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Dimitrov LV, Kaminski JW, Holbrook JR, Bitsko RH, Yeh M, Courtney JG, O'Masta B, Maher B, Cerles A, McGowan K, Rush M. A Systematic Review and Meta-analysis of Chemical Exposures and Attention-Deficit/Hyperactivity Disorder in Children. PREVENTION SCIENCE : THE OFFICIAL JOURNAL OF THE SOCIETY FOR PREVENTION RESEARCH 2024; 25:225-248. [PMID: 38108946 PMCID: PMC11132938 DOI: 10.1007/s11121-023-01601-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/17/2023] [Indexed: 12/19/2023]
Abstract
Exposure to certain chemicals prenatally and in childhood can impact development and may increase risk for attention-deficit/hyperactivity disorder (ADHD). Leveraging a larger set of literature searches conducted to synthesize results from longitudinal studies of potentially modifiable risk factors for childhood ADHD, we present meta-analytic results from 66 studies that examined the associations between early chemical exposures and later ADHD diagnosis or symptoms. Studies were eligible for inclusion if the chemical exposure occurred at least 6 months prior to measurement of ADHD diagnosis or symptomatology. Included papers were published between 1975 and 2019 on exposure to anesthetics (n = 5), cadmium (n = 3), hexachlorobenzene (n = 4), lead (n = 22), mercury (n = 12), organophosphates (n = 7), and polychlorinated biphenyls (n = 13). Analyses are presented for each chemical exposure by type of ADHD outcome reported (categorical vs. continuous), type of ADHD measurement (overall measures of ADHD, ADHD symptoms only, ADHD diagnosis only, inattention only, hyperactivity/impulsivity only), and timing of exposure (prenatal vs. childhood vs. cumulative), whenever at least 3 relevant effect sizes were available. Childhood lead exposure was positively associated with ADHD diagnosis and symptoms in all analyses except for the prenatal analyses (odds ratios (ORs) ranging from 1.60 to 2.62, correlation coefficients (CCs) ranging from 0.14 to 0.16). Other statistically significant associations were limited to organophosphates (CC = 0.11, 95% confidence interval (CI): 0.03-0.19 for continuous measures of ADHD outcomes overall), polychlorinated biphenyls (CC = 0.08, 95% CI: 0.02-0.14 for continuous measures of inattention as the outcome), and both prenatal and childhood mercury exposure (CC = 0.02, 95% CI: 0.00-0.04 for continuous measures of ADHD outcomes overall for either exposure window). Our findings provide further support for negative impacts of prenatal and/or childhood exposure to certain chemicals and raise the possibility that primary prevention and targeted screening could prevent or mitigate ADHD symptomatology. Furthermore, these findings support the need for regular review of regulations as our scientific understanding of the risks posed by these chemicals evolves.
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Affiliation(s)
- Lina V Dimitrov
- Division of Human Development and Disability, National Center On Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, GA, USA.
- Oak Ridge Institute for Science and Education, Oak Ridge, TN, USA.
| | - Jennifer W Kaminski
- Division of Human Development and Disability, National Center On Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Joseph R Holbrook
- Division of Human Development and Disability, National Center On Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Rebecca H Bitsko
- Division of Human Development and Disability, National Center On Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Michael Yeh
- Division of Environmental Health Science and Practice, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Joseph G Courtney
- Division of Environmental Health Science and Practice, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | | | - Brion Maher
- Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
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Wylie AC, Short SJ, Fry RC, Mills-Koonce WR, Propper CB. Maternal prenatal lead levels and neonatal brain volumes: Testing moderations by maternal depressive symptoms and family income. Neurotoxicol Teratol 2024; 102:107322. [PMID: 38244816 PMCID: PMC10990786 DOI: 10.1016/j.ntt.2024.107322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 01/17/2024] [Accepted: 01/17/2024] [Indexed: 01/22/2024]
Abstract
There is considerable evidence that prenatal lead exposure is detrimental to child cognitive and socio-emotional development. Further evidence suggests that the effects of prenatal lead on developmental outcomes may be conditional upon exposure to social stressors, such as maternal depression and low socioeconomic status. However, no studies have examined associations between these co-occurring stressors during pregnancy and neonatal brain volumes. Leveraging a sample of 101 mother-infant dyads followed beginning in mid-pregnancy, we examined the main effects of prenatal urinary lead levels on neonatal lateralized brain volumes (left and right hippocampus, amygdala, cerebellum, frontal lobes) and total gray matter. We additionally tested for moderations between lead and depressive symptoms and between lead and family income relative to the federal poverty level (FPL) on the same neurodevelopmental outcomes. Analyses of main effects indicated that prenatal lead was significantly (ps < 0.05) associated with reduced right and left amygdala volumes (βs = -0.23- -0.20). The testing and probing of cross-product interaction terms using simple slopes indicated that the negative effect of lead on the left amygdala was conditional upon mothers having low depressive symptoms or high income relative to the FPL. We interpret the results in the context of trajectories of prenatal and postnatal brain development and susceptibility to low levels of prenatal lead in the context of other social stressors.
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Affiliation(s)
- Amanda C Wylie
- Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, United States; Frank Porter Graham Child Development Institute, University of North Carolina at Chapel Hill, United States.
| | - Sarah J Short
- Department of Educational Psychology, University of Wisconsin-Madison, United States; Center for Healthy Minds, University of Wisconsin-Madison, United States
| | - Rebecca C Fry
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, United States; Institute for Environmental Health Solutions, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, United States
| | - W Roger Mills-Koonce
- School of Education, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Cathi B Propper
- Frank Porter Graham Child Development Institute, University of North Carolina at Chapel Hill, United States; School of Nursing, University of North Carolina at Chapel Hill, United States
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Ames JL, Burjak M, Avalos LA, Braun JM, Bulka CM, Croen LA, Dunlop AL, Ferrara A, Fry RC, Hedderson MM, Karagas MR, Liang D, Lin PID, Lyall K, Moore B, Morello-Frosch R, O’Connor TG, Oh J, Padula AM, Woodruff TJ, Zhu Y, Hamra GB. Prenatal Exposure to Per- and Polyfluoroalkyl Substances and Childhood Autism-related Outcomes. Epidemiology 2023; 34:450-459. [PMID: 36630444 PMCID: PMC10074577 DOI: 10.1097/ede.0000000000001587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
BACKGROUND Epidemiologic evidence linking prenatal exposure to per- and polyfluoroalkyl substances (PFAS) with altered neurodevelopment is inconclusive, and few large studies have focused on autism-related outcomes. We investigated whether blood concentrations of PFAS in pregnancy are associated with child autism-related outcomes. METHODS We included 10 cohorts from the National Institutes of Health (NIH)-funded Environmental influences on Child Health Outcomes (ECHO) program (n = 1,429). We measured 14 PFAS analytes in maternal blood collected during pregnancy; eight analytes met detection criteria for analysis. We assessed quantitative autism-related traits in children via parent report on the Social Responsiveness Scale (SRS). In multivariable linear models, we examined relationships of each PFAS (natural log-transformed) with SRS scores. We further modeled PFAS as a complex mixture using Bayesian methods and examined modification of these relationships by child sex. RESULTS Most PFAS in maternal blood were not associated with child SRS T-scores. Perfluorononanoic acid (PFNA) showed the strongest and most consistent association: each 1-unit increase in ln-transformed PFNA was associated with greater autism-related traits (adjusted β [95% confidence interval (CI)] = 1.5 [-0.1, 3.0]). The summed mixture, which included six PFAS detected in >70% of participants, was not associated with SRS T-scores (adjusted β [95% highest posterior density interval] = 0.7 [-1.4, 3.0]). We did not observe consistent evidence of sex differences. CONCLUSIONS Prenatal blood concentrations of PFNA may be associated with modest increases in child autism-related traits. Future work should continue to examine the relationship between exposures to both legacy and emerging PFAS and additional dimensional, quantitative measures of childhood autism-related outcomes.
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Affiliation(s)
- Jennifer L. Ames
- Division of Research, Kaiser Permanente Northern California, Oakland, CA USA
| | | | - Lyndsay A. Avalos
- Division of Research, Kaiser Permanente Northern California, Oakland, CA USA
| | - Joseph M. Braun
- Department of Epidemiology, Brown University, Providence, RI USA
| | | | - Lisa A. Croen
- Division of Research, Kaiser Permanente Northern California, Oakland, CA USA
| | - Anne L. Dunlop
- Department of Gynecology and Obstetrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Assiamira Ferrara
- Division of Research, Kaiser Permanente Northern California, Oakland, CA USA
| | - Rebecca C. Fry
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC USA
| | | | | | - Donghai Liang
- Gangarosa Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA USA
| | - Pi-I D. Lin
- Division of Chronic Disease Research Across the Lifecourse (CoRAL), Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, MA USA
| | - Kristen Lyall
- A.J. Drexel Autism Institute, Drexel University, Philadelphia, PA USA
| | - Brianna Moore
- Department of Epidemiology, Colorado School of Public Health, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA
| | | | | | - Jiwon Oh
- Department of Public Health Sciences, University of California, Davis, Davis CA, USA
| | - Amy M. Padula
- Program on Reproductive Health and the Environment, Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, CA USA
| | - Tracey J. Woodruff
- Program on Reproductive Health and the Environment, Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, CA USA
| | - Yeyi Zhu
- Division of Research, Kaiser Permanente Northern California, Oakland, CA USA
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Wylie AC, Short SJ. Environmental Toxicants and the Developing Brain. Biol Psychiatry 2023; 93:921-933. [PMID: 36906498 DOI: 10.1016/j.biopsych.2023.01.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 01/05/2023] [Accepted: 01/11/2023] [Indexed: 01/19/2023]
Abstract
Early life represents the most rapid and foundational period of brain development and a time of vulnerability to environmental insults. Evidence indicates that greater exposure to ubiquitous toxicants like fine particulate matter (PM2.5), manganese, and many phthalates is associated with altered developmental, physical health, and mental health trajectories across the lifespan. Whereas animal models offer evidence of their mechanistic effects on neurological development, there is little research that evaluates how these environmental toxicants are associated with human neurodevelopment using neuroimaging measures in infant and pediatric populations. This review provides an overview of 3 environmental toxicants of interest in neurodevelopment that are prevalent worldwide in the air, soil, food, water, and/or products of everyday life: fine particulate matter (PM2.5), manganese, and phthalates. We summarize mechanistic evidence from animal models for their roles in neurodevelopment, highlight prior research that has examined these toxicants with pediatric developmental and psychiatric outcomes, and provide a narrative review of the limited number of studies that have examined these toxicants using neuroimaging with pediatric populations. We conclude with a discussion of suggested directions that will move this field forward, including the incorporation of environmental toxicant assessment in large, longitudinal, multimodal neuroimaging studies; the use of multidimensional data analysis strategies; and the importance of studying the combined effects of environmental and psychosocial stressors and buffers on neurodevelopment. Collectively, these strategies will improve ecological validity and our understanding of how environmental toxicants affect long-term sequelae via alterations to brain structure and function.
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Affiliation(s)
- Amanda C Wylie
- Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Frank Porter Graham Child Development Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Sarah J Short
- Department of Educational Psychology, University of Wisconsin-Madison, Madison, Wisconsin; Center for Health Minds, University of Wisconsin-Madison, Madison, Wisconsin.
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Wallace ER, Buth E, Szpiro AA, Ni Y, Loftus CT, Masterson E, Day DB, Sun BZ, Sullivan A, Barrett E, Nguyen RH, Robinson M, Kannan K, Mason A, Sathyanarayana S, LeWinn KZ, Bush NR, Karr CJ. Prenatal exposure to polycyclic aromatic hydrocarbons is not associated with behavior problems in preschool and early school-aged children: A prospective multi-cohort study. ENVIRONMENTAL RESEARCH 2023; 216:114759. [PMID: 36370819 PMCID: PMC9817935 DOI: 10.1016/j.envres.2022.114759] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 11/02/2022] [Accepted: 11/05/2022] [Indexed: 05/31/2023]
Abstract
BACKGROUND Epidemiological study findings are inconsistent regarding associations between prenatal polycyclic aromatic hydrocarbon (PAH) exposures and childhood behavior. This study examined associations of prenatal PAH exposure with behavior at age 4-6 years in a large, diverse, multi-region prospective cohort. Secondary aims included examination of PAH mixtures and effect modification by child sex, breastfeeding, and child neighborhood opportunity. METHODS The ECHO PATHWAYS Consortium pooled 1118 mother-child dyads from three prospective pregnancy cohorts in six U.S. cities. Seven PAH metabolites were measured in prenatal urine. Child behavior was assessed at age 4-6 using the Total Problems score from the Child Behavior Checklist (CBCL). Neighborhood opportunity was assessed using the socioeconomic and educational scales of the Child Opportunity Index. Multivariable linear regression was used to estimate associations per 2-fold increase in each PAH metabolite, adjusted for demographic, prenatal, and maternal factors and using interaction terms for effect modifiers. Associations with PAH mixtures were estimated using Weighted Quantile Sum Regression (WQSR). RESULTS The sample was racially and sociodemographically diverse (38% Black, 49% White, 7% Other; household-adjusted income range $2651-$221,102). In fully adjusted models, each 2-fold increase in 2-hydroxynaphthalene was associated with a lower Total Problems score, contrary to hypotheses (b = -0.80, 95% CI = -1.51, -0.08). Associations were notable in boys (b = -1.10, 95% CI = -2.11, -0.08) and among children breastfed 6+ months (b = -1.31, 95% CI = -2.25, -0.37), although there was no statistically significant evidence for interaction by child sex, breastfeeding, or neighborhood child opportunity. Associations were null for other PAH metabolites; there was no evidence of associations with PAH mixtures from WQSR. CONCLUSION In this large, well-characterized, prospective study of mother-child pairs, prenatal PAH exposure was not associated with child behavior problems. Future studies characterizing the magnitude of prenatal PAH exposure and studies in older childhood are needed.
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Affiliation(s)
- Erin R Wallace
- Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA, USA.
| | - Erin Buth
- Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA, USA
| | - Adam A Szpiro
- Department of Biostatistics, School of Public Health, University of Washington, Seattle, WA, USA
| | - Yu Ni
- Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA, USA
| | - Christine T Loftus
- Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA, USA
| | - Erin Masterson
- Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA, USA
| | - Drew B Day
- Seattle Children's Research Institute, Seattle, WA, USA
| | - Bob Z Sun
- Department of Pediatrics, School of Medicine, University of Washington, Seattle, WA, USA
| | - Alexis Sullivan
- Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California, San Francisco, San Francisco, California, USA
| | - Emily Barrett
- Department of Biostatistics and Epidemiology, Environmental and Occupational Health Sciences Institute, School of Public Health, Rutgers University, Piscataway, NJ, USA
| | - Ruby Hn Nguyen
- Division of Epidemiology and Community Health, University of Minnesota, Minneapolis, MN, USA
| | - Morgan Robinson
- Department of Pediatrics and Department of Environmental Medicine, New York University School of Medicine, New York, NY, 10016, USA
| | - Kurunthachalam Kannan
- Department of Pediatrics and Department of Environmental Medicine, New York University School of Medicine, New York, NY, 10016, USA
| | - Alex Mason
- Department of Preventive Medicine, University of Tennessee Health Sciences Center, Memphis, TN, USA
| | - Sheela Sathyanarayana
- Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA, USA; Seattle Children's Research Institute, Seattle, WA, USA; Department of Pediatrics, School of Medicine, University of Washington, Seattle, WA, USA
| | - Kaja Z LeWinn
- Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California, San Francisco, San Francisco, California, USA
| | - Nicole R Bush
- Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California, San Francisco, San Francisco, California, USA; Department of Pediatrics, School of Medicine, University of California, San Francisco, San Francisco, California, USA
| | - Catherine J Karr
- Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA, USA; Department of Pediatrics, School of Medicine, University of Washington, Seattle, WA, USA; Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA, USA
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Goodman CV, Bashash M, Green R, Song P, Peterson KE, Schnaas L, Mercado-García A, Martínez-Medina S, Hernández-Avila M, Martinez-Mier A, Téllez-Rojo MM, Hu H, Till C. Domain-specific effects of prenatal fluoride exposure on child IQ at 4, 5, and 6-12 years in the ELEMENT cohort. ENVIRONMENTAL RESEARCH 2022; 211:112993. [PMID: 35276192 PMCID: PMC9890727 DOI: 10.1016/j.envres.2022.112993] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 02/13/2022] [Accepted: 02/19/2022] [Indexed: 05/17/2023]
Abstract
OBJECTIVE Prenatal exposure to fluoride has been associated with adverse neurodevelopmental outcomes. However, the neuropsychological profile of fluoride's developmental neurotoxicity at low levels and the stability of this relationship across childhood has not been characterized. We investigated the longitudinal and domain specific effect of prenatal fluoride exposure on IQ among children ages 4, 5, and 6-12 years in the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) cohort. METHODS We measured the average of maternal urinary fluoride at each trimester of pregnancy adjusted for creatinine (MUFCRE). Children were administered the McCarthy Scales of Children's Abilities at ages 4 (N = 386) and 5 (N = 308), and the Wechsler Abbreviated Scale of Intelligence at age 6-12 (N = 278). We used generalized estimating equation (GEE) models to estimate the population averaged effect of MUFCRE concentration on longitudinal General Cognitive Index (GCI)/Full-Scale IQ (FSIQ), Verbal IQ (VIQ), and Performance IQ (PIQ) scores (N = 348). We tested for possible interactions between MUFCRE and child sex as well as for MUFCRE and time point on children's IQ. All models controlled for relevant available covariates. RESULTS The mean/median MUFCRE concentration was 0.90/0.83 mg/L (SD = 0.39; IQR, 0.64-1.11 mg/L). A 0.5 mg/L increase in MUFCRE predicted an average 2.12-point decrease in GCI/FSIQ (95% CI: -3.49, -0.75) and 2.63-point decrease in PIQ (95% CI: -3.87, -1.40). MUFCRE was marginally associated with VIQ across time (B = -1.29, 95% CI: -2.60, 0.01). No interactions between MUFCRE and child sex or MUFCRE and time were observed. CONCLUSION The negative association between prenatal fluoride exposure and longitudinal IQ was driven by decrements in non-verbal intelligence (i.e. PIQ), suggesting that visual-spatial and perceptual reasoning abilities may be more impacted by prenatal fluoride exposure as compared to verbal abilities.
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Affiliation(s)
- Carly V Goodman
- Faculty of Health, York University, Toronto, Ontario, Canada
| | - Morteza Bashash
- Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | - Rivka Green
- Faculty of Health, York University, Toronto, Ontario, Canada
| | - Peter Song
- School of Public Health, University of Michigan, Ann Arbor, MI, USA
| | - Karen E Peterson
- School of Public Health, University of Michigan, Ann Arbor, MI, USA
| | | | | | | | | | | | | | - Howard Hu
- Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | - Christine Till
- Faculty of Health, York University, Toronto, Ontario, Canada
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Hyland C, Bradshaw P, Deardorff J, Gunier RB, Mora AM, Kogut K, Sagiv SK, Bradman A, Eskenazi B. Interactions of agricultural pesticide use near home during pregnancy and adverse childhood experiences on adolescent neurobehavioral development in the CHAMACOS study. ENVIRONMENTAL RESEARCH 2022; 204:111908. [PMID: 34425114 DOI: 10.1016/j.envres.2021.111908] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 08/16/2021] [Accepted: 08/17/2021] [Indexed: 05/12/2023]
Abstract
BACKGROUND Studies have documented independent adverse associations between prenatal and early-life exposure to environmental chemicals and social adversity with child neurodevelopment; however, few have considered these exposures jointly. The objective of this analysis is to examine whether associations of pesticide mixtures and adolescent neurobehavioral development are modified by early-life adversity in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) cohort. METHODS We used linear mixed effects Bayesian Hierarchical Models (BHM) to examine the joint effect of applications of 11 agricultural pesticides within 1 km of maternal homes during pregnancy and youth-reported Adverse Childhood Experiences (ACEs) with maternal and youth-reported internalizing behaviors, hyperactivity, and attention problems assessed via the Behavior Assessment for Children (BASC) (mean = 50, standard deviation = 10) at ages 16 and 18 years (n = 458). RESULTS The median (25th-75th percentiles) of ACEs was 1 (0-3); 72.3% of participants had low ACEs (0-2 events) and 27.7% had ACEs (3+ events). Overall, there was little evidence of modification of exposure-outcome associations by ACEs. A two-fold increase in malathion use was associated with increased internalizing behaviors among those with high ACEs from both maternal- (β = 1.9; 95% Credible Interval (CrI): 0.2, 3.7 for high ACEs vs. β = -0.1; 95% CrI: 1.2, 0.9 for low ACEs) and youth-report (β = 2.1; 95% CrI: 0.4, 3.8 for high ACEs vs. β = 0.2; 95% CrI: 0.8, 1.2 for low ACEs). Applications of malathion and dimethoate were also associated with higher youth-reported hyperactivity and/or inattention among those with high ACEs. CONCLUSION We observed little evidence of effect modification of agricultural pesticide use near the home during pregnancy and adolescent behavioral problems by child ACEs. Future studies should examine critical windows of susceptibility of exposure to chemical and non-chemical stressors and should consider biomarker-based exposure assessment methods.
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Affiliation(s)
- Carly Hyland
- Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California at Berkeley, Berkeley, CA, United States; Department of Public Health and Population Science, College of Health Sciences, Boise State University, Boise, ID, United States
| | - Patrick Bradshaw
- Division of Epidemiology, School of Public Health, University of California, Berkeley, Berkeley, CA, United States
| | - Julianna Deardorff
- Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California at Berkeley, Berkeley, CA, United States
| | - Robert B Gunier
- Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California at Berkeley, Berkeley, CA, United States
| | - Ana M Mora
- Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California at Berkeley, Berkeley, CA, United States
| | - Katherine Kogut
- Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California at Berkeley, Berkeley, CA, United States
| | - Sharon K Sagiv
- Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California at Berkeley, Berkeley, CA, United States; Division of Epidemiology, School of Public Health, University of California, Berkeley, Berkeley, CA, United States
| | - Asa Bradman
- Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California at Berkeley, Berkeley, CA, United States; Department of Public Health, School of Social Sciences, Humanities, and Arts, University of California, Merced, United States
| | - Brenda Eskenazi
- Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California at Berkeley, Berkeley, CA, United States.
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Maidoumi S, Ouaziz CR, Ouisselsat M, El Maouaki A, Loukid M, Lekouch N, Pineau A, Ahami A, Sedki A. Iron deficiency and cognitive impairment in children with low blood lead levels. Toxicol Rep 2022; 9:1681-1690. [DOI: 10.1016/j.toxrep.2022.08.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Revised: 08/09/2022] [Accepted: 08/19/2022] [Indexed: 11/28/2022] Open
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Gade M, Comfort N, Re DB. Sex-specific neurotoxic effects of heavy metal pollutants: Epidemiological, experimental evidence and candidate mechanisms. ENVIRONMENTAL RESEARCH 2021; 201:111558. [PMID: 34224706 PMCID: PMC8478794 DOI: 10.1016/j.envres.2021.111558] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 05/14/2021] [Accepted: 06/17/2021] [Indexed: 05/19/2023]
Abstract
The heavy metals lead (Pb), mercury (Hg), and cadmium (Cd) are ubiquitous environmental pollutants and are known to exert severe adverse impacts on the nervous system even at low concentrations. In contrast, the heavy metal manganese (Mn) is first and foremost an essential nutrient, but it becomes neurotoxic at high levels. Neurotoxic metals also include the less prevalent metalloid arsenic (As) which is found in excessive concentrations in drinking water and food sources in many regions of the world. Males and females often differ in how they respond to environmental exposures and adverse effects on their nervous systems are no exception. Here, we review the different types of sex-specific neurotoxic effects, such as cognitive and motor impairments, that have been attributed to Pb, Hg, Mn, Cd, and As exposure throughout the life course in epidemiological as well as in experimental toxicological studies. We also discuss differential vulnerability to these metals such as distinctions in behaviors and occupations across the sexes. Finally, we explore the different mechanisms hypothesized to account for sex-based differential susceptibility including hormonal, genetic, metabolic, anatomical, neurochemical, and epigenetic perturbations. An understanding of the sex-specific effects of environmental heavy metal neurotoxicity can aid in the development of more efficient systematic approaches in risk assessment and better exposure mitigation strategies with regard to sex-linked susceptibilities and vulnerabilities.
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Affiliation(s)
- Meethila Gade
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Nicole Comfort
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Diane B Re
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, USA; NIEHS Center of Northern Manhattan, Columbia University, New York, NY, USA; Motor Neuron Center for Biology and Disease, Columbia University, New York, NY, USA.
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10
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Green R, Rubenstein J, Popoli R, Capulong R, Till C. Sex-specific neurotoxic effects of early-life exposure to fluoride: A review of the epidemiologic and animal literature. CURR EPIDEMIOL REP 2020; 7:263-273. [PMID: 33816056 PMCID: PMC8011433 DOI: 10.1007/s40471-020-00246-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2020] [Indexed: 12/13/2022]
Abstract
PURPOSE OF REVIEW A growing body of evidence suggests adverse neurodevelopmental effects of early-life exposure to fluoride that may differ depending on timing of exposure and sex of the exposed. We conducted a literature search to identify the animal and human epidemiologic studies that examined sex-specific neurodevelopmental differences in response to prenatal and postnatal exposure to fluoride. RECENT FINDINGS Six of 138 animal studies and 15 of 106 human epidemiologic studies tested for sex-specific effects. Prenatal exposure to fluoride was associated with a male susceptibility to adverse behavioural effects in four of six animal studies and lower IQ in one of three prospective cohort studies. The body of evidence examining sex-effects associated with postnatal fluoride exposure was scarce, and many animal and cross-sectional human studies were considered to have a high risk of bias. SUMMARY Compared to females, male offspring appear to be more sensitive to prenatal, but not postnatal, exposure to fluoride. We discuss several sex-specific mechanisms and emphasize the need for future research.
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Affiliation(s)
- R. Green
- York University, Department of Psychology, 4700 Keele St
| | - J. Rubenstein
- York University, Department of Psychology, 4700 Keele St
| | - R. Popoli
- York University, Department of Psychology, 4700 Keele St
| | - R. Capulong
- York University, Department of Psychology, 4700 Keele St
| | - C. Till
- York University, Department of Psychology, 4700 Keele St
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Earl R, Burns N, Nettelbeck T, Baghurst P. Low‐level environmental lead exposure still negatively associated with children's cognitive abilities. AUSTRALIAN JOURNAL OF PSYCHOLOGY 2020. [DOI: 10.1111/ajpy.12096] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Rachel Earl
- School of Psychology, University of Adelaide, Adelaide, South Australia, Australia,
| | - Nicholas Burns
- School of Psychology, University of Adelaide, Adelaide, South Australia, Australia,
| | - Ted Nettelbeck
- School of Psychology, University of Adelaide, Adelaide, South Australia, Australia,
| | - Peter Baghurst
- School of Population Health, University of Adelaide, Adelaide, South Australia, Australia,
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Zhu YD, Wu XY, Yan SQ, Huang K, Tong J, Gao H, Xie Y, Tao SM, Ding P, Zhu P, Tao FB. Domain- and trimester-specific effect of prenatal phthalate exposure on preschooler cognitive development in the Ma'anshan Birth Cohort (MABC) study. ENVIRONMENT INTERNATIONAL 2020; 142:105882. [PMID: 32593839 DOI: 10.1016/j.envint.2020.105882] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 05/07/2020] [Accepted: 06/10/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Phthalates are a group of heavily produced endocrine disruptors that are widely used in personal care products, food packaging, building materials, and medical device. Few epidemiological studies have examined the effect of repeated prenatal exposure to multiple phthalates on preschooler cognitive development. OBJECTIVES This study aimed to examine the association between prenatal phthalate exposure measured at multiple time points and the intelligent quotient (IQ) scores of preschoolers, and to further identify the critical windows and specific intelligence domains in which phthalate exposure would affect preschooler cognitive development. METHODS The current study was based on the Ma'anshan Birth Cohort (MABC) study. Seven phthalate metabolites were measured in 2128 maternal urine samples collected during the first, second, and third trimesters of pregnancy. The IQ score of preschool-aged children were assessed with the Chinese version of the Wechsler Preschool and Primary Scale of Intelligence, Fourth edition (WPPSI-Ⅳ CN). Linear mixed models (LMMs) were used to assess the longitudinal effects of repeated prenatal phthalate exposure on children's IQ score. Multiple linear regression models were fitted to determine whether critical window phthalate exposure would affect cognitive development of children. RESULTS Overall, the repeated measures analysis indicated that the verbal comprehension index (VCI), visual space index (VSI) and full-scale intelligence quotient (FSIQ) decreased by 0.30 (95% CI: -0.60, 0; p = 0.05), 0.32 (95% CI: -0.62, -0.01; p = 0.04), and 0.31 (95% CI:-0.57, -0.04; p = 0.02) points, respectively, with each ln-transformed increase in the metabolite concentration of MBP. The fluid reasoning index (FRI) and processing speed index (PSI) increased by 0.30 (95% CI: 0.07, 0.54; p = 0.01) and 0.28 (95% CI: 0.06, 0.51; p = 0.01) points, respectively, with each ln-concentration increase in MEP. Trimester-specific regression models stratified by the sample collection time during pregnancy generated consistent results. In the first trimester, each ln-transformed MBP increase was associated with reductions in VCI, VSI and FSIQ of 0.56 (95% CI:-1.09, -0.02; p = 0.04), 0.60 (95% CI:-1.15, -0.05; p = 0.03) and 0.49 (95% CI:-0.97, -0.01; p = 0.04) points, respectively. In the third trimester, we observed that only MBzP exposure was associated with an increase in VCI (β: 0.48, 95% CI: 0.03, 0.92; p = 0.04). The gender-stratified analyses revealed that boys drove these associations. CONCLUSIONS Our results suggest that prenatal phthalate exposure impairs the cognitive development of preschoolers. The first trimester of pregnancy might be the most vulnerable period in terms of neurotoxicitydue to phthalate exposure. These findings warrant further confirmation.
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Affiliation(s)
- Yuan-Duo Zhu
- Department of Maternal, Child and Adolescent Health, School of Public Health, Anhui Medical University, No 81 Meishan Road, Hefei 230032, Anhui, China; MOE Key Laboratory of Population Health Across Life Cycle, No 81 Meishan Road, Hefei 230032, Anhui, China; NHC Key Laboratory of Study on Abnormal Gametes and Reproductive Tract, No 81 Meishan Road, Hefei 230032, Anhui, China; Anhui Provincial Key Laboratory of Population Health and Aristogenics, Anhui Medical University, No 81 Meishan Road, Hefei 230032, Anhui, China
| | - Xiao-Yan Wu
- Department of Maternal, Child and Adolescent Health, School of Public Health, Anhui Medical University, No 81 Meishan Road, Hefei 230032, Anhui, China; MOE Key Laboratory of Population Health Across Life Cycle, No 81 Meishan Road, Hefei 230032, Anhui, China; NHC Key Laboratory of Study on Abnormal Gametes and Reproductive Tract, No 81 Meishan Road, Hefei 230032, Anhui, China; Anhui Provincial Key Laboratory of Population Health and Aristogenics, Anhui Medical University, No 81 Meishan Road, Hefei 230032, Anhui, China
| | - Shuang-Qin Yan
- Ma'anshan Maternal and Child Healthcare (MCH) Center, Ma'anshan 243011, China
| | - Kun Huang
- Department of Maternal, Child and Adolescent Health, School of Public Health, Anhui Medical University, No 81 Meishan Road, Hefei 230032, Anhui, China; MOE Key Laboratory of Population Health Across Life Cycle, No 81 Meishan Road, Hefei 230032, Anhui, China; NHC Key Laboratory of Study on Abnormal Gametes and Reproductive Tract, No 81 Meishan Road, Hefei 230032, Anhui, China; Anhui Provincial Key Laboratory of Population Health and Aristogenics, Anhui Medical University, No 81 Meishan Road, Hefei 230032, Anhui, China
| | - Juan Tong
- Department of Maternal, Child and Adolescent Health, School of Public Health, Anhui Medical University, No 81 Meishan Road, Hefei 230032, Anhui, China; MOE Key Laboratory of Population Health Across Life Cycle, No 81 Meishan Road, Hefei 230032, Anhui, China; NHC Key Laboratory of Study on Abnormal Gametes and Reproductive Tract, No 81 Meishan Road, Hefei 230032, Anhui, China; Anhui Provincial Key Laboratory of Population Health and Aristogenics, Anhui Medical University, No 81 Meishan Road, Hefei 230032, Anhui, China
| | - Hui Gao
- MOE Key Laboratory of Population Health Across Life Cycle, No 81 Meishan Road, Hefei 230032, Anhui, China; NHC Key Laboratory of Study on Abnormal Gametes and Reproductive Tract, No 81 Meishan Road, Hefei 230032, Anhui, China; Anhui Provincial Key Laboratory of Population Health and Aristogenics, Anhui Medical University, No 81 Meishan Road, Hefei 230032, Anhui, China
| | - Yang Xie
- Department of Maternal, Child and Adolescent Health, School of Public Health, Anhui Medical University, No 81 Meishan Road, Hefei 230032, Anhui, China; MOE Key Laboratory of Population Health Across Life Cycle, No 81 Meishan Road, Hefei 230032, Anhui, China; NHC Key Laboratory of Study on Abnormal Gametes and Reproductive Tract, No 81 Meishan Road, Hefei 230032, Anhui, China; Anhui Provincial Key Laboratory of Population Health and Aristogenics, Anhui Medical University, No 81 Meishan Road, Hefei 230032, Anhui, China
| | - Shu-Man Tao
- MOE Key Laboratory of Population Health Across Life Cycle, No 81 Meishan Road, Hefei 230032, Anhui, China; NHC Key Laboratory of Study on Abnormal Gametes and Reproductive Tract, No 81 Meishan Road, Hefei 230032, Anhui, China; Anhui Provincial Key Laboratory of Population Health and Aristogenics, Anhui Medical University, No 81 Meishan Road, Hefei 230032, Anhui, China
| | - Peng Ding
- Department of Maternal, Child and Adolescent Health, School of Public Health, Anhui Medical University, No 81 Meishan Road, Hefei 230032, Anhui, China; MOE Key Laboratory of Population Health Across Life Cycle, No 81 Meishan Road, Hefei 230032, Anhui, China; NHC Key Laboratory of Study on Abnormal Gametes and Reproductive Tract, No 81 Meishan Road, Hefei 230032, Anhui, China; Anhui Provincial Key Laboratory of Population Health and Aristogenics, Anhui Medical University, No 81 Meishan Road, Hefei 230032, Anhui, China
| | - Peng Zhu
- Department of Maternal, Child and Adolescent Health, School of Public Health, Anhui Medical University, No 81 Meishan Road, Hefei 230032, Anhui, China; MOE Key Laboratory of Population Health Across Life Cycle, No 81 Meishan Road, Hefei 230032, Anhui, China; NHC Key Laboratory of Study on Abnormal Gametes and Reproductive Tract, No 81 Meishan Road, Hefei 230032, Anhui, China; Anhui Provincial Key Laboratory of Population Health and Aristogenics, Anhui Medical University, No 81 Meishan Road, Hefei 230032, Anhui, China
| | - Fang-Biao Tao
- Department of Maternal, Child and Adolescent Health, School of Public Health, Anhui Medical University, No 81 Meishan Road, Hefei 230032, Anhui, China; MOE Key Laboratory of Population Health Across Life Cycle, No 81 Meishan Road, Hefei 230032, Anhui, China; NHC Key Laboratory of Study on Abnormal Gametes and Reproductive Tract, No 81 Meishan Road, Hefei 230032, Anhui, China; Anhui Provincial Key Laboratory of Population Health and Aristogenics, Anhui Medical University, No 81 Meishan Road, Hefei 230032, Anhui, China.
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Meyers AL, Woodbury MP, Nelson RA. Orthopedic Manifestations of Lead Toxicity. Orthopedics 2020; 43:e202-e207. [PMID: 32324246 DOI: 10.3928/01477447-20200415-06] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 05/21/2019] [Indexed: 02/03/2023]
Abstract
Given the recent news regarding the water supply in Flint, Michigan, lead toxicity has become an increasingly important topic in health care. Lead toxicity can have a widespread effect on the human body. Because lead has a significant effect on mineralized tissue such as bone, the purpose of this review was to identify and analyze the orthopedic manifestations of lead poisoning. The effects of lead at the cellular level, on the hematopoietic system, in osteoporosis, and in pediatric patients are discussed. Possible treatment options and recommendations for further monitoring are presented. [Orthopedics. 2020;43(4):e202-e207.].
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Evidence for interaction between genetic liability and childhood trauma in the development of psychotic symptoms. Soc Psychiatry Psychiatr Epidemiol 2019; 54:1045-1054. [PMID: 31209522 DOI: 10.1007/s00127-019-01711-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 04/08/2019] [Indexed: 10/26/2022]
Abstract
PURPOSE Whilst childhood trauma (CT) is a known risk factor across the spectrum of psychosis expression, little is known about possible interplay with genetic liability. METHODS The TwinssCan Study collected data in general population twins, focussing on expression of psychosis at the level of subthreshold psychotic experiences. A multilevel mixed-effects linear regression analysis was performed including 745 subjects to assess the interaction between genetic liability and CT. The Symptom Checklist-90 (SCL-90-R) score of the co-twin was used as an indirect measure of genetic liability to psychopathology, while the Childhood Trauma Questionnaire Short-Form (CTQ-SF) was used to assess CT in the domains of physical, emotional and sexual abuse, as well as physical and emotional neglect. The Community Assessment of Psychic Experience (CAPE) questionnaire was used to phenotypically characterize psychosis expression. RESULTS In the model using the CAPE total score, the interaction between CT and genetic liability was close to statistical significance (χ2 = 5.6, df = 2, p = 0.06). Analyses of CAPE subscales revealed a significant interaction between CT and genetic liability (χ2 = 8.8, df = 2, p = 0.012) for the CAPE-negative symptoms subscale, but not for the other two subscales (i.e. positive and depressive). CONCLUSION The results suggest that the impact of CT on subthreshold expression of psychosis, particularly in the negative subdomain, may be larger in the co-presence of significant genetic liability for psychopathology.
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Abstract
Millions of Americans now entering midlife and old age were exposed to high levels of lead, a neurotoxin, as children. Evidence from animal-model and human observational studies suggest that childhood lead exposure may raise the risk of adult neurodegenerative disease, particularly dementia, through a variety of possible mechanisms including epigenetic modification, delayed cardiovascular and kidney disease, direct degenerative CNS injury from lead remobilized from bone, and lowered neural and cognitive reserve. Within the next ten years, the generation of children with the highest historical lead exposures, those born in the 1960s, 1970s, and 1980s, will begin to enter the age at which dementia symptoms tend to emerge. Many will also enter the age in which lead stored in the skeleton may be remobilized at greater rates, particularly for women entering menopause and men and women experiencing osteoporosis. Should childhood lead exposure prove pro-degenerative, the next twenty years will provide the last opportunities for possible early intervention to forestall greater degenerative disease burden across the aging lead-exposed population. More evidence is needed now to characterize the nature and magnitude of the degenerative risks facing adults exposed to lead as children and to identify interventions to limit long-term harm.
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Affiliation(s)
- Aaron Reuben
- Department of Psychology and Neuroscience, Duke University, Durham, NC, USA
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16
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Perera FP, Wheelock K, Wang Y, Tang D, Margolis AE, Badia G, Cowell W, Miller RL, Rauh V, Wang S, Herbstman JB. Combined effects of prenatal exposure to polycyclic aromatic hydrocarbons and material hardship on child ADHD behavior problems. ENVIRONMENTAL RESEARCH 2018; 160:506-513. [PMID: 28987706 PMCID: PMC5724364 DOI: 10.1016/j.envres.2017.09.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 08/28/2017] [Accepted: 09/07/2017] [Indexed: 05/22/2023]
Abstract
IMPORTANCE Polycyclic aromatic hydrocarbons (PAH) are carcinogenic and neurotoxic combustion by-products commonly found in urban air. Exposure to PAH is disproportionately high in low income communities of color who also experience chronic economic stress. OBJECTIVE In a prospective cohort study in New York City (NYC) we previously found a significant association between prenatal PAH exposure and Attention Deficit Hyperactivity Disorder (ADHD) behavior problems at age 9. Here, we have evaluated the joint effects of prenatal exposure to PAH and prenatal/childhood material hardship on ADHD behavior problems. MATERIALS AND METHODS We enrolled nonsmoking African-American and Dominican pregnant women in New York City between 1998 and 2006 and followed their children through 9 years of age. As a biomarker of prenatal PAH exposure, PAH-DNA adducts were measured in maternal blood at delivery and were dichotomized at the limit of detection (to indicate high vs. low exposure). Maternal material hardship (lack of adequate food, housing, utilities, and clothing) was self-reported prenatally and at multiple time points through child age 9. Latent variable analysis identified four distinct patterns of hardship. ADHD behavior problems were assessed using the Conners Parent Rating Scale- Revised. Analyses adjusted for relevant covariates. RESULTS Among 351 children in our sample, across all hardship groups, children with high prenatal PAH exposure (high adducts) generally had more symptoms of ADHD (higher scores) compared to those with low PAH exposure. The greatest difference was seen among the children with hardship persisting from pregnancy through childhood. Although the interactions between high PAH exposure and hardship experienced at either period ("persistent" hardship or "any" hardship) were not significant, we observed significant differences in the number of ADHD symptoms between children with high prenatal PAH exposure and either persistent hardship or any hardship compared to the others. These differences were most significant for combined high PAH and persistent hardship: ADHD Index (p < 0.008), DSM-IV Inattentive (p = 0.006), DSM-IV Hyperactive Impulsive problems (p = 0.033), and DSM-IV Index Total (p = 0.009). CONCLUSION The present findings add to existing evidence that co-exposure to socioeconomic disadvantage and air pollution in early life significantly increases the risk of adverse neurodevelopmental outcomes. They suggest the need for multifaceted interventions to protect pregnant mothers and their children.
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Affiliation(s)
- Frederica P Perera
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, 722W. 168th Street, New York, NY 10032, USA; Columbia Center for Children's Environmental Health, Mailman School of Public Health, Columbia University, 722W. 168th Street, New York, NY 10032, USA.
| | - Kylie Wheelock
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, 722W. 168th Street, New York, NY 10032, USA; Columbia Center for Children's Environmental Health, Mailman School of Public Health, Columbia University, 722W. 168th Street, New York, NY 10032, USA.
| | - Ya Wang
- Columbia Center for Children's Environmental Health, Mailman School of Public Health, Columbia University, 722W. 168th Street, New York, NY 10032, USA; Department of Biostatistics, Mailman School of Public Health, Columbia University, 722W. 168th Street, New York, NY 10032, USA.
| | - Deliang Tang
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, 722W. 168th Street, New York, NY 10032, USA; Columbia Center for Children's Environmental Health, Mailman School of Public Health, Columbia University, 722W. 168th Street, New York, NY 10032, USA.
| | - Amy E Margolis
- Columbia Center for Children's Environmental Health, Mailman School of Public Health, Columbia University, 722W. 168th Street, New York, NY 10032, USA; The Heilbrunn Center for Population and Family Health, Mailman School of Public Health, Columbia University, 60 Haven Avenue, New York, NY 10032, USA.
| | - Gladys Badia
- Columbia Center for Children's Environmental Health, Mailman School of Public Health, Columbia University, 722W. 168th Street, New York, NY 10032, USA.
| | - Whitney Cowell
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, 722W. 168th Street, New York, NY 10032, USA.
| | - Rachel L Miller
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, 722W. 168th Street, New York, NY 10032, USA; Columbia Center for Children's Environmental Health, Mailman School of Public Health, Columbia University, 722W. 168th Street, New York, NY 10032, USA; Division of Child & Adolescent Psychiatry and the Center for Developmental Neuropsychiatry, Department of Psychiatry, the New York State Psychiatric Institute and the College of Physicians and Surgeons, Columbia University, New York, NY, USA; Division of Pulmonary, Allergy and Critical Care of Medicine, Department of Medicine, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, New York, NY 10032, USA.
| | - Virginia Rauh
- Columbia Center for Children's Environmental Health, Mailman School of Public Health, Columbia University, 722W. 168th Street, New York, NY 10032, USA; Division of Pediatric Allergy, Immunology and Rheumatology, Department of Pediatrics, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, New York, New York 10032, USA.
| | - Shuang Wang
- Columbia Center for Children's Environmental Health, Mailman School of Public Health, Columbia University, 722W. 168th Street, New York, NY 10032, USA; Department of Biostatistics, Mailman School of Public Health, Columbia University, 722W. 168th Street, New York, NY 10032, USA.
| | - Julie B Herbstman
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, 722W. 168th Street, New York, NY 10032, USA; Columbia Center for Children's Environmental Health, Mailman School of Public Health, Columbia University, 722W. 168th Street, New York, NY 10032, USA.
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Tassiopoulos K, Huo Y, Braun J, Williams PL, Smith R, Aschengrau A, Nichols S, Hazra R, Meyer WA, Knapp K, Deygoo NS, Seage GR, for the Pediatric HIV/AIDS Cohort S. Blood lead levels and neurodevelopmental function in perinatally HIV-exposed, uninfected children in a US-based longitudinal cohort study. AIDS Res Hum Retroviruses 2017; 33:919-928. [PMID: 28322573 DOI: 10.1089/aid.2016.0265] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND While children's exposure to environmental lead in the U.S. has decreased, areas of elevated levels remain. Because lead exposure is a risk factor for developmental delays, it should be considered when studying neurodevelopmental effects of in-utero antiretroviral medication (ARV) exposure in the growing population of perinatally HIV-exposed, uninfected children (PHEU). We compared blood lead levels (BPb) in PHEU children enrolled in the Surveillance Monitoring of ART Toxicities (SMARTT) Study to U.S. children, assessed associations with neurodevelopment, and explored whether associations between in-utero ARV and neurodevelopment are modified by BPb. METHODS Prevalence of elevated BPb (≥5 µg/dL) at ages 1-2 years was calculated by year and race/ethnicity and compared to that for children in the National Health and Nutrition Examination Survey (NHANES 2002-2010). Associations between elevated BPb and neurodevelopment at 1 and 3 years were assessed. Associations between ARVs (tenofovir disopropil fumarate [TDF]; atazanavir) and neurodevelopment were evaluated within BPb level (≥5 vs. <5 µg/dL). RESULTS Mean BPb in SMARTT decreased from 5.9 to 2.7 µg/dL between 1998-2014; prevalence of elevated BPb decreased from 50% to 4%. Both were consistently higher than in NHANES. Elevated BPb was associated with cognitive delay at age 3 (adjusted odds ratio: 1.64; 95% CI: 0.95, 2.90). At age 1, TDF was associated with delay only among those with elevated BPb. CONCLUSIONS PHEU children more often had elevated BPb than the general U.S. pediatric population. Exposure to environmental lead is one of several factors that may place these children at higher risk for neurodevelopmental delay.
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Affiliation(s)
- Katherine Tassiopoulos
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - Yanling Huo
- Center for Biostatistics in AIDS Research, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - Joseph Braun
- Department of Epidemiology, Brown University, Providence, Rhode Island
| | - Paige L. Williams
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - Renee Smith
- Department of Pediatrics, University of Illinois, Chicago, Illinois
| | - Ann Aschengrau
- Department of Epidemiology, Boston University School of Public Health, Boston, Massachusetts
| | - Sharon Nichols
- Department of Neurosciences, University of California, San Diego, California
| | - Rohan Hazra
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | | | - Katherine Knapp
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Nagamah S. Deygoo
- Department of Pediatrics, NYU School of Medicine, New York, New York
| | - George R. Seage
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
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Prenatal maternal stress in relation to the effects of prenatal lead exposure on toddler cognitive development. Neurotoxicology 2017; 59:71-78. [DOI: 10.1016/j.neuro.2017.01.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 01/25/2017] [Accepted: 01/27/2017] [Indexed: 12/21/2022]
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Sanchez OF, Lee J, Yu King Hing N, Kim SE, Freeman JL, Yuan C. Lead (Pb) exposure reduces global DNA methylation level by non-competitive inhibition and alteration of dnmt expression. Metallomics 2017; 9:149-160. [DOI: 10.1039/c6mt00198j] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Bellinger DC, Matthews-Bellinger JA, Kordas K. A developmental perspective on early-life exposure to neurotoxicants. ENVIRONMENT INTERNATIONAL 2016; 94:103-112. [PMID: 27235688 DOI: 10.1016/j.envint.2016.05.014] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 05/14/2016] [Accepted: 05/14/2016] [Indexed: 05/24/2023]
Abstract
BACKGROUND Studies of early-life neurotoxicant exposure have not been designed, analyzed, or interpreted in the context of a fully developmental perspective. OBJECTIVES The goal of this paper is to describe the key principles of a developmental perspective and to use examples from the literature to illustrate the relevance of these principles to early-life neurotoxicant exposures. METHODS Four principles are discussed: 1) the effects of early-life neurotoxicant exposure depend on a child's developmental context; 2) deficits caused by early-life exposure initiate developmental cascades that can lead to pathologies that differ from those observed initially; 3) early-life neurotoxicant exposure has intra-familial and intergenerational impacts; 4) the impacts of early-life neurotoxicant exposure influence a child's ability to respond to future insults. The first principle is supported by considerable evidence, but the other three have received much less attention. DISCUSSION Incorporating a developmental perspective in studies of early-life neurotoxicant exposures requires prospective collection of data on a larger array of covariates than usually considered, using analytical approaches that acknowledge the transactional processes between a child and the environment and the phenomenon of developmental cascades. CONCLUSION Consideration of early-life neurotoxicant exposure within a developmental perspective reveals that many issues remain to be explicated if we are to achieve a deep understanding of the societal health burden associated with early-life neurotoxicant exposures.
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Affiliation(s)
- David C Bellinger
- Department of Neurology, Harvard Medical School, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02112, USA; Department of Psychiatry, Harvard Medical School, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA.
| | - Julia A Matthews-Bellinger
- Department of Psychiatry, University of Massachusetts Medical School, Boston Psychoanalytic Society and Institute, 19 Fair Oaks Park, Needham, MA 02492, USA.
| | - Katarzyna Kordas
- Department of Epidemiology and Environmental Health, University at Buffalo, 270 Farber Hall, Buffalo, NY 14214, USA.
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Hubbs-Tait L, Nation JR, Krebs NF, Bellinger DC. Neurotoxicants, Micronutrients, and Social Environments. Psychol Sci Public Interest 2016; 6:57-121. [DOI: 10.1111/j.1529-1006.2005.00024.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
SUMMARY—Systematic research evaluating the separate and interacting impacts of neurotoxicants, micronutrients, and social environments on children's cognition and behavior has only recently been initiated. Years of extensive human epidemiologic and animal experimental research document the deleterious impact of lead and other metals on the nervous system. However, discrepancies among human studies and between animal and human studies underscore the importance of variations in child nutrition as well as social and behavioral aspects of children's environments that mitigate or exacerbate the effects of neurotoxicants. In this monograph, we review existing research on the impact of neurotoxic metals, nutrients, and social environments and interactions across the three domains. We examine the literature on lead, mercury, manganese, and cadmium in terms of dispersal, epidemiology, experimental animal studies, effects of social environments, and effects of nutrition. Research documenting the negative impact of lead on cognition and behavior influenced reductions by the Center for Disease Control in child lead-screening guidelines from 30 micrograms per deciliter (μg/dL) in 1975 to 25 μg/dL in 1985 and to 10 μg/dL in 1991. A further reduction is currently being considered. Experimental animal research documents lead's alteration of glutamate-neurotransmitter (particularly N-methyl-D-aspartate) activity vital to learning and memory. In addition, lead induces changes in cholinergic and dopaminergic activity. Elevated lead concentrations in the blood are more common among children living in poverty and there is some evidence that socioeconomic status influences associations between lead and child outcomes. Micronutrients that influence the effects of lead include iron and zinc. Research documenting the negative impact of mercury on children (as well as adults) has resulted in a reference dose (RfD) of 0.1 microgram per kilogram of body weight per day (μg/kg/day). In animal studies, mercury interferes with glutamatergic, cholinergic, and dopaminergic activity. Although evidence for interactions of mercury with children's social contexts is minimal, researchers are examining interactions of mercury with several nutrients. Research on the effects of cadmium and manganese on child cognition and behavior is just beginning. Experimental animal research links cadmium to learning deficits, manganese to behaviors characteristic of Parkinson's disease, and both to altered dopaminergic functioning. We close our review with a discussion of policy implications, and we recommend interdisciplinary research that will enable us to bridge gaps within and across domains.
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Affiliation(s)
- Laura Hubbs-Tait
- Department of Human Development and Family Science, Oklahoma State University
| | | | - Nancy F. Krebs
- Department of Pediatrics, University of Colorado School of Medicine
| | - David C. Bellinger
- Department of Neurology, Harvard Medical School; Department of Environmental Health, Harvard School of Public Health; and Children's Hospital Boston
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Sun S, Cao P, Chan KP, Tsang H, Wong CM, Thach TQ. Temperature as a modifier of the effects of fine particulate matter on acute mortality in Hong Kong. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2015; 205:357-364. [PMID: 26123725 DOI: 10.1016/j.envpol.2015.06.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 06/03/2015] [Accepted: 06/08/2015] [Indexed: 06/04/2023]
Abstract
Interactions between particulate matter with aerodynamic diameter less than or equal to 2.5 μm (PM2.5) and temperature on mortality have not been well studied, and results are difficult to synthesize. We aimed to assess modification of temperature on the association between PM2.5 and cause-specific mortality by stratifying temperature into low, medium, and high stratum in Hong Kong, using data from 1999 to 2011. The mortality effects of PM2.5 were stronger in low temperature stratum than those in high. The excess risk (%) per 10 μg/m(3) increase in PM2.5 at lag 0-1 in low temperature stratum were 0.94% (95% confidence interval: 0.65, 1.24) for all natural, 0.88% (0.38, 1.37) for cardiovascular, and 1.15% (0.51, 1.79) for respiratory mortality. We found statistically significant interaction of PM2.5 and temperature between low and high temperature stratum for all natural mortality. Our results suggested that temperature might modify mortality effects of PM2.5 in Hong Kong.
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Affiliation(s)
- Shengzhi Sun
- School of Public Health, The University of Hong Kong, Hong Kong SAR, China
| | - Peihua Cao
- School of Public Health, The University of Hong Kong, Hong Kong SAR, China
| | - King-Pan Chan
- School of Public Health, The University of Hong Kong, Hong Kong SAR, China
| | - Hilda Tsang
- School of Public Health, The University of Hong Kong, Hong Kong SAR, China
| | - Chit-Ming Wong
- School of Public Health, The University of Hong Kong, Hong Kong SAR, China
| | - Thuan-Quoc Thach
- School of Public Health, The University of Hong Kong, Hong Kong SAR, China.
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Xu J, Hu H, Wright R, Sánchez BN, Schnaas L, Bellinger DC, Park SK, Martínez S, Hernández-Avila M, Téllez-Rojo MM, Wright RO. Prenatal Lead Exposure Modifies the Impact of Maternal Self-Esteem on Children's Inattention Behavior. J Pediatr 2015; 167:435-41. [PMID: 26047683 PMCID: PMC4692471 DOI: 10.1016/j.jpeds.2015.04.057] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 04/02/2015] [Accepted: 04/22/2015] [Indexed: 11/22/2022]
Abstract
OBJECTIVE To prospectively evaluate the association of maternal self-esteem measured when their offspring were toddlers with the subsequent development of attention deficit hyperactivity disorder (ADHD)-like behavior in their school-age offspring and the potential modifying effects of prenatal lead exposure. STUDY DESIGN We evaluated a subsample of 192 mother-child pairs from a long-running birth-cohort project that enrolled mothers in Mexico from 1994-2011. Prenatal lead exposure was assessed using cord blood lead and maternal bone lead around delivery (tibia and patella lead, measured by K-x-ray-fluorescence). When children were 2 years old, maternal self-esteem was measured using the Coopersmith Self-Esteem Inventory. When children were 7-15 years old, children's blood lead levels and ADHD symptoms were assessed, and Conners' Parent Rating Scale-Revised and Behavior Rating Inventory of Executive Function-Parent Form were used as measures of ADHD-like behavior. RESULTS Adjusting for family economic status, marital status, maternal education and age, child's age and sex, and children's current blood lead levels, increased maternal self-esteem was associated with reduced child inattention behavior. Compared with those among high prenatal lead exposure (P25-P100), this association was stronger among low prenatal lead exposure groups (P1-P25, P values for the interaction effects between prenatal lead exposure and maternal self-esteem levels of <.10). Each 1-point increase in maternal self-esteem scores was associated with 0.6- to 1.3-point decrease in Conners' Parent Rating Scale-Revised and Behavior Rating Inventory of Executive Function-Parent Form T-scores among groups with low cord blood lead and patella lead (P1-P25). CONCLUSIONS Children experiencing high maternal self-esteem during toddlerhood were less likely to develop inattention behavior at school age. Prenatal lead exposure may play a role in attenuating this protective effect.
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Affiliation(s)
- Jian Xu
- Xinhua Hospital, MOE-Shanghai Key Laboratory of Children's Environmental Health, Department of Child and Adolescent Healthcare, Shanghai Institute for Pediatric Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Howard Hu
- Dalla Lana School of Public Health, University of Toronto, Ontario, Canada; Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI.
| | - Rosalind Wright
- Kravis Children's Hospital, Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY; Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Brisa N Sánchez
- Department of Biostatistics, University of Michigan School of Public Health, Ann Arbor, MI
| | | | | | - Sung Kyun Park
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI; Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, MI
| | | | | | | | - Robert O Wright
- Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY; Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, NY
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Skerfving S, Löfmark L, Lundh T, Mikoczy Z, Strömberg U. Late effects of low blood lead concentrations in children on school performance and cognitive functions. Neurotoxicology 2015; 49:114-20. [DOI: 10.1016/j.neuro.2015.05.009] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 05/22/2015] [Accepted: 05/23/2015] [Indexed: 12/01/2022]
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Goodman JE, Petito Boyce C, Sax SN, Beyer LA, Prueitt RL. Rethinking Meta-Analysis: Applications for Air Pollution Data and Beyond. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2015; 35:1017-39. [PMID: 25969128 PMCID: PMC4690509 DOI: 10.1111/risa.12405] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Meta-analyses offer a rigorous and transparent systematic framework for synthesizing data that can be used for a wide range of research areas, study designs, and data types. Both the outcome of meta-analyses and the meta-analysis process itself can yield useful insights for answering scientific questions and making policy decisions. Development of the National Ambient Air Quality Standards illustrates many potential applications of meta-analysis. These applications demonstrate the strengths and limitations of meta-analysis, issues that arise in various data realms, how meta-analysis design choices can influence interpretation of results, and how meta-analysis can be used to address bias and heterogeneity. Reviewing available data from a meta-analysis perspective can provide a useful framework and impetus for identifying and refining strategies for future research. Moreover, increased pervasiveness of a meta-analysis mindset-focusing on how the pieces of the research puzzle fit together-would benefit scientific research and data syntheses regardless of whether or not a quantitative meta-analysis is undertaken. While an individual meta-analysis can only synthesize studies addressing the same research question, the results of separate meta-analyses can be combined to address a question encompassing multiple data types. This observation applies to any scientific or policy area where information from a variety of disciplines must be considered to address a broader research question.
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Vishnevetsky J, Tang D, Chang HW, Roen EL, Wang Y, Rauh V, Wang S, Miller RL, Herbstman J, Perera FP. Combined effects of prenatal polycyclic aromatic hydrocarbons and material hardship on child IQ. Neurotoxicol Teratol 2015; 49:74-80. [PMID: 25912623 DOI: 10.1016/j.ntt.2015.04.002] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 02/20/2015] [Accepted: 04/15/2015] [Indexed: 01/09/2023]
Abstract
IMPORTANCE Polycyclic aromatic hydrocarbons are common carcinogenic and neurotoxic urban air pollutants. Toxic exposures, including air pollution, are disproportionately high in communities of color and frequently co-occur with chronic economic deprivation. OBJECTIVES We examined whether the association between child IQ and prenatal exposure to polycyclic aromatic hydrocarbons differed between groups of children whose mothers reported high vs. low material hardship during their pregnancy and through child age 5. We tested statistical interactions between hardships and polycyclic aromatic hydrocarbons, as measured by DNA adducts in cord blood, to determine whether material hardship exacerbated the association between adducts and IQ scores. DESIGN Prospective cohort. Participants were recruited from 1998 to 2006 and followed from gestation through age 7 years. SETTING Urban community (New York City) PARTICIPANTS A community-based sample of 276 minority urban youth EXPOSURE MEASURE: Polycyclic aromatic hydrocarbon-DNA adducts in cord blood as an individual biomarker of prenatal polycyclic aromatic hydrocarbon exposure. Maternal material hardship self-reported prenatally and at multiple timepoints through early childhood. MAIN OUTCOME MEASURE Child IQ at 7 years assessed using the Wechsler Intelligence Scale for Children. RESULTS Significant inverse effects of high cord PAH-DNA adducts on full scale IQ, perceptual reasoning and working memory scores were observed in the groups whose mothers reported a high level of material hardship during pregnancy or recurring high hardship into the child's early years, and not in those without reported high hardship. Significant interactions were observed between high cord adducts and prenatal hardship on working memory scores (β = -8.07, 95% CI (-14.48, -1.66)) and between high cord adducts and recurrent material hardship (β = -9.82, 95% CI (-16.22, -3.42)). CONCLUSION The findings add to other evidence that socioeconomic disadvantage can increase the adverse effects of toxic physical "stressors" like air pollutants. Observed associations between high cord adducts and reduced IQ were significant only among the group of children whose mothers reported high material hardship. These results indicate the need for a multifaceted approach to prevention.
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Affiliation(s)
- Julia Vishnevetsky
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, 722 W. 168th Street, New York, NY 10032, USA; Columbia Center for Children's Environmental Health, Mailman School of Public Health, Columbia University, 722 W. 168th Street, New York, NY 10032, USA
| | - Deliang Tang
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, 722 W. 168th Street, New York, NY 10032, USA; Columbia Center for Children's Environmental Health, Mailman School of Public Health, Columbia University, 722 W. 168th Street, New York, NY 10032, USA
| | - Hsin-Wen Chang
- Columbia Center for Children's Environmental Health, Mailman School of Public Health, Columbia University, 722 W. 168th Street, New York, NY 10032, USA; Department of Biostatistics, Mailman School of Public Health, Columbia University, 722 W. 168th Street, New York, NY 10032, USA
| | - Emily L Roen
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, 722 W. 168th Street, New York, NY 10032, USA; Columbia Center for Children's Environmental Health, Mailman School of Public Health, Columbia University, 722 W. 168th Street, New York, NY 10032, USA
| | - Ya Wang
- Columbia Center for Children's Environmental Health, Mailman School of Public Health, Columbia University, 722 W. 168th Street, New York, NY 10032, USA; Department of Biostatistics, Mailman School of Public Health, Columbia University, 722 W. 168th Street, New York, NY 10032, USA
| | - Virginia Rauh
- Columbia Center for Children's Environmental Health, Mailman School of Public Health, Columbia University, 722 W. 168th Street, New York, NY 10032, USA; The Heilbrunn Center for Population and Family Health, Mailman School of Public Health, Columbia University, 60 Haven Avenue, New York, NY 10032, USA
| | - Shuang Wang
- Columbia Center for Children's Environmental Health, Mailman School of Public Health, Columbia University, 722 W. 168th Street, New York, NY 10032, USA; Department of Biostatistics, Mailman School of Public Health, Columbia University, 722 W. 168th Street, New York, NY 10032, USA
| | - Rachel L Miller
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, 722 W. 168th Street, New York, NY 10032, USA; Columbia Center for Children's Environmental Health, Mailman School of Public Health, Columbia University, 722 W. 168th Street, New York, NY 10032, USA; Division of Pulmonary, Allergy and Critical Care of Medicine, Department of Medicine, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, New York, NY 10032, USA; Division of Pediatric Allergy, Immunology and Rheumatology, Department of Pediatrics, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, New York, NY 10032, USA
| | - Julie Herbstman
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, 722 W. 168th Street, New York, NY 10032, USA; Columbia Center for Children's Environmental Health, Mailman School of Public Health, Columbia University, 722 W. 168th Street, New York, NY 10032, USA
| | - Frederica P Perera
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, 722 W. 168th Street, New York, NY 10032, USA; Columbia Center for Children's Environmental Health, Mailman School of Public Health, Columbia University, 722 W. 168th Street, New York, NY 10032, USA.
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Love TM, Thurston SW, Davidson PW. Finding vulnerable subpopulations in the Seychelles Child Development Study: effect modification with latent groups. Stat Methods Med Res 2014; 26:809-822. [PMID: 25512145 DOI: 10.1177/0962280214560044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The Seychelles Child Development Study is a research project with the objective of examining associations between prenatal exposure to low doses of methylmercury from maternal fish consumption and children's developmental outcomes. Whether methylmercury has neurotoxic effects at low doses remains unclear and recommendations for pregnant women and children to reduce fish intake may prevent a substantial number of people from receiving sufficient nutrients that are abundant in fish. The primary findings of the Seychelles Child Development Study are inconsistent with adverse associations between methylmercury from fish consumption and neurodevelopmental outcomes. However, whether there are subpopulations of children who are particularly sensitive to this diet is an open question. Secondary analysis from this study found significant interactions between prenatal methylmercury levels and both caregiver IQ and income on 19-month IQ. These results are sensitive to the categories chosen for these covariates and are difficult to interpret collectively. In this paper, we estimate effect modification of the association between prenatal methylmercury exposure and 19-month IQ using a general formulation of mixture regression. Our mixture regression model creates a latent categorical group membership variable which interacts with methylmercury in predicting the outcome. We also fit the same outcome model when in addition the latent variable is assumed to be a parametric function of three distinct socioeconomic measures. Bayesian methods allow group membership and the regression coefficients to be estimated simultaneously and our approach yields a principled choice of the number of distinct subpopulations. The results show three groups with different response patterns between prenatal methylmercury exposure and 19-month IQ in this population.
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Affiliation(s)
- Tanzy Mt Love
- 1 Department of Biostatistics and Computational Biology, University of Rochester, Rochester, NY, USA
| | - Sally W Thurston
- 1 Department of Biostatistics and Computational Biology, University of Rochester, Rochester, NY, USA
| | - Philip W Davidson
- 2 Departments of Pediatrics, University of Rochester, Rochester, NY, USA
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28
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Perkins M, Wright RO, Amarasiriwardena CJ, Jayawardene I, Rifas-Shiman SL, Oken E. Very low maternal lead level in pregnancy and birth outcomes in an eastern Massachusetts population. Ann Epidemiol 2014; 24:915-9. [PMID: 25444892 PMCID: PMC4254591 DOI: 10.1016/j.annepidem.2014.09.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 08/30/2014] [Accepted: 09/16/2014] [Indexed: 12/30/2022]
Abstract
PURPOSE Maternal lead exposure is associated with poor birth outcomes in populations with moderate to high blood levels. However, no studies have looked at exposure levels commonly experienced by US women. METHODS We evaluated the relationship between maternal red blood cell (RBC) lead levels in midpregnancy and birth outcomes in 949 mother-child pairs in a prebirth cohort. We used multiple linear regression and logistic regression, adjusted for potential confounders including maternal age, race, prepregnancy body mass index, and smoking to relate maternal lead to infant birth size and risk for preterm birth (<37 weeks). RESULTS Mean RBC lead level was 1.2 μg/dL (range, 0.0-5.0). Mean (standard deviation) birthweight was 3505 (520) g, birthweight for gestational age z-score 0.22 (0.93), and length of gestation 39.5 (1.7) weeks. Mothers in the highest versus lowest lead quartile did not have higher odds (OR, 1.85; 95% confidence interval [CI], 0.79-4.34) of preterm delivery; after stratifying by child sex, there was an association among males (OR, 5.51; 95% CI, 1.21-25.15) but not females (OR, 0.82; 95% CI, 0.24-2.85). Maternal RBC lead was not associated with any continuous outcomes in combined or sex-stratified analyses. CONCLUSIONS Maternal lead exposure, even at very low levels, may adversely affect some childbirth outcomes, particularly preterm birth among males.
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Affiliation(s)
- Meghan Perkins
- Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, MA
| | - Robert O Wright
- Departments of Preventive Medicine and Pediatrics, Icahn School of Medicine at Mt. Sinai, New York, NY
| | | | - Innocent Jayawardene
- Channing Laboratory, Brigham and Women׳s Hospital and Harvard Medical School, Boston, MA
| | - Sheryl L Rifas-Shiman
- Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, MA
| | - Emily Oken
- Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, MA.
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Park S, Cho SC, Hong YC, Kim JW, Shin MS, Yoo HJ, Han DH, Cheong JH, Kim BN. Environmental tobacco smoke exposure and children's intelligence at 8-11 years of age. ENVIRONMENTAL HEALTH PERSPECTIVES 2014; 122:1123-8. [PMID: 24911003 PMCID: PMC4181918 DOI: 10.1289/ehp.1307088] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 06/02/2014] [Indexed: 05/25/2023]
Abstract
BACKGROUND Evidence supporting a link between postnatal environmental tobacco smoke (ETS) exposure and cognitive problems among children is mounting, but inconsistent. OBJECTIVES We examined the relationship between ETS exposure, measured using urine cotinine, and IQ scores in Korean school-aged children. METHODS The participants were 996 children 8-11 years of age recruited from five administrative regions in South Korea. We performed a cross-sectional analysis of urinary cotinine concentrations and IQ scores obtained using the abbreviated form of a Korean version of the Wechsler Intelligence Scales for Children. Associations were adjusted for potential confounders, and estimates were derived with and without adjustment for mother's Full-Scale IQ (FSIQ) score. RESULTS After adjusting for sociodemographic and developmental covariates, urinary cotinine concentrations were inversely associated with FSIQ, Verbal IQ (VIQ), Performance IQ (PIQ), vocabulary, math, and block design scores. Following further adjustment for maternal IQ, only the VIQ scores remained significantly associated with urinary cotinine concentration (B = -0.31; 95% CI: -0.60, -0.03 for a 1-unit increase in natural log-transformed urine cotinine concentration; p = 0.03). CONCLUSION Urine cotinine concentrations were inversely associated with children's VIQ scores before and after adjusting for maternal IQ. Further prospective studies with serial measurements of cotinine are needed to confirm our findings.
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Affiliation(s)
- Subin Park
- Department of Psychiatry, Seoul National Hospital, Seoul, Republic of Korea
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Abstract
This paper briefly reviews the social science on “neighborhood effects” as an independent force in shaping poor outcomes, specifically mental illness and criminal behavior, before discussing the implications of that research for understanding the relationship between neighborhoods, race and class. Neighborhood effects research has proliferated in recent years with extensive attention again being focused on the social context of family and individual development and life course. Moreover, recent work has suggested the need to consider the developmental effects of neighborhoods that persist across life-span. This paper will focus specifically on mental illness and criminal behavior as outcomes for understanding neighborhood effects, but will also consider what the structural causes of individual behavior and functioning mean for clinical assessment, especially forensic assessment.
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Affiliation(s)
- David Freedman
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - George W Woods
- Morehouse University School of Medicine, Atlanta, GA, USA
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Horton MK, Kahn LG, Perera F, Barr DB, Rauh V. Does the home environment and the sex of the child modify the adverse effects of prenatal exposure to chlorpyrifos on child working memory? Neurotoxicol Teratol 2012; 34:534-41. [PMID: 22824009 PMCID: PMC3901426 DOI: 10.1016/j.ntt.2012.07.004] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Revised: 07/10/2012] [Accepted: 07/16/2012] [Indexed: 11/20/2022]
Abstract
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.
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Affiliation(s)
- Megan K Horton
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY 10032, United States.
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Wong CM, Yang L, Chan KP, Chan WM, Song L, Lai HK, Thach TQ, Ho LM, Chan KH, Lam TH, Peiris JSM. Cigarette smoking as a risk factor for influenza-associated mortality: evidence from an elderly cohort. Influenza Other Respir Viruses 2012; 7:531-9. [PMID: 22813463 PMCID: PMC5855151 DOI: 10.1111/j.1750-2659.2012.00411.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Please cite this paper as: Wong et al. (2012) Cigarette smoking as a risk factor for influenza‐associated mortality: evidence from an elderly cohort. Influenza and Other Respiratory Viruses 7(4), 531–539. Background The effects of individual lifestyle factors on the mortality risk after influenza infection have not been explored. Objectives In this study, we assessed the modifying effects of cigarette smoking on mortality risks associated with influenza in a cohort of Hong Kong elders with a follow‐up period of 1998–2009. Methods We used the Cox proportional hazards model with time‐dependent covariates of weekly proportions of specimens positive for influenza (termed as influenza virus activity), to calculate the hazard ratio of mortality associated with a 10% increase in influenza virus activity for never, ex‐ and current smokers. Other individual lifestyle and socioeconomic factors as well as seasonal confounders were also added into the models. Results The overall hazard ratio associated with influenza was 1·028 (95% confidence interval, 1·006, 1·051) for all natural cause mortality and 1·035 (1·003, 1·068) for cardiovascular and respiratory mortality. We found that influenza‐associated hazard ratio was greater in current and ex‐smokers than in never smokers for mortality of all natural causes, cardiovascular and respiratory diseases. Conclusions The findings suggest that smoking might increase influenza‐associated mortality risks among elders.
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Affiliation(s)
- Chit M Wong
- School of Public Health, The University of Hong Kong, Hong Kong, China
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Kasten-Jolly J, Pabello N, Bolivar VJ, Lawrence DA. Developmental lead effects on behavior and brain gene expression in male and female BALB/cAnNTac mice. Neurotoxicology 2012; 33:1005-20. [PMID: 22609695 DOI: 10.1016/j.neuro.2012.04.017] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Revised: 02/02/2012] [Accepted: 04/17/2012] [Indexed: 12/21/2022]
Abstract
Lead (Pb) was one of the first poisons identified, and the developing nervous system is particularly vulnerable to its toxic effects. Relatively low, subclinical doses, of Pb that produce no overt signs of encephalopathy can affect cognitive, emotional, and motor functions. In the present study, the effects of developmental Pb-exposure on behavioral performance and gene expression in BALB/cAnNTac mice were evaluated. Pups were exposed to Pb from gestational-day (gd) 8 to postnatal-day (pnd) 21 and later evaluated in exploratory behavior, rotarod, Morris water maze, and resident-intruder assays as adults. Pb-exposure caused significant alterations in exploratory behavior and water maze performance during the probe trial, but rotarod performance was not affected. Pb-exposed males displayed violent behavior towards their cage mates, but not to a stranger in the resident-intruder assay. Gene expression analysis at pnd21 by microarray and qRT-PCR was performed to provide a molecular link to the behavior changes that were observed. Pb strongly up-regulated gene expression within the signaling pathways of mitogen activated protein kinases (MAPKs), extra-cellular matrix (ECM) receptor, focal adhesion, and vascular endothelial growth-factor (VEGF), but Pb down-regulated gene expression within the pathways for glycan structures-biosynthesis 1, purine metabolism, and N-glycan biosynthesis. Pb increased transcription of genes for major histocompatibility (MHC) proteins, the chemokine Ccl28, chemokine receptors, IL-7, IL7R, and proteases. The qRT-PCR analysis indicated an increase of gene expression in the whole brain for caspase 1 and NOS2. Analysis of IL-1β, caspase 1, NOS2, Trail, IL-18 and IL-33 gene expression of brain regions indicated that Pb perturbed the inter-regional expression pattern of pro-inflammatory genes. Brain region protein concentrations for IL-10, an anti-inflammatory cytokine, showed a significant decrease only within the cortex region. Results indicate that Pb differentially affects the behavior of male and female mice in that females did less exploration and the males were selectively more aggressive. Gene expression data pointed to evidence of neuroinflammation in the brain of both female and male mice. Pb had more of an effect in the males on expression of vomeronasal receptor genes associated with odor detection and social behavior.
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Affiliation(s)
- Jane Kasten-Jolly
- New York State Department of Health, Wadsworth Center, Albany, NY 12208, USA.
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Stewart PW, Reihman J, Lonky E, Pagano J. Issues in the interpretation of associations of PCBs and IQ. Neurotoxicol Teratol 2012; 34:96-107. [DOI: 10.1016/j.ntt.2011.11.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 11/18/2011] [Accepted: 11/18/2011] [Indexed: 10/14/2022]
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Schwartz J, Bellinger D, Glass T. Exploring potential sources of differential vulnerability and susceptibility in risk from environmental hazards to expand the scope of risk assessment. Am J Public Health 2011; 101 Suppl 1:S94-101. [PMID: 22021315 DOI: 10.2105/ajph.2011.300272] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Genetic factors, other exposures, individual disease states and allostatic load, psychosocial stress, and socioeconomic position all have the potential to modify the response to environmental exposures. Moreover, many of these modifiers covary with the exposure, leading to much higher risks in some subgroups. These are not theoretical concerns; rather, all these patterns have already been demonstrated in studies of the effects of lead and air pollution. However, recent regulatory impact assessments for these exposures have generally not incorporated these findings. Therefore, differential risk and vulnerability is a critically important but neglected area within risk assessment, and should be incorporated in the future.
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Affiliation(s)
- Joel Schwartz
- Department of Environmental Health and Epidemiology, Harvard School of Public Health, and Harvard Center for Risk Analysis, Harvard University, Boston, MA 02215, USA.
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Schwartz J, Bellinger D, Glass T. Expanding the scope of risk assessment: methods of studying differential vulnerability and susceptibility. Am J Public Health 2011; 101 Suppl 1:S102-9. [PMID: 22021313 DOI: 10.2105/ajph.2011.300367] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Several methodological issues have been identified in analysis of epidemiological data to better assess the distributional effects of exposures and hypotheses about effect modification. We discuss the hierarchical mixed model and some more complex methods. Methods of capturing inequality are a second dimension of risk assessment, and simulation studies are important because plausible choices for air pollution effects and effect modifiers could result in extremely high risks in a small subset of the population. Future epidemiological studies should explore contextual and individual-level factors that might modify these relationships. The Environmental Protection Agency should make this a standard part of their risk assessments whenever the necessary information is available.
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Affiliation(s)
- Joel Schwartz
- School of Public Health, Harvard University, Boston, MA, USA.
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Lewis AS, Sax SN, Wason SC, Campleman SL. Non-chemical stressors and cumulative risk assessment: an overview of current initiatives and potential air pollutant interactions. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2011; 8:2020-73. [PMID: 21776216 PMCID: PMC3138011 DOI: 10.3390/ijerph8062020] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/24/2011] [Accepted: 05/20/2011] [Indexed: 12/30/2022]
Abstract
Regulatory agencies are under increased pressure to consider broader public health concerns that extend to multiple pollutant exposures, multiple exposure pathways, and vulnerable populations. Specifically, cumulative risk assessment initiatives have stressed the importance of considering both chemical and non-chemical stressors, such as socioeconomic status (SES) and related psychosocial stress, in evaluating health risks. The integration of non-chemical stressors into a cumulative risk assessment framework has been largely driven by evidence of health disparities across different segments of society that may also bear a disproportionate risk from chemical exposures. This review will discuss current efforts to advance the field of cumulative risk assessment, highlighting some of the major challenges, discussed within the construct of the traditional risk assessment paradigm. Additionally, we present a summary of studies of potential interactions between social stressors and air pollutants on health as an example of current research that supports the incorporation of non-chemical stressors into risk assessment. The results from these studies, while suggestive of possible interactions, are mixed and hindered by inconsistent application of social stress indicators. Overall, while there have been significant advances, further developments across all of the risk assessment stages (i.e., hazard identification, exposure assessment, dose-response, and risk characterization) are necessary to provide a scientific basis for regulatory actions and effective community interventions, particularly when considering non-chemical stressors. A better understanding of the biological underpinnings of social stress on disease and implications for chemical-based dose-response relationships is needed. Furthermore, when considering non-chemical stressors, an appropriate metric, or series of metrics, for risk characterization is also needed. Cumulative risk assessment research will benefit from coordination of information from several different scientific disciplines, including, for example, toxicology, epidemiology, nutrition, neurotoxicology, and the social sciences.
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Affiliation(s)
- Ari S. Lewis
- Gradient, 20 University Road, Cambridge, MA 02138, USA; E-Mail:
| | - Sonja N. Sax
- Gradient, 20 University Road, Cambridge, MA 02138, USA; E-Mail:
| | - Susan C. Wason
- Department of Environmental Health, Harvard School of Public Health, 401 Park Drive, Boston, MA 02215, USA; E-Mail:
| | - Sharan L. Campleman
- Electric Power Research Institute, 3420 Hillview Ave., Palo Alto, CA 94304, USA; E-Mail:
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Lee BK, Glass TA, James BD, Bandeen-Roche K, Schwartz BS. Neighborhood psychosocial environment, apolipoprotein E genotype, and cognitive function in older adults. ACTA ACUST UNITED AC 2011; 68:314-21. [PMID: 21383266 DOI: 10.1001/archgenpsychiatry.2011.6] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
CONTEXT The social environment may influence cognitive function in aging. However, to our knowledge, no studies have investigated whether specific genes modify this association. OBJECTIVE To examine whether the apolipoprotein E (APOE) ε4 allele modifies the association of neighborhood psychosocial hazards and cognitive function. DESIGN A cross-sectional analysis. SETTING The Baltimore Memory Study, a population-based sample of older urban residents. The 65 study neighborhoods in Baltimore, Maryland, were characterized using the Neighborhood Psychosocial Hazards Scale, designed to assess social disorganization, physical disorder, public safety, and economic deprivation. PARTICIPANTS One thousand one hundred forty urban residents aged 50 to 70 years at baseline. MAIN OUTCOME MEASURES Cognitive performance on 20 standard tests was measured and combined to form 7 summary domain scores (language, processing speed, eye-hand coordination, executive functioning, verbal memory and learning, visual memory, and visuoconstruction). RESULTS In analyses fully adjusted for individual covariates, we found that high (ie, worse) neighborhood psychosocial hazards were not consistently associated with worse cognitive performance. However, the interaction of high neighborhood psychosocial hazards and APOE ε4 genotype was found to be associated with worse cognitive domain scores, with evidence of associations in the domains of processing speed (P = .02) and executive functioning (P < .001). Suggestive evidence was also found for eye-hand coordination (P = .05). CONCLUSION Living in a psychosocially hazardous neighborhood was associated with worse cognitive function in persons with the APOE ε4 allele, evidence of a novel gene × environment interaction.
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Affiliation(s)
- Brian K Lee
- Department of Epidemiology and Biostatistics, Drexel University School of Public Health, Philadelphia, Pennsylvania, USA.
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Abstract
RÉSUMÉPubMed fournit plus de 6,000 références (700 critiques) sur les chutes accidentelles des personnes âgées. Cet article retrace les jalons principaux et méthodologiques dans l’application de méthodes épidémiologiques depuis les premières publications dans ce domaine, à la fin des années quarante. Dans le contexte des avances faites en définition des cas médicaux, échantillonnage, mesure, conception de la recherche et l’analyse statistique, l’article passe en revue les estimations de fréquence d’apparition, les associations de facteurs de risque, les conséquences de la morbidité et de la mortalité, la démonstration de la théorie des facteurs multirisques à l’aide des interventions sur la prévention des chutes et les défis de modèles de prédiction des risques de chutes. Les explications méthodologiques sont fournies pour les hétérogénéités observées et le cas médical est présenté en faveur d’aller au-delà des listes indifférenciées des facteurs de risque, en mettant l’accent sur l’équilibre et la démarche comme les facteurs par lesquels on peut mieux comprendre les effets mécanistes des facteurs de risque distaux. En outre, l’affaire est faite pour faire avancer nos analyses statistiques en examinant les interactions parmi les facteurs de risque intrinsèques et entre les facteurs intrinsèques, extrinsèques et environnementaux.
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Lynch ML, Huang LS, Cox C, Strain JJ, Myers GJ, Bonham MP, Shamlaye CF, Stokes-Riner A, Wallace JMW, Duffy EM, Clarkson TW, Davidson PW. Varying coefficient function models to explore interactions between maternal nutritional status and prenatal methylmercury toxicity in the Seychelles Child Development Nutrition Study. ENVIRONMENTAL RESEARCH 2011; 111:75-80. [PMID: 20961536 PMCID: PMC3032628 DOI: 10.1016/j.envres.2010.09.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2009] [Revised: 09/10/2010] [Accepted: 09/16/2010] [Indexed: 05/17/2023]
Abstract
Maternal consumption of fish during the gestational period exposes the fetus to both nutrients, especially the long-chain polyunsaturated fatty acids (LCPUFAs), believed to be beneficial for fetal brain development, as well as to the neurotoxicant methylmercury (MeHg). We recently reported that nutrients present in fish may modify MeHg neurotoxicity. Understanding the apparent interaction of MeHg exposure and nutrients present in fish is complicated by the limitations of modeling methods. In this study we fit varying coefficient function models to data from the Seychelles Child Development Nutrition Study (SCDNS) cohort to assess the association of dietary nutrients and children's development. This cohort of mother-child pairs in the Republic of Seychelles had fish consumption averaging 9 meals per week. Maternal nutritional status was assessed for five different nutritional components known to be present in fish (n-3 LCPUFA, n-6 LCPUFA, iron status, iodine status, and choline) and associated with children's neurological development. We also included prenatal MeHg exposure (measured in maternal hair). We examined two child neurodevelopmental outcomes (Bayley Scales Infant Development-II (BSID-II) Mental Developmental Index (MDI) and Psychomotor Developmental Index (PDI)), each administered at 9 and at 30 months. The varying coefficient models allow the possible interactions between each nutritional component and MeHg to be modeled as a smoothly varying function of MeHg as an effect modifier. Iron, iodine, choline, and n-6 LCPUFA had little or no observable modulation at different MeHg exposures. In contrast the n-3 LCPUFA docosahexaenoic acid (DHA) had beneficial effects on the BSID-II PDI that were reduced or absent at higher MeHg exposures. This study presents a useful modeling method that can be brought to bear on questions involving interactions between covariates, and illustrates the continuing importance of viewing fish consumption during pregnancy as a case of multiple exposures to nutrients and to MeHg. The results encourage more emphasis on a holistic view of the risks and benefits of fish consumption as it relates to infant development.
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Affiliation(s)
- Miranda L Lynch
- Department of Biostatistics and Computational Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA.
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Cho SC, Bhang SY, Hong YC, Shin MS, Kim BN, Kim JW, Yoo HJ, Cho IH, Kim HW. Relationship between environmental phthalate exposure and the intelligence of school-age children. ENVIRONMENTAL HEALTH PERSPECTIVES 2010; 118:1027-32. [PMID: 20194078 PMCID: PMC2920903 DOI: 10.1289/ehp.0901376] [Citation(s) in RCA: 180] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Accepted: 03/01/2010] [Indexed: 05/18/2023]
Abstract
BACKGROUND Concern over phthalates has emerged because of their potential toxicity to humans. OBJECTIVE We investigated the relationship between the urinary concentrations of phthalate metabolites and children's intellectual functioning. METHODS This study enrolled 667 children at nine elementary schools in five South Korean cities. A cross-sectional examination of urine phthalate concentrations was performed, and scores on neuropsychological tests were obtained from both the children and their mothers. RESULTS We measured mono-2-ethylhexyl phthalate (MEHP) and mono(2-ethyl-5-oxohexyl)phthalate (MEOHP), both metabolites of di(2-ethylhexyl)phthalate (DEHP), and mono-n-butyl phthalate (MBP), a metabolite of dibutyl phthalate (DBP), in urine samples. The geometric mean (ln) concentrations of MEHP, MEOHP, and MBP were 21.3 microg/L [geometric SD (GSD) = 2.2 microg/L; range, 0.5-445.4], 18.0 microg/L (GSD = 2.4; range, 0.07-291.1), and 48.9 microg/L (GSD = 2.2; range, 2.1-1645.5), respectively. After adjusting for demographic and developmental covariates, the Full Scale IQ and Verbal IQ scores were negatively associated with DEHP metabolites but not with DBP metabolites. We also found a significant negative relationship between the urine concentrations of the metabolites of DEHP and DBP and children's vocabulary subscores. After controlling for maternal IQ, a significant inverse relationship between DEHP metabolites and vocabulary subscale score remained. Among boys, we found a negative association between increasing MEHP phthalate concentrations and the sum of DEHP metabolite concentrations and Wechsler Intelligence Scale for Children vocabulary score; however, among girls, we found no significant association between these variables. CONCLUSION Controlling for maternal IQ and other covariates, the results show an inverse relationship between phthalate metabolites and IQ scores; however, given the limitations in cross-sectional epidemiology, prospective studies are needed to fully explore these associations.
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Affiliation(s)
- Soo-Churl Cho
- Division of Child and Adolescent Psychiatry, Department of Psychiatry and Institute of Human Behavioral Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Soo-Young Bhang
- Department of Psychiatry, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Republic of Korea
- Address correspondence to S. Bhang, Department of Psychiatry, Ulsan University Hospital, University of Ulsan College of Medicine, 290-3 Jeonha-Dong, Dong-Gu, Ulsan, 682-714, South Korea. Telephone: 82-52-250- 7070. Fax: 82-52-232-3309. E-mail:
| | - Yun-Chul Hong
- Department of Preventive Medicine, Seoul National University College of Medicine and Institute of Environmental Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea
| | - Min-Sup Shin
- Division of Child and Adolescent Psychiatry, Department of Psychiatry and Institute of Human Behavioral Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Boong-Nyun Kim
- Division of Child and Adolescent Psychiatry, Department of Psychiatry and Institute of Human Behavioral Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Jae-Won Kim
- Division of Child and Adolescent Psychiatry, Department of Psychiatry and Institute of Human Behavioral Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Hee-Jung Yoo
- Department of Psychiatry, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - In Hee Cho
- Department of Psychiatry, Gil Medical Center, Gachon University of Medicine and Science, Incheon, Republic of Korea
| | - Hyo-Won Kim
- Department of Neuropsychiatry, Dongguk University International Hospital, Dongguk University College of Medicine, Goyang, Republic of Korea
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Willoughby M, Greenberg M, Blair C, Stifter C. Neurobehavioral Consequences of Prenatal Exposure to Smoking at 6 to 8 Months of Age. INFANCY 2010. [DOI: 10.1111/j.1532-7078.2007.tb00244.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Michael Willoughby
- FPG Child Development Institute, University of North Carolina at Chapel Hill
| | - Mark Greenberg
- Prevention Research Center, Pennsylvania State University
| | - Clancy Blair
- Human Development and Family Studies, Pennsylvania State University
| | - Cynthia Stifter
- Human Development and Family Studies, Pennsylvania State University
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Oliveira da Costa Mattos RDC, Xavier EC, Domingos Mainenti HR, Mitri Nogueira S, Ribeiro de Carvalho MA, Ramos Moreira MDF, Vargas de Carvalho LB, Tabalipa M, Borges R, Malizia Alves MDF. Evaluation of calcium excretion in Brazilian infantile and young population environmentally exposed to lead. Hum Exp Toxicol 2009; 28:567-75. [PMID: 19737813 DOI: 10.1177/0960327109102804] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Lead exposure is an important issue in the research of several toxic effects resulting from the biochemical interaction between this metal and the organism. Calcium is a fundamental mineral for the maintenance of the organism homeostasis where there is interaction between lead and calcium in metabolic pathways. Environmental lead exposure by verifying the usefulness and applicability of urinary calcium/creatinine ratio (UCa/Cr) in this context was evaluated. This was an extensive socio-demographic study of the nutritional profile, lead exposure biomarkers in blood and the urine and UCa/Cr ratio. The children studied were from a low socio-economic group characterized by unsatisfactory nutritional diet. Lead environmental exposure was shown by biomarkers, with UCa/Cr ratio having positive and significant correlations with both lead and delta-aminolevulinic acid in urine (ALA-U), without colinearity diagnosis. There was a strong association between calcium excretion and lead exposure as a result of linear regression construction models. In children, lead increases calcium excretion which is an additional risk to infantile health. Urinary calcium/creatinine ratio may be a useful tool in the biological monitoring of lead exposure and health promotion programs.
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Affiliation(s)
- Rita de Cássia Oliveira da Costa Mattos
- Laboratory of Toxicology, Workers' Health and Human Ecology Studies Center, Sergio Arouca National Public Health School, Oswaldo Cruz Foundation, Rio de Janeiro, RJ, Brazil.
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Bellinger DC. Interpreting epidemiologic studies of developmental neurotoxicity: conceptual and analytic issues. Neurotoxicol Teratol 2009; 31:267-74. [PMID: 19595760 DOI: 10.1016/j.ntt.2009.06.006] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2009] [Revised: 06/20/2009] [Accepted: 06/25/2009] [Indexed: 11/25/2022]
Abstract
This paper discusses issues pertaining to the validity, precision, and interpretation of epidemiologic studies of neurotoxicity. With regard to validity, the critical issues pertain to the appropriate strategy for confounder adjustment, particularly when confounders are complex, multi-faceted constructs, and to the need for greater clarity and transparency in articulating the causal relationships implicit in the analytic approach applied. With regard to precision, the critical issue is a need to identify the contributors to the substantial variability observed in the effect estimates that describe dose-response and dose-effect relationships. In addition to methodological sources, such as imprecision in estimating dose at the critical organ site(s), true inter-individual differences in susceptibility to a neurotoxicant could also contribute to the variability. Variability might be reduced by taking full account of factors such as co-exposures or health co-morbidities, genetic polymorphisms, and the social ecology of exposure. With regard to interpretation, we need to do a better job as a field conveying to risk assessors and others the ecological significance of the types of performance deficits observed following neurotoxicant exposure, emphasizing the distinction between individual and population risk. A final issue discussed is the need to define standards for the conduct, analysis, and reporting of epidemiologic studies of neurotoxicity, similar to those developed for other fields.
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Affiliation(s)
- David C Bellinger
- Children's Hospital Boston, Harvard Medical School, Harvard School of Public Health, Farley Basement Box 127, Children's Hospital, Boston, MA 02115, USA.
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Jones HE, Kaltenbach K, O'Grady KE. The complexity of examining developmental outcomes of children prenatally exposed to opiates. A response to the Hunt et al. Adverse neurodevelopmental outcome of infants exposed to opiates in-utero. Early Human Development (2008, 84, 29-35). Early Hum Dev 2009; 85:271-2. [PMID: 19008056 DOI: 10.1016/j.earlhumdev.2008.10.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2008] [Accepted: 10/07/2008] [Indexed: 11/26/2022]
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Glass TA, Bandeen-Roche K, McAtee M, Bolla K, Todd AC, Schwartz BS. Neighborhood psychosocial hazards and the association of cumulative lead dose with cognitive function in older adults. Am J Epidemiol 2009; 169:683-92. [PMID: 19155330 DOI: 10.1093/aje/kwn390] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Before the 1970s, today's older Americans were exposed to high levels of lead in the environment. The authors previously reported that lifetime cumulative lead dose was associated with lower cognitive test performance in older adults. Experiments suggest that environmental stress may intensify the detrimental influence of lead. No large, population-based studies of this question have been done. The authors evaluated whether cross-sectional associations of tibia lead with cognitive function were modified by neighborhood psychosocial hazards in the Baltimore Memory Study (2001-2005), a longitudinal cohort study of determinants of cognitive decline. Tibia lead was measured via (109)Cd-induced K-shell X-ray fluorescence. Neighborhood psychosocial hazards were measured independently of study subjects. Complete data were available among 1,001 demographically diverse adults aged 50-70 years, randomly selected from 65 contiguous neighborhoods in Baltimore City. Hierarchical mixed-effects regression models showed that neighborhood psychosocial hazards exacerbated the adverse associations of tibia lead in 3 of 7 cognitive domains after adjustment for age, sex, race/ethnicity, education, testing technician, and time of day (language, P = 0.039; processing speed, P = 0.067; executive functioning, P = 0.025). The joint occurrence of environmental stress and lead exposure across the life span may partially explain persistent racial/ethnic and socioeconomic disparities in cognitive function in late life.
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Affiliation(s)
- Thomas A Glass
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA.
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Janjua NZ, Delzell E, Larson RR, Meleth S, Kabagambe EK, Kristensen S, Sathiakumar N. Maternal nutritional status during pregnancy and surma use determine cord lead levels in Karachi, Pakistan. ENVIRONMENTAL RESEARCH 2008; 108:69-79. [PMID: 18656859 PMCID: PMC2581773 DOI: 10.1016/j.envres.2008.06.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2007] [Revised: 06/05/2008] [Accepted: 06/12/2008] [Indexed: 05/05/2023]
Abstract
OBJECTIVES To estimate the umbilical cord blood lead levels (BLLs) of Pakistani neonates and to identify determinants for umbilical BLLs. METHODS We conducted a cross-sectional study of mothers and infants at one of the two obstetric units of two tertiary care hospitals in Karachi during January-August 2005. Information from 540 mothers selected randomly from those registered for delivery was obtained about their pregnancy, diet, and current and past lead exposures. We collected umbilical cord blood for lead levels analyzed using graphite furnace atomic absorption spectrophotometry. We computed geometric and arithmetic means. We performed multiple linear regression analysis to identify factors associated with log-transformed umbilical cord BLLs. We also performed logistic regression analysis to identify determinants of high lead cord BLLs (10 microg/dl). RESULTS The geometric mean cord BLL of the neonates was 9.6 microg/dl; arithmetic mean (S.D.) was 10.8 microg/dl (5.7) with a median of 9.7 microg/dl and a range of 1.8-48.9 microg/dl. Women who reported intake of less than 58.5mg of elemental iron supplement per day during pregnancy had cord BLL of 10.0 microg/dl; in comparison those women who had higher iron intake had lower cord BLL (8.4 microg/dl). Those who used surma (an eye cosmetic) daily had higher cord BLL (11.5 microg/dl) as compared to those who used it less frequently (9.4 microg/dl). In multivariable linear regression model, higher iron intake, owning a car, and being in 2nd quartile of mid-arm circumference were associated with low lead levels while father's occupation in lead-based industry was associated with significantly higher umbilical cord BLLs. There was interaction of daily surma use and ethnicity. Geometric mean BLLs were varied among surma users by ethnicity. CONCLUSIONS Umbilical cord BLLs are high in Karachi, Pakistan, in comparison to those in developed countries such as United States. Measures are needed to reduce fetal lead exposure to prevent adverse affect on neurocognitive development. Association of low iron (below RDA of 60 mg per day) with high umbilical cord has implications for strengthening iron supplement intake during pregnancy. Umbilical cord BLLs differed among surma users by ethnicity.
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Affiliation(s)
- Naveed Zafar Janjua
- Department of Epidemiology, University of Alabama at Birmingham, 1665 University Blvd, RPHB 430, Birmingham, AL 35294, USA.
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Rice DC. Overview of modifiers of methylmercury neurotoxicity: chemicals, nutrients, and the social environment. Neurotoxicology 2008; 29:761-6. [PMID: 18722469 DOI: 10.1016/j.neuro.2008.07.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2008] [Revised: 06/26/2008] [Accepted: 07/07/2008] [Indexed: 10/21/2022]
Abstract
It has been known for decades that methylmercury is a potent neurotoxicant, and that the developing brain is more susceptible to impairment as a result of methylmercury exposure than is the adult. Exposure to methylmercury is exclusively through consumption of fish and marine mammals. In recent years, the potential for protection against methylmercury toxicity by nutrients present in fish, particularly omega-3 fatty acids and selenium, has been explored in both epidemiological and experimental studies. There is evidence from several studies that fish consumption per se and methylmercury body burden act in opposition with regard to neuropsychological outcomes, whereas the evidence for a protective effect of specific nutrients is contradictory in both epidemiological and experimental studies published to date. The potential for methylmercury to interact with other chemicals present in marine food, particularly PCBs, has been explored in both animal models and human studies. Results may be both exposure- and endpoint-dependent. The Seychelles Islands study has explored the potential for the social environment to modify the effects of developmental methylmercury exposure. An understanding of the interactions of the multiple factors that determine the final behavioral outcome of exposure to methylmercury is crucial to risk assessment and risk management decisions.
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Affiliation(s)
- Deborah C Rice
- Maine Center for Disease Control and Prevention, Augusta, ME 04333, United States.
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Theppeang K, Glass TA, Bandeen-Roche K, Todd AC, Rohde CA, Links JM, Schwartz BS. Associations of bone mineral density and lead levels in blood, tibia, and patella in urban-dwelling women. ENVIRONMENTAL HEALTH PERSPECTIVES 2008; 116:784-790. [PMID: 18560535 PMCID: PMC2430235 DOI: 10.1289/ehp.10977] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2007] [Accepted: 02/26/2008] [Indexed: 05/26/2023]
Abstract
OBJECTIVE The objective of this study was to evaluate the relations between bone mineral density (BMD) and lead in blood, tibia, and patella and to investigate how BMD modifies these lead biomarkers in older women. DESIGN In this study, we used cross-sectional analysis. PARTICIPANTS We studied 112 women, 50-70 years of age, including both whites and African Americans, residing in Baltimore, Maryland. MEASUREMENTS We measured lumbar spine BMD, blood and bone lead by dual energy X-ray absorptiometry, anodic stripping voltammetry, and (109)Cd-induced K-shell X-ray fluorescence, respectively. We measured vitamin D receptor and apolipoprotein E (APOE) genotypes using standard methods. RESULTS Mean (+/- SD) BMD and lead levels in blood, tibia, and patella were 1.02+/-0.16 g/cm(2), 3.3+/-2.2 microg/dL, 19.7+/-13.2 microg/g, and 5.7+/-15.3 microg/g, respectively. In adjusted analysis, higher BMD was associated with higher tibia lead levels (p=0.03). BMD was not associated with lead levels in blood or patella. There was evidence of significant effect modification by BMD on relations of physical activity with blood lead levels and by APOE genotype on relations of BMD with tibia lead levels. There was no evidence that BMD modified relations between tibia lead or patella lead and blood lead levels. CONCLUSIONS We believe that BMD represents the capacity of bone that can store lead, by substitution for calcium, and thus the findings may have relevance for effect-size estimates in persons with higher BMD. RELEVANCE TO CLINICAL PRACTICE The results have implications for changes in lead kinetics with aging, and thus the related risk of health effects associated with substantial early- and midlife lead exposure in older persons.
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Affiliation(s)
- Keson Theppeang
- Department of Environmental Health Sciences
- Department of Biostatistics, and
| | - Thomas A. Glass
- Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA
| | | | - Andrew C. Todd
- Department of Community and Preventive Medicine, Mount Sinai School of Medicine, New York, New York
| | | | | | - Brian S. Schwartz
- Department of Environmental Health Sciences
- Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA
- Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
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Abstract
PURPOSE OF REVIEW We remain far from achieving the goal of eliminating lead-associated neurodevelopmental morbidities in children. New evidence regarding the blood lead levels at which morbidities occur have led to calls for the Centers for Disease Control and Prevention to reduce the current screening guideline of 10 microg/dl. The review evaluates the basis for these calls. RECENT FINDINGS Adverse outcomes, such as reduced intelligence quotient and academic deficits, occur at levels below 10 microg/dl. Some studies suggest that the rate of decline in performance is greater at levels below 10 microg/dl than above 10 microg/dl, although a plausible mechanism has not been identified. Increased exposure is also associated with neuropsychiatric disorders such as attention deficit hyperactivity disorder and antisocial behavior. Functional imaging studies are beginning to provide insight into the neural substrate of lead's neurodevelopmental effects. Current protocols for chelation therapy appear ineffective in preventing such effects, although environmental enrichment might do so. SUMMARY No level of lead exposure appears to be 'safe' and even the current 'low' levels of exposure in children are associated with neurodevelopmental deficits. Primary prevention of exposure provides the best hope of mitigating the impact of this preventable disease.
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