorer attention at ages 7, 9, and 10.5 but only in boys and children born to mothers with higher lead exposure during pregnancy or gestational anemia. Higher postnatal dentine Mn levels were associated with better immediate and delayed memory at 9 and 10.5 years. Longitudinal models showed a weak association between postnatal dentine Mn levels and better cognitive outcomes at 7 and 10.5 years. These associations were all linear, and no threshold was observed. Previous studies have reported associations between childhood Mn exposure and negative neurodevelopmental effects, but in this study, small and positive relationships between postnatal dentine Mn and fine motor coordination, memory, and cognition were observed in children aged 7, 9, and 10.5 years. Disparities in findings between studies could be due to differences in the study design, timing of Mn measurements, exposure pathways, and/or exposure matrix.

Finally, Chapter 5 highlights the major findings for each chapter/study, conclusion, and future directions.

    Cover page: Exposure to manganese, fetal growth, and neurodevelopment in children living in agricultural communities in Costa Rica and California
    • Article
    • Peer Reviewed
    UC Berkeley Previously Published Works (2021)
    Studies suggest that acute pesticide poisonings (APP) may be linked with long-term neurological effects. To examine long-term neurological and psychological distress symptoms associated with having experienced an APP, we conducted a cross-sectional study of 300 conventional and organic smallholder farmers from Zarcero County, Costa Rica, May-August 2016. We collected self-reported data on sociodemographic characteristics, occupational history, pesticide exposure, APPs, neurological and psychological distress symptoms (using the Brief Symptom Inventory (BSI)). Adjusted logistic regression models were fit. A total of 14% of the farmers (98% male) reported experiencing at least one APP during their lifetime. Self-reported APP was associated with neurological symptoms during the 12 months prior to interview (e.g., fainting (Odds Ratio: 7.48, 95% Confidence Interval: 1.83, 30.74), shaking hands (3.50; 1.60, 7.60), numbness/tingling in hands or feet (3.23; 1.66, 6.32), insomnia (2.53; 1.34, 4.79), accelerated heartrate (2.42; 1.03, 5.47), dizziness (2.38; 1.19, 4.72), increased irritability/anger (2.37; 1.23, 4.55), low energy (2.33; 1.23, 4.46), and difficulty concentrating (2.01; 1.05, 3.85)). Farmers who reported an APP in the ten years prior to interview experienced increased odds of abnormal BSI scores for hostility (4.51; 1.16, 17.70) and paranoid ideation (3.76; 0.99, 18.18). Having experienced an APP may be associated with long-term neurological and psychological distress symptoms.
      Cover page: Long-Term Neurological and Psychological Distress Symptoms among Smallholder Farmers in Costa Rica with a History of Acute Pesticide Poisoning.
      • Article
      • Peer Reviewed
      UC Berkeley Previously Published Works (2014)
      Manganese (Mn) is an essential nutrient but at high exposure levels is a neurotoxicant. There is no well-validated biomarker to assess perinatal Mn exposure. A total of 75 mother-child pairs provided blood, urine, and/or deciduous tooth samples. We analyzed Mn in dentin and enamel of shed teeth; maternal, cord, and child blood; and maternal and child urine and examined the interrelationships of Mn levels in all matrices. We observed higher Mn levels in prenatal than postnatal dentin (geometric mean (GM) = 0.51 vs 0.16 Mn:Ca, p < 0.001), maternal blood at delivery than 26 weeks gestation (GM = 20.7 vs. 14.6 μg/L, p = 0.001), and cord blood than child blood at 24 months of age (39.9 vs 25.0 μg/L, p = 0.005). There were no significant correlations between Mn in dentin and Mn concentrations in maternal blood or maternal or child urine. Levels of Mn in prenatal dentin, prenatal maternal blood, and 24 month urine were higher (p < 0.05) among mothers and children living with a farm worker. Prenatal Mn levels in dentin were correlated with Mn loadings and concentrations in prenatal house dust. Levels of Mn measured in tooth dentin constitute a promising biomarker of perinatal exposure.
        Cover page: Biomarkers of Manganese Exposure in Pregnant Women and Children Living in an Agricultural Community in California
        • Article
        • Peer Reviewed
        UC Berkeley Previously Published Works (2018)
        Evidence suggests that early-life exposure to pesticides inside the home may be associated with childhood leukemia, however data from Latin American countries are limited. We examined whether self-reported maternal residential pesticide use and nearby pesticide applications-before and after childs birth-were associated with acute lymphoblastic leukemia (ALL) in the Costa Rican Childhood Leukemia Study (CRCLS), a population-based case-control study (2001-2003). Cases (n = 251 ALL) were diagnosed between 1995 and 2000 (age <15 years at diagnosis) and were identified through the Costa Rican Cancer Registry and National Childrens Hospital. Population controls (n = 577) were drawn from the National Birth Registry. We fitted unconditional logistic regression models adjusted for child sex, birth year, and socioeconomic status to estimate the exposure-outcome associations and also stratified by child sex. We observed that self-reported maternal insecticide use inside the home in the year before pregnancy, during pregnancy, and while breastfeeding was associated with increased odds of ALL among boys [adjusted Odds Ratio (aOR) = 1.63 (95% confidence interval [95% CI]: 1.05-2.53), 1.75 (1.13-2.73), and 1.75 (1.12-2.73), respectively. We also found evidence of exposure-response relationships between more frequent maternal insecticide use inside the home and increased odds of ALL among boys and girls combined. Maternal report of pesticide applications on farms or companies near the home during pregnancy and at any time period were also associated with ALL. Our study in Costa Rica highlights the need for education to minimize pesticide exposures inside and around the home, particularly during pregnancy and breastfeeding.
          Cover page: Maternal residential pesticide use and risk of childhood leukemia in Costa Rica.
          • Article
          • Peer Reviewed
          UC Berkeley Previously Published Works (2018)
          Evidence suggests that early-life exposure to pesticides inside the home may be associated with childhood leukemia, however data from Latin American countries are limited. We examined whether self-reported maternal residential pesticide use and nearby pesticide applications-before and after child's birth-were associated with acute lymphoblastic leukemia (ALL) in the Costa Rican Childhood Leukemia Study (CRCLS), a population-based case-control study (2001-2003). Cases (n = 251 ALL) were diagnosed between 1995 and 2000 (age <15 years at diagnosis) and were identified through the Costa Rican Cancer Registry and National Children's Hospital. Population controls (n = 577) were drawn from the National Birth Registry. We fitted unconditional logistic regression models adjusted for child sex, birth year, and socioeconomic status to estimate the exposure-outcome associations and also stratified by child sex. We observed that self-reported maternal insecticide use inside the home in the year before pregnancy, during pregnancy, and while breastfeeding was associated with increased odds of ALL among boys [adjusted Odds Ratio (aOR) = 1.63 (95% confidence interval [95% CI]: 1.05-2.53), 1.75 (1.13-2.73), and 1.75 (1.12-2.73), respectively. We also found evidence of exposure-response relationships between more frequent maternal insecticide use inside the home and increased odds of ALL among boys and girls combined. Maternal report of pesticide applications on farms or companies near the home during pregnancy and at any time period were also associated with ALL. Our study in Costa Rica highlights the need for education to minimize pesticide exposures inside and around the home, particularly during pregnancy and breastfeeding.
            Cover page: Maternal residential pesticide use and risk of childhood leukemia in Costa Rica
            • Article
            • Peer Reviewed
            UC Berkeley Previously Published Works (2021)
            Exposures to phthalates, parabens, and other phenols are often correlated due to their ubiquitous use in personal care products and plastics. Examining these compounds as a complex mixture may clarify inconsistent relationships between individual chemicals and childhood adiposity. Using data from the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) study, a longitudinal cohort of children in Salinas Valley, California (n = 309), we examined biomarkers of 11 phthalate metabolites and 9 phenols, including several parabens and bisphenol A, measured in maternal urine at two time points during pregnancy. We measured child height and weight at age five to calculate the body mass index (BMI) z-scores and overweight/obesity status. The association between prenatal urinary concentrations of biomarkers with the childhood BMI z-score and overweight/obesity status was analyzed using single-pollutant models and two mixture methods: Bayesian hierarchical modeling (BMH) and Bayesian kernel machine regression (BKMR). Urinary concentrations of monoethyl phthalate, monocarboxy-isononly phthalate (metabolites of diethyl phthalate and di-isodecyl phthalate, respectively), and propylparaben were consistently associated with an increased BMI z-score and overweight/obesity status across all modeling approaches. Higher prenatal exposures to the cumulative biomarker mixture also trended with greater childhood adiposity. These results, robust across two methods that control for co-pollutant confounding, suggest that prenatal exposure to certain phthalates and parabens may increase the risk for obesity in early childhood.
              Cover page: Prenatal Exposure to Mixtures of Phthalates, Parabens, and Other Phenols and Obesity in Five-Year-Olds in the CHAMACOS Cohort
              • Article
              • Peer Reviewed
              UC Davis Previously Published Works (2015)

              Background

              The overall burden of chronic disease, inflammation and cardiovascular risk increases with age. Whether the relationship between age and inflammation is impacted by presence of an adverse metabolic burden is not known.

              Methods

              We determined inflammatory markers in humans (336 Caucasians and 224 African Americans) and in mice, representing a spectrum of age, weight and metabolic burden.

              Results

              In humans, levels of inflammatory markers increased significantly with age in subjects without the metabolic syndrome, (P=0.009 and P=0.037 for C-reactive protein, P<0.001 and P=0.001 for fibrinogen, P<0.001 and P=0.005 for serum amyloid-A, for Caucasians and African Americans, respectively). In contrast, trend patterns of inflammatory markers did not change significantly with age in subjects with metabolic syndrome in either ethnic group, except for fibrinogen in Caucasians. A composite z-score for systemic inflammation increased significantly with age in subjects without metabolic syndrome (P=0.004 and P<0.006 for Caucasians and African Americans, respectively) but not in subjects with metabolic syndrome (P=0.009 for difference in age trend between metabolic syndrome and non-metabolic syndrome). In contrast, no similar age trend was found in vascular inflammation. The findings in humans were paralleled by results in mice as serum amyloid-A levels increased across age (range 2-15 months, P<0.01) and were higher in ob/ob mice compared to control mice (P<0.001).

              Conclusions

              Presence of a metabolic challenge in mice and humans influences levels of inflammatory markers over a wide age range. Our results underscore that already at a young age, presence of a metabolic burden enhances inflammation to a level that appears to be similar to that of decades older people without metabolic syndrome.
                Cover page: Attenuated Age-Impact on Systemic Inflammatory Markers in the Presence of a Metabolic Burden
                • Article
                • Peer Reviewed
                UC Berkeley Previously Published Works (2017)

                Summary

                The widespread application of functional neuroimaging within the field of environmental epidemiology has the potential to greatly enhance our understanding of how environmental toxicants affect brain function. Because many epidemiological studies take place in remote and frequently changing environments, it is necessary that the primary neuroimaging approach adopted by the epidemiology community be robust to many environments, easy to use, and, preferably, mobile. Here, we outline our use of functional near-infrared spectroscopy (fNIRS) to collect functional brain imaging data from Costa Rican farm workers enrolled in an epidemiological study on the health effects of chronic pesticide exposure. While couched in this perspective, we focus on the methodological considerations that are necessary to conduct a mobile fNIRS study in a diverse range of environments. Thus, this guide is intended to be generalizable to all research scenarios and projects in which fNIRS may be used to collect functional brain imaging data in epidemiological field surveys. https://doi.org/10.1289/EHP2049.
                  Cover page: Portable Functional Neuroimaging as an Environmental Epidemiology Tool: A How-To Guide for the Use of fNIRS in Field Studies
                  • Article
                  • Peer Reviewed
                  UC Berkeley Previously Published Works (2024)
                  PURPOSE: To examine associations of prenatal biomarkers of pesticide exposure with birth size measures and length of gestation among newborns from the Infants Environmental Health (ISA) birth cohort, Costa Rica. METHODS: We included 386 singleton liveborn newborns with data on birth size measures, length of gestation, and maternal urinary biomarkers of chlorpyrifos, synthetic pyrethroids, mancozeb, pyrimethanil, and 2, 4-D during pregnancy. We associated biomarkers of exposure with birth outcomes using multivariate linear regression and generalized additive models. RESULTS: Concentrations were highest for ethylene thiourea (ETU, metabolite of mancozeb), median = 3.40; p10-90 = 1.90-6.79 µg/L, followed by 3,5,6-trichloro-2-pyridinol (TCP, metabolite of chlorpyrifos) p50 = 1.76 p10-90 = 0.97-4.36 µg/L, and lowest for 2,4-D (p50 = 0.33 p10-90 = 0.18-1.07 µg/L). Among term newborns (≥37 weeks), higher prenatal TCP was associated with lower birth weight and smaller head circumference (e.g., β per 10-fold-increase) during the second half of pregnancy = -129.6 (95% confidence interval [CI] = -255.8, -3.5) grams, and -0.61 (95% CI = -1.05, -0.17) centimeters, respectively. Also, among term newborns, prenatal 2,4-D was associated with lower birth weight (β per 10-fold-increase = -125.1; 95% CI = -228.8, -21.5), smaller head circumference (β = -0.41; 95% CI = -0.78, -0.03), and, during the second half of pregnancy, with shorter body length (β = -0.58; 95% CI = -1.09, -0.07). Furthermore, ETU was nonlinearly associated with head circumference during the second half of pregnancy. Biomarkers of pyrethroids and pyrimethanil were not associated with birth size, and none of the biomarkers explained the length of gestation. CONCLUSIONS: Prenatal exposure to chlorpyrifos and 2,4-D, and, possibly, mancozeb/ETU, may impair fetal growth.
                    Cover page: Pesticide exposure, birth size, and gestational age in the ISA birth cohort, Costa Rica.
                    • Peer Reviewed
                    UC Berkeley Previously Published Works (2021)
                    Approximately 75% of farmworkers in the United States are Latino migrants, and about 50% of hired farmworkers do not have authorization to work in the United States. Farmworkers face numerous chemical, physical, and biological threats to their health. The adverse effects of these hazards may be amplified among Latino migrant farmworkers, who are concurrently exposed to various psychosocial stressors. Factors such as documentation status, potential lack of authorization to work in the United States, and language and cultural barriers may also prevent Latino migrants from accessing federal aid, legal assistance, and health programs. These environmental, occupational, and social hazards may further exacerbate existing health disparities among US Latinos. This population is also likely to be disproportionately impacted by emerging threats, including climate change and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Latino migrant farmworkers are essential to agriculture in the United States, and actions are needed to protect this vulnerable population.
                      Cover page: Environmental Health Threats to Latino Migrant Farmworkers
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