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Kampouri M, Zander E, Gustin K, Sandin A, Barman M, Sandberg AS, Wold AE, Bölte S, Kippler M, Vahter M. Associations of gestational and childhood exposure to lead, cadmium, and fluoride with cognitive abilities, behavior, and social communication at 4 years of age: NICE birth cohort study. ENVIRONMENTAL RESEARCH 2024; 263:120123. [PMID: 39389199 DOI: 10.1016/j.envres.2024.120123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2024] [Revised: 10/03/2024] [Accepted: 10/06/2024] [Indexed: 10/12/2024]
Abstract
BACKGROUND Early-life lead exposure affects cognitive development and emerging evidence suggests similar effects of cadmium and fluoride. OBJECTIVE To assess the impact of gestational and childhood exposure to lead, cadmium, and fluoride on cognitive abilities and behavioral and social communication problems. METHODS We studied 470 pregnant women (gestational week 29) and their 4-year-old children from the NICE cohort in northern Sweden. Concentrations of erythrocyte lead and cadmium and urinary cadmium were measured using inductively coupled plasma mass spectrometry and urinary fluoride with an ion-selective electrode. Urinary concentrations were specific-gravity adjusted. Associations of log2-transformed exposure concentrations with cognitive abilities (full-scale IQ and verbal comprehension by Wechsler Preschool and Primary Scale of Intelligence-Fourth Edition), behavioral problems (Child Behavior Checklist), and social communication (Social Responsiveness Scale-Second Edition) were evaluated with multivariable-adjusted linear regression analysis. RESULTS Both gestational and cord erythrocyte lead concentrations were non-significantly inversely associated with child cognitive abilities (full-scale IQ: B [95%CI]: -1.2 [-2.9, 0.5] and -1.6 [-3.7, 0.4], respectively; per doubling of exposure). Similarly, both gestational and child urinary cadmium were inversely associated with cognitive abilities (full-scale IQ: -1.1 [-2.5, 0.3] and -1.1 [-2.5, 0.4], verbal comprehension: -1.2 [-3.1, 0.6] and -1.4 [-3.4, 0.6], respectively). Urinary fluoride concentrations showed no association with cognitive abilities. However, gestational fluoride was associated with increasing externalizing problems (0.9 [-0.3, 2.0]) and ADHD raw scores (0.3 [0.0, 0.6]). Childhood erythrocyte lead and urinary cadmium were non-significantly associated with increased behavioral problems (lead with total problems: 1.2 [-0.4, 2.9] and internalizing problems: 1.5 [-0.4, 3.4]; cadmium with externalizing problems: 1.1 [-0.2, 2.4]). CONCLUSION Despite non-significant associations, both lead and cadmium exposure showed consistent inverse associations with cognitive abilities at 4 years, whereas associations with behavioral problems were less conclusive, especially for cadmium. Results on fluoride indicated association with externalizing problems, including ADHD, but prevalence of behavioral problems was low, increasing uncertainty.
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Affiliation(s)
- Mariza Kampouri
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Eric Zander
- Center of Neurodevelopmental Disorders (KIND), Department of Women's and Children's Health, Centre for Psychiatry Research, Karolinska Institutet & Region Stockholm, Stockholm, Sweden
| | - Klara Gustin
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Anna Sandin
- Department of Clinical Science, Pediatrics, Sunderby Research Unit, Umeå University, Sweden
| | - Malin Barman
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden; Food and Nutrition Science, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
| | - Ann-Sofie Sandberg
- Food and Nutrition Science, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
| | - Agnes E Wold
- Institute of Biomedicine, Department of Infectious Diseases, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Sven Bölte
- Center of Neurodevelopmental Disorders (KIND), Department of Women's and Children's Health, Centre for Psychiatry Research, Karolinska Institutet & Region Stockholm, Stockholm, Sweden; Child and Adolescent Psychiatry, Stockholm Health Care Services, Region Stockholm, Stockholm, Sweden; Curtin Autism Research Group, Curtin School of Allied Health, Curtin University, Perth, Australia
| | - Maria Kippler
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
| | - Marie Vahter
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
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Ramírez V, González-Palacios P, Baca MA, González-Domenech PJ, Fernández-Cabezas M, Álvarez-Cubero MJ, Rodrigo L, Rivas A. Effect of exposure to endocrine disrupting chemicals in obesity and neurodevelopment: The genetic and microbiota link. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 852:158219. [PMID: 36007653 DOI: 10.1016/j.scitotenv.2022.158219] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 08/06/2022] [Accepted: 08/18/2022] [Indexed: 06/15/2023]
Abstract
Current evidence highlights the importance of the genetic component in obesity and neurodevelopmental disorders (attention-deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD) and intellectual disability (ID)), given that these diseases have reported an elevated heritability. Additionally, environmental stressors, such as endocrine disrupting chemicals (EDCs) have been classified as obesogens, neuroendocrine disruptors, and microbiota disrupting chemicals (MDCs). For this reason, the importance of this work lies in examining two possible biological mechanistic pathways linking obesity and neurodevelopmental/behavioural disorders: EDCs - gene and EDCs - microbiota interactions. First, we summarise the shared mechanisms of action of EDCs and the common genetic profile in the bidirectional link between obesity and neurodevelopment. In relation to interaction models, evidence from the reviewed studies reveals significant interactions between pesticides/heavy metals and gene polymorphisms of detoxifying and neurotransmission systems and metal homeostasis on cognitive development, ASD and ADHD symptomatology. Nonetheless, available literature about obesity is quite limited. Importantly, EDCs have been found to induce gut microbiota changes through gut-brain-microbiota axis conferring susceptibility to obesity and neurodevelopmental disorders. In view of the lack of studies assessing the impact of EDCs - gene interactions and EDCs - mediated dysbiosis jointly in obesity and neurodevelopment, we support considering genetics, EDCs exposure, and microbiota as interactive factors rather than individual contributors to the risk for developing obesity and neurodevelopmental disabilities at the same time.
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Affiliation(s)
- Viviana Ramírez
- Department of Nutrition and Food Science, Faculty of Pharmacy, University of Granada, 18071 Granada, Spain; GENYO. Centre for Genomics and Oncological Research: Pfizer / University of Granada / Andalusian Regional Government PTS Granada - Avenida de la Ilustración, 114, 18016 Granada, Spain; "José Mataix Verdú" Institute of Nutrition and Food Technology (INYTA), Biomedical Research Centre (CIBM), University of Granada, 18100 Granada, Spain
| | - Patricia González-Palacios
- Department of Nutrition and Food Science, Faculty of Pharmacy, University of Granada, 18071 Granada, Spain.
| | | | | | - María Fernández-Cabezas
- Department of Developmental and Educational Psychology, Faculty of Educational Sciences, University of Granada, 18011 Granada, Spain
| | - María Jesús Álvarez-Cubero
- GENYO. Centre for Genomics and Oncological Research: Pfizer / University of Granada / Andalusian Regional Government PTS Granada - Avenida de la Ilustración, 114, 18016 Granada, Spain; Department of Biochemistry and Molecular Biology III, Faculty of Medicine, University of Granada, 18016 Granada, Spain; Instituto de Investigación Biosanitaria ibs.GRANADA, 18014 Granada, Spain
| | - Lourdes Rodrigo
- Department of Legal Medicine and Toxicology, Faculty of Medicine, University of Granada, 18016 Granada, Spain
| | - Ana Rivas
- Department of Nutrition and Food Science, Faculty of Pharmacy, University of Granada, 18071 Granada, Spain; "José Mataix Verdú" Institute of Nutrition and Food Technology (INYTA), Biomedical Research Centre (CIBM), University of Granada, 18100 Granada, Spain; Instituto de Investigación Biosanitaria ibs.GRANADA, 18014 Granada, Spain
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Axelrad DA, Coffman E, Kirrane EF, Klemick H. The relationship between childhood blood lead levels below 5 µg/dL and childhood intelligence quotient (IQ): Protocol for a systematic review and meta-analysis. ENVIRONMENT INTERNATIONAL 2022; 169:107475. [PMID: 36162279 PMCID: PMC9896788 DOI: 10.1016/j.envint.2022.107475] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 08/10/2022] [Accepted: 08/12/2022] [Indexed: 05/10/2023]
Abstract
BACKGROUND The causal association between childhood lead (Pb) exposure and decrements in intelligence quotient (IQ) is well-established, and no safe blood lead level (BLL) in children has been identified. An international pooled analysis of seven prospective studies published by Lanphear et al. in 2005 quantified the relationship between childhood BLL and IQ. Further studies of Pb and IQ have been published more recently with mean BLLs generally lower than in the studies analyzed by Lanphear et al. In this article, we present the protocol for a systematic review to estimate an updated Pb-IQ relationship focusing on BLLs below 5 µg per deciliter (µg/dL). STUDY QUESTION What is the quantitative relationship between childhood BLLs and IQ at ages 3-17 years at BLLs below 5 μg/dL? DATA SOURCES A comprehensive search of the scientific literature will utilize citation mapping and key word searching. In the citation mapping approach, we will identify seed references that are relevant to our study question, and will then identify more recent references that have cited at least one of the seed references. The key word search will be conducted in the PubMed, Biosis Previews, Scopus, and Web of Science databases. We will also search electronic grey literature databases for conference proceedings, dissertations, and preprints. STUDY ELIGIBILITY CRITERIA, STUDY SCREENING AND DATA EXTRACTION We will include studies that measured BLL in children at any age, assessed full-scale IQ of the same children (concurrent with or subsequent to BLL sample collection) at ages 3-17, and estimated a continuous quantitative relationship between BLL and IQ. We will consider only studies with a central tendency BLL < 10 µg/dL. The title and abstract of each record will be reviewed independently by two authors to determine whether the study in question satisfies the inclusion criteria. The full text of each article remaining after title-abstract screening will be reviewed independently by two authors to determine whether the study in question satisfies the inclusion criteria. Two authors will independently extract study characteristics and data from each included study. RISK OF BIAS ASSESSMENT Studies meeting inclusion criteria will be evaluated for risk of bias (RoB) using the Navigation Guide method applied in a previous systematic review of neurodevelopmental effects (Lam et al., 2017), with adaptation to our study question. Each study will be independently evaluated by two review authors. DATA ANALYSIS AND SYNTHESIS We intend to conduct a random-effects meta-analysis to summarize the effects of children's exposure to Pb on IQ scores. Additionally, we plan to perform sensitivity analyses using sub-group analyses and/or meta-regression techniques to assess the impact of study design and study population characteristics to examine potential heterogeneity of results across studies. We will assign a confidence level rating (high, moderate, low, or very low) to the effect estimate from the meta-analyses/meta-regressions.
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Affiliation(s)
| | - Evan Coffman
- U.S. Environmental Protection Agency, Office of Research and Development, Center for Public Health and Environmental Assessment, Research Triangle Park, NC, USA.
| | - Ellen F Kirrane
- U.S. Environmental Protection Agency, Office of Research and Development, Center for Public Health and Environmental Assessment, Research Triangle Park, NC, USA.
| | - Heather Klemick
- U.S. Environmental Protection Agency, Office of Policy, National Center for Environmental Economics, Washington, DC, USA.
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Cuomo D, Foster MJ, Threadgill D. Systemic review of genetic and epigenetic factors underlying differential toxicity to environmental lead (Pb) exposure. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:35583-35598. [PMID: 35244845 PMCID: PMC9893814 DOI: 10.1007/s11356-022-19333-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 02/17/2022] [Indexed: 05/03/2023]
Abstract
Lead (Pb) poisoning is a major public health concern in environmental justice communities of the USA and in many developing countries. There is no identified safety threshold for lead in blood, as low-level Pb exposures can lead to severe toxicity in highly susceptible individuals and late onset of diseases from early-life exposure. However, identifying "susceptibility genes" or "early exposure biomarkers" remains challenging in human populations. There is a considerable variation in susceptibility to harmful effects from Pb exposure in the general population, likely due to the complex interplay of genetic and/or epigenetic factors. This systematic review summarizes current state of knowledge on the role of genetic and epigenetic factors in determining individual susceptibility in response to environmental Pb exposure in humans and rodents. Although a number of common genetic and epigenetic factors have been identified, the reviewed studies, which link these factors to various adverse health outcomes following Pb exposure, have provided somewhat inconsistent evidence of main health effects. Acknowledging the compelling need for new approaches could guide us to better characterize individual responses, predict potential adverse outcomes, and identify accurate and usable biomarkers for Pb exposure to improve mitigation therapies to reduce future adverse health outcomes of Pb exposure.
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Affiliation(s)
- Danila Cuomo
- Department of Molecular and Cellular Medicine, Texas A&M University, College Station, TX, USA.
| | - Margaret J Foster
- Medical Sciences Library, Texas A&M University, College Station, TX, USA
| | - David Threadgill
- Department of Molecular and Cellular Medicine and Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA.
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Heng YY, Asad I, Coleman B, Menard L, Benki-Nugent S, Hussein Were F, Karr CJ, McHenry MS. Heavy metals and neurodevelopment of children in low and middle-income countries: A systematic review. PLoS One 2022; 17:e0265536. [PMID: 35358213 PMCID: PMC8970501 DOI: 10.1371/journal.pone.0265536] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 03/03/2022] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND The presence of harmful environmental exposures, which disproportionately affects low-and-middle income countries (LMICs), contributes to >25% of deaths and diseases worldwide and detrimentally affects child neurodevelopment. Few resources succinctly summarize the existing literature on this topic. Our objective is to systematically review and characterize the evidence regarding the relationship between heavy metals and neurodevelopment of children in LMICs. METHODS We conducted a medical librarian-curated search on multiple online databases to identify articles that included individuals <18 years living in a LMIC, quantitatively measured exposure to a heavy metal (either prenatal or postnatal), and used a standardized measurement of neurodevelopment (i.e. cognitive, language, motor, and behavior). Reviews, editorials, or case studies were excluded. Results were analyzed qualitatively, and quality was assessed. RESULTS Of the 18,043 screened articles, 298 full-text articles were reviewed, and 100 articles met inclusion criteria. The included studies represented data from 19 LMICs, only one of which was classified as a low-income country. Ninety-four percent of postnatal lead and all postnatal manganese studies showed a negative association with metal exposure and neurodevelopment, which were the strongest relationships among the metals studied. Postnatal exposure of mercury was associated with poor neurodevelopment in only half of studies. Limited data on postnatal arsenic and cadmium suggests an association with worse neurodevelopment. Findings were mixed for prenatal arsenic and lead, although some evidence supports that the neurotoxicity of lead was amplified in the presence of manganese. CONCLUSIONS AND POTENTIAL IMPACT We found that lead and manganese appear to consistently have a detrimental effect on the neurodevelopment of children, and more evidence is needed for mercury, arsenic, and cadmium. Better characterization of these effects can motivate and inform prioritization of much needed international policies and programs to reduce heavy metal exposures for young children within LMICs.
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Affiliation(s)
- Yi Yan Heng
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Iqra Asad
- School of Science, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana, United States of America
| | - Bailey Coleman
- School of Health and Human Sciences, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana, United States of America
| | - Laura Menard
- Ruth Lilly Medical Library, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Sarah Benki-Nugent
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
| | - Faridah Hussein Were
- Department of Chemistry, College of Biological and Physical Sciences of the University of Nairobi, Nairobi, Kenya
| | - Catherine J. Karr
- Department of Environmental and Occupational Health Sciences, Department of Pediatrics, University of Washington, Seattle, Washington, United States of America
| | - Megan S McHenry
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
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Kupnicka P, Kojder K, Metryka E, Kapczuk P, Jeżewski D, Gutowska I, Goschorska M, Chlubek D, Baranowska-Bosiacka I. Morphine-element interactions - The influence of selected chemical elements on neural pathways associated with addiction. J Trace Elem Med Biol 2020; 60:126495. [PMID: 32179426 DOI: 10.1016/j.jtemb.2020.126495] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 02/17/2020] [Accepted: 03/05/2020] [Indexed: 02/06/2023]
Abstract
Addiction is a pressing social problem worldwide and opioid dependence can be considered the strongest and most difficult addiction to treat. Mesolimbic and mesocortical dopaminergic pathways play an important role in modulation of cognitive processes and decision making and, therefore, changes in dopamine metabolism are considered the central basis for the development of dependence. Disturbances caused by excesses or deficiency of certain elements have a significant impact on the functioning of the central nervous system (CNS) both in physiological conditions and in pathology and can affect the cerebral reward system and therefore, may modulate processes associated with the development of addiction. In this paper we review the mechanisms of interactions between morphine and zinc, manganese, chromium, cadmium, lead, fluoride, their impact on neural pathways associated with addiction, and on antinociception and morphine tolerance and dependence.
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Affiliation(s)
- Patrycja Kupnicka
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, Powstańców Wlkp. 72, 70-111, Szczecin, Poland
| | - Klaudyna Kojder
- Department of Anaesthesiology and Intensive Care, Pomeranian Medical University in Szczecin, Unii Lubelskiej 1, 71-252, Szczecin, Poland.
| | - Emilia Metryka
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, Powstańców Wlkp. 72, 70-111, Szczecin, Poland
| | - Patrycja Kapczuk
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, Powstańców Wlkp. 72, 70-111, Szczecin, Poland
| | - Dariusz Jeżewski
- Department of Applied Neurocognitive Science, Pomeranian Medical University in Szczecin, Unii Lubelskiej 1, 71-252, Szczecin, Poland
| | - Izabela Gutowska
- Department of Biochemistry and Human Nutrition, Pomeranian Medical University in Szczecin, Broniewskiego 24, 71-460, Szczecin, Poland
| | - Marta Goschorska
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, Powstańców Wlkp. 72, 70-111, Szczecin, Poland
| | - Dariusz Chlubek
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, Powstańców Wlkp. 72, 70-111, Szczecin, Poland
| | - Irena Baranowska-Bosiacka
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, Powstańców Wlkp. 72, 70-111, Szczecin, Poland
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Perng W, Tamayo-Ortiz M, Tang L, Sánchez BN, Cantoral A, Meeker JD, Dolinoy DC, Roberts EF, Martinez-Mier EA, Lamadrid-Figueroa H, Song PXK, Ettinger AS, Wright R, Arora M, Schnaas L, Watkins DJ, Goodrich JM, Garcia RC, Solano-Gonzalez M, Bautista-Arredondo LF, Mercado-Garcia A, Hu H, Hernandez-Avila M, Tellez-Rojo MM, Peterson KE. Early Life Exposure in Mexico to ENvironmental Toxicants (ELEMENT) Project. BMJ Open 2019; 9:e030427. [PMID: 31455712 PMCID: PMC6720157 DOI: 10.1136/bmjopen-2019-030427] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 07/23/2019] [Accepted: 07/25/2019] [Indexed: 11/17/2022] Open
Abstract
PURPOSE The Early Life Exposure in Mexico to ENvironmental Toxicants (ELEMENT) Project is a mother-child pregnancy and birth cohort originally initiated in the mid-1990s to explore: (1) whether enhanced mobilisation of lead from maternal bone stores during pregnancy poses a risk to fetal and subsequent offspring neurodevelopment; and (2) whether maternal calcium supplementation during pregnancy and lactation can suppress bone lead mobilisation and mitigate the adverse effects of lead exposure on offspring health and development. Through utilisation of carefully archived biospecimens to measure other prenatal exposures, banking of DNA and rigorous measurement of a diverse array of outcomes, ELEMENT has since evolved into a major resource for research on early life exposures and developmental outcomes. PARTICIPANTS n=1643 mother-child pairs sequentially recruited (between 1994 and 2003) during pregnancy or at delivery from maternity hospitals in Mexico City, Mexico. FINDINGS TO DATE Maternal bone (eg, patella, tibia) is an endogenous source for fetal lead exposure due to mobilisation of stored lead into circulation during pregnancy and lactation, leading to increased risk of miscarriage, low birth weight and smaller head circumference, and transfer of lead into breastmilk. Daily supplementation with 1200 mg of elemental calcium during pregnancy and lactation reduces lead resorption from maternal bone and thereby, levels of circulating lead. Beyond perinatal outcomes, early life exposure to lead is associated with neurocognitive deficits, behavioural disorders, higher blood pressure and lower weight in offspring during childhood. Some of these relationships were modified by dietary factors; genetic polymorphisms specific for iron, folate and lipid metabolism; and timing of exposure. Research has also expanded to include findings published on other toxicants such as those associated with personal care products and plastics (eg, phthalates, bisphenol A), other metals (eg, mercury, manganese, cadmium), pesticides (organophosphates) and fluoride; other biomarkers (eg, toxicant levels in plasma, hair and teeth); other outcomes (eg, sexual maturation, metabolic syndrome, dental caries); and identification of novel mechanisms via epigenetic and metabolomics profiling. FUTURE PLANS As the ELEMENT mothers and children age, we plan to (1) continue studying the long-term consequences of toxicant exposure during the perinatal period on adolescent and young adult outcomes as well as outcomes related to the original ELEMENT mothers, such as their metabolic and bone health during perimenopause; and (2) follow the third generation of participants (children of the children) to study intergenerational effects of in utero exposures. TRIAL REGISTRATION NUMBER NCT00558623.
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Affiliation(s)
- Wei Perng
- Department of Epidemiology, Colorado School of Public Health, University of Colorado Denver Anschutz Medical Center, Aurora, Colorado, USA
- Department of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA
- Lifecourse Epidemiology of Adiposity and Diabetes (LEAD) Center, Colorado School of Public Health, University of Colorado Denver Anschutz Medical Center, Aurora, Colorado, USA
| | - Marcela Tamayo-Ortiz
- National Council of Science and Technology, National Institute of Public Health, Mexico City, Mexico
| | - Lu Tang
- Department of Biostatistics, University of Michigan School of Public Health, Ann Arbor, Michigan, USA
| | - Brisa N Sánchez
- Department of Biostatistics, University of Michigan School of Public Health, Ann Arbor, Michigan, USA
| | - Alejandra Cantoral
- National Council of Science and Technology, National Institute of Public Health, Mexico City, Mexico
| | - John D Meeker
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA
| | - Dana C Dolinoy
- Department of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA
- Center for Human Growth and Development, University of Michigan, Ann Arbor, MI, United States
| | - Elizabeth F Roberts
- Department of Anthropology, University of Michigan, Ann Arbor, Michigan, USA
| | - Esperanza Angeles Martinez-Mier
- Department of Cariology, Operative Dentistry and Dental Public Health, Indiana University School of Dentistry, Indianapolis, Indiana, USA
| | | | - Peter X K Song
- Department of Biostatistics, University of Michigan School of Public Health, Ann Arbor, Michigan, USA
| | - Adrienne S Ettinger
- Department of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA
| | - Robert Wright
- Department of Environmental Medicine & Public Health, Icahn School of Medicine at Mount Sinai Hospital, New York, New York, USA
| | - Manish Arora
- Department of Environmental Medicine & Public Health, Icahn School of Medicine at Mount Sinai Hospital, New York, New York, USA
| | - Lourdes Schnaas
- Division of Research in Community Interventions, Instituto Nacional de Perinatologia, Mexico City, Mexico
| | - Deborah J Watkins
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA
| | - Jaclyn M Goodrich
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA
| | - Robin C Garcia
- Department of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA
| | - Maritsa Solano-Gonzalez
- Center for Nutrition and Health Research, National Institute of Public Health, Cuernavaca, Mexico
| | | | - Adriana Mercado-Garcia
- Center for Nutrition and Health Research, National Institute of Public Health, Cuernavaca, Mexico
| | - Howard Hu
- Department of Environmental and Occupational Health, University of Washington School of Public Health, Seattle, Washington, USA
| | - Mauricio Hernandez-Avila
- Dirección de Prestaciones Económicas y Sociales, Mexican Institute of Social Security, Mexico City, Mexico
| | - Martha Maria Tellez-Rojo
- Center for Nutrition and Health Research, National Institute of Public Health, Cuernavaca, Mexico
| | - Karen E Peterson
- Department of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA
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8
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Cui Y, Zhang B, Ma J, Wang Y, Zhao L, Hou C, Yu J, Zhao Y, Zhang Z, Nie J, Gao T, Zhou G, Liu H. Dopamine receptor D2 gene polymorphism, urine fluoride, and intelligence impairment of children in China: A school-based cross-sectional study. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 165:270-277. [PMID: 30205328 DOI: 10.1016/j.ecoenv.2018.09.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 08/27/2018] [Accepted: 09/02/2018] [Indexed: 06/08/2023]
Abstract
OBJECTIVE We aimed to study the association of urine fluoride with intelligence quotient (IQ) in children with a careful consideration of up to 30 potential confounding factors as well as possible heterogeneity of the relation between urine fluoride levels and IQ scores across children with different dopamine receptor-2 (DRD2) Taq 1A genotypes (CC, CT, and TT). METHODS A school-based cross-sectional study design was applied. A total of 323 children (2014-2015, 7-12 years old) were enrolled from four schools in both historical endemic and non-endemic areas of fluorosis in Tianjin of China using a cluster sampling method. Urine fluoride levels and age-specific IQ scores in children were measured at the enrollment. Polymerase chain reaction-restriction fragment length polymorphism methods were used to genotype DRD2 Taq 1A polymorphism with genomic DNA isolated from whole blood collected at the enrollment. Multiple linear regression models were applied to evaluate the relationship between urine fluoride levels and IQ scores overall and within the DRD2 Taq 1A SNP = CC/CT and TT subgroups. Model robustness was tested through bootstrap, sensitivity analysis, and cross-validation techniques. A safety threshold of urine fluoride levels for IQ impairment was determined in the subgroup TT. RESULTS In overall participants, the DRD2 Taq 1A polymorphism itself was not related to IQ scores in children who had a high level of urine fluoride. In the CC/CT subgroup, urine fluoride levels and IQ scores in children were unrelated (adjusted β (95% confidence interval (CI)) = - 1.59 (- 4.24, 1.05), p = 0.236). Among the participants carrying the TT genotype, there was a strong and robust negative linear relationship between log-urine fluoride and IQ scores in children (adjusted β (95% CI) = - 12.31 (- 18.69, - 5.94), p < 0.001). Urine fluoride levels had a stronger association with IQ in children carrying the TT genotype (adjusted β = - 12.31, bootstrapped standard error (SE) = 1.28), compared to that in overall participants (adjusted β = - 2.47, bootstrapped SE = 3.75) (Z = 2.483 and bootstrapped p = 0.007). The safety threshold of urine fluoride levels in the subgroup TT was 1.73 mg/L (95% CI = (1.51, 1.97) (mg/L)). CONCLUSIONS There is heterogeneity in the relation between urine fluoride and IQ across children carrying different DRD2 Taq 1A genotypes. Large-scale epidemiological studies are needed to confirm our findings.
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Affiliation(s)
- Yushan Cui
- Tianjin Centers for Disease Control and Prevention, 6 Huayue Road, Hedong District,Tianjin 300011, PR China
| | - Bin Zhang
- School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin 300070, PR China
| | - Jing Ma
- Tianjin Cardiovascular Institute, Tianjin Chest Hospital, 261 Taierzhuang south road, Jinnan District, Tianjin 300050, PR China
| | - Yang Wang
- Tianjin Centers for Disease Control and Prevention, 6 Huayue Road, Hedong District,Tianjin 300011, PR China
| | - Liang Zhao
- Tianjin Centers for Disease Control and Prevention, 6 Huayue Road, Hedong District,Tianjin 300011, PR China
| | - Changchun Hou
- Tianjin Centers for Disease Control and Prevention, 6 Huayue Road, Hedong District,Tianjin 300011, PR China
| | - Jingwen Yu
- School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin 300070, PR China
| | - Yang Zhao
- School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin 300070, PR China
| | - Zushan Zhang
- School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin 300070, PR China
| | - Junyan Nie
- School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin 300070, PR China
| | - Tongning Gao
- School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin 300070, PR China
| | - Guoli Zhou
- Biomedical Research Informatics Core (BRIC), Clinical and Translational Sciences Institute (CTSI), Michigan State University, 909 Fee Road, East Lansing, MI 48824, USA.
| | - Hongliang Liu
- Tianjin Centers for Disease Control and Prevention, 6 Huayue Road, Hedong District,Tianjin 300011, PR China; School of Public Health, Tianjin Medical University, 22 Qixiangtai Road, Heping District, Tianjin 300070, PR China.
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Prenatal lead exposure modifies the association of maternal self-esteem with child adaptive ability. Int J Hyg Environ Health 2018; 222:68-75. [PMID: 30146178 DOI: 10.1016/j.ijheh.2018.08.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 08/08/2018] [Accepted: 08/10/2018] [Indexed: 10/28/2022]
Abstract
BACKGROUND A child's adaptive ability is important for personal career and social development. Maternal self-esteem may help shape a child's behavior. This study aims to investigate whether maternal self-esteem measured when their children were toddlers predicts their children's adaptive skills at school age, and whether prenatal lead exposure modifies such a relationship. METHODS We assessed prenatal lead exposure using cord blood lead and maternal bone lead around delivery (tibia and patella lead measured in vivo by K-x-ray-fluorescence) among 192 mother-child pairs investigated in Mexico from 1994 to 2011. Maternal self-esteem was measured using the Coopersmith-Self-esteem-Inventory when children were 2 years old. When children were 7-to-15 years old, we measured children's blood lead levels and administered the 2nd edition of Behavior-Assessment-System-for-Children (BASC-2) parent-rating-scales (PRS) and Self-Reports of Personality (SRP) to evaluate children's adaptive skills. RESULTS Median (P25, P75) values for maternal patella and tibia lead, cord blood lead and children's current blood lead levels were 12.6 (3.2, 21.7) μg/g, 10.2 (4.1, 16.0) μg/g, 5.5 (3.5, 8.1) μg/dL and 2.7 (2.0, 4.0) μg/dL, respectively. In adjusted models, increased maternal self-esteem was associated with increased adaptive T-scores on the BASC-2 PRS and SRP scales. This relationship was weaker in high prenatal lead-exposure groups (high cord blood lead or patella lead groups, P25P100) compared with low prenatal lead-exposure (low cord blood lead or patella lead groups, P1P25) groups (P-interaction values < 0.10). No significant interactions between maternal tibia lead and self-esteem on children's adaptive T-scores were observed (P-interaction values > 0.10). CONCLUSIONS Toddlers of mothers with high (vs. low) self-esteem have better adaptive abilities when they are of school-age. Prenatal lead exposure may attenuate or eliminate this positive association.
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Interaction between DRD2 and lead exposure on the cortical thickness of the frontal lobe in youth with attention-deficit/hyperactivity disorder. Prog Neuropsychopharmacol Biol Psychiatry 2018; 82:169-176. [PMID: 29169998 DOI: 10.1016/j.pnpbp.2017.11.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Revised: 11/10/2017] [Accepted: 11/18/2017] [Indexed: 11/23/2022]
Abstract
BACKGROUND The dopamine receptor D2 receptor (DRD2) gene and lead exposure are both thought to contribute to the pathophysiology of attention-deficit/hyperactivity disorder (ADHD). ADHD is characterized by delay in brain maturation, most prominent in the prefrontal cortex (PFC). The D2 receptor is also mainly located in the PFC, and animal studies show that lead exposure affects the dopaminergic system of the frontal lobe, indicating an overlap in neural correlates of ADHD, DRD2, and lead exposure. We examined the interaction effects of DRD2 rs1800497 and lead exposure on the cortical thickness of the frontal lobe in patients with ADHD. METHODS A 1:1 age- and gender-matched sample of 75 participants with ADHD and 75 healthy participants was included in the analysis. The interaction effects of DRD2 and lead exposure on the cortical thickness of 12 regions of interest in the frontal lobe were examined by multivariable linear regression analyses. RESULTS When we investigated the DRD2×lead effects in the ADHD and HC groups separately, significant DRD2×lead effects were found in the ADHD group, but not in the healthy control group in multiple ROIs of the frontal lobe. There was a significant negative correlation between the cortical thickness of the right superior frontal gyrus and inattention scores. CONCLUSIONS The present findings demonstrated significant interaction effects of DRD2 and lead exposure on the cortical thickness of the frontal lobe in ADHD. Replication studies with larger sample sizes, using a prospective design, are warranted to confirm these findings.
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Bashash M, Thomas D, Hu H, Martinez-Mier EA, Sanchez BN, Basu N, Peterson KE, Ettinger AS, Wright R, Zhang Z, Liu Y, Schnaas L, Mercado-García A, Téllez-Rojo MM, Hernández-Avila M. Prenatal Fluoride Exposure and Cognitive Outcomes in Children at 4 and 6-12 Years of Age in Mexico. ENVIRONMENTAL HEALTH PERSPECTIVES 2017; 125:097017. [PMID: 28937959 PMCID: PMC5915186 DOI: 10.1289/ehp655] [Citation(s) in RCA: 126] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 05/08/2017] [Accepted: 05/09/2017] [Indexed: 05/22/2023]
Abstract
BACKGROUND Some evidence suggests that fluoride may be neurotoxic to children. Few of the epidemiologic studies have been longitudinal, had individual measures of fluoride exposure, addressed the impact of prenatal exposures or involved more than 100 participants. OBJECTIVE Our aim was to estimate the association of prenatal exposure to fluoride with offspring neurocognitive development. METHODS We studied participants from the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) project. An ion-selective electrode technique was used to measure fluoride in archived urine samples taken from mothers during pregnancy and from their children when 6-12 y old, adjusted for urinary creatinine and specific gravity, respectively. Child intelligence was measured by the General Cognitive Index (GCI) of the McCarthy Scales of Children's Abilities at age 4 and full scale intelligence quotient (IQ) from the Wechsler Abbreviated Scale of Intelligence (WASI) at age 6-12. RESULTS We had complete data on 299 mother-child pairs, of whom 287 and 211 had data for the GCI and IQ analyses, respectively. Mean (SD) values for urinary fluoride in all of the mothers (n=299) and children with available urine samples (n=211) were 0.90 (0.35) mg/L and 0.82 (0.38) mg/L, respectively. In multivariate models we found that an increase in maternal urine fluoride of 0.5mg/L (approximately the IQR) predicted 3.15 (95% CI: -5.42, -0.87) and 2.50 (95% CI -4.12, -0.59) lower offspring GCI and IQ scores, respectively. CONCLUSIONS In this study, higher prenatal fluoride exposure, in the general range of exposures reported for other general population samples of pregnant women and nonpregnant adults, was associated with lower scores on tests of cognitive function in the offspring at age 4 and 6-12 y. https://doi.org/10.1289/EHP655.
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Affiliation(s)
- Morteza Bashash
- Dalla Lana School of Public Health, University of Toronto , Toronto, Ontario, Canada
| | - Deena Thomas
- University of Michigan School of Public Health , Ann Arbor, Michigan, USA
| | - Howard Hu
- Dalla Lana School of Public Health, University of Toronto , Toronto, Ontario, Canada
| | - E Angeles Martinez-Mier
- Indiana University School of Dentistry, Indiana University-Purdue University Indianapolis , Indianapolis, Indiana, USA
| | - Brisa N Sanchez
- University of Michigan School of Public Health , Ann Arbor, Michigan, USA
| | - Niladri Basu
- Faculty of Agricultural and Environmental Sciences, McGill University , Montreal, Quebec, Canada
| | - Karen E Peterson
- University of Michigan School of Public Health , Ann Arbor, Michigan, USA
- Center for Human Growth and Development, University of Michigan , Ann Arbor, Michigan, USA
- Harvard T.H. Chan School of Public Health , Boston, Massachusetts, USA
| | | | - Robert Wright
- Icahn School of Medicine at Mount Sinai , New York, New York, USA
| | - Zhenzhen Zhang
- University of Michigan School of Public Health , Ann Arbor, Michigan, USA
| | - Yun Liu
- University of Michigan School of Public Health , Ann Arbor, Michigan, USA
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Bischoff AR, Pokhvisneva I, Léger É, Gaudreau H, Steiner M, Kennedy JL, O’Donnell KJ, Diorio J, Meaney MJ, Silveira PP. Dynamic interaction between fetal adversity and a genetic score reflecting dopamine function on developmental outcomes at 36 months. PLoS One 2017; 12:e0177344. [PMID: 28505190 PMCID: PMC5432105 DOI: 10.1371/journal.pone.0177344] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 04/26/2017] [Indexed: 12/27/2022] Open
Abstract
Background Fetal adversity, evidenced by poor fetal growth for instance, is associated with increased risk for several diseases later in life. Classical cut-offs to characterize small (SGA) and large for gestational age (LGA) newborns are used to define long term vulnerability. We aimed at exploring the possible dynamism of different birth weight cut-offs in defining vulnerability in developmental outcomes (through the Bayley Scales of Infant and Toddler Development), using the example of a gene vs. fetal adversity interaction considering gene choices based on functional relevance to the studied outcome. Methods 36-month-old children from an established prospective birth cohort (Maternal Adversity, Vulnerability, and Neurodevelopment) were classified according to birth weight ratio (BWR) (SGA ≤0.85, LGA >1.15, exploring a wide range of other cut-offs) and genotyped for polymorphisms associated with dopamine signaling (TaqIA-A1 allele, DRD2-141C Ins/Ins, DRD4 7-repeat, DAT1-10- repeat, Met/Met-COMT), composing a score based on the described function, in which hypofunctional variants received lower scores. Results There were 251 children (123 girls and 128 boys). Using the classic cut-offs (0.85 and 1.15), there were no statistically significant interactions between the neonatal groups and the dopamine genetic score. However, when changing the cut-offs, it is possible to see ranges of BWR that could be associated with vulnerability to poorer development according to the variation in the dopamine function. Conclusion The classic birth weight cut-offs to define SGA and LGA newborns should be seen with caution, as depending on the outcome in question, the protocols for long-term follow up could be either too inclusive—therefore most costly, or unable to screen true vulnerabilities—and therefore ineffective to establish early interventions and primary prevention.
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Affiliation(s)
- Adrianne R. Bischoff
- Department of Pediatrics, Division of Neonatology, University of Toronto and the Hospital for Sick Children, Toronto, Ontario, Canada
| | - Irina Pokhvisneva
- Ludmer Centre for Neuroinformatics and Mental Health, Douglas Mental Health University Institute, McGill University, Douglas Mental Health University Institute, Montreal, Quèbec, Canada
| | - Étienne Léger
- Ludmer Centre for Neuroinformatics and Mental Health, Douglas Mental Health University Institute, McGill University, Douglas Mental Health University Institute, Montreal, Quèbec, Canada
| | - Hélène Gaudreau
- Ludmer Centre for Neuroinformatics and Mental Health, Douglas Mental Health University Institute, McGill University, Douglas Mental Health University Institute, Montreal, Quèbec, Canada
| | - Meir Steiner
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada
| | - James L. Kennedy
- Department of Psychiatry, University of Toronto and Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Kieran J. O’Donnell
- Ludmer Centre for Neuroinformatics and Mental Health, Douglas Mental Health University Institute, McGill University, Douglas Mental Health University Institute, Montreal, Quèbec, Canada
- Child and Brain Development Program, Canadian Institute for Advanced Research (CIFAR), Toronto, Ontario, Canada
- Department of Psychiatry, McGill University, Montreal, Quebec, Canada
| | - Josie Diorio
- Ludmer Centre for Neuroinformatics and Mental Health, Douglas Mental Health University Institute, McGill University, Douglas Mental Health University Institute, Montreal, Quèbec, Canada
| | - Michael J. Meaney
- Ludmer Centre for Neuroinformatics and Mental Health, Douglas Mental Health University Institute, McGill University, Douglas Mental Health University Institute, Montreal, Quèbec, Canada
- Department of Psychiatry, McGill University, Montreal, Quebec, Canada
| | - Patrícia P. Silveira
- Ludmer Centre for Neuroinformatics and Mental Health, Douglas Mental Health University Institute, McGill University, Douglas Mental Health University Institute, Montreal, Quèbec, Canada
- Department of Psychiatry, McGill University, Montreal, Quebec, Canada
- * E-mail:
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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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Tao Y, Sánchez BN, Mukherjee B. Latent variable models for gene-environment interactions in longitudinal studies with multiple correlated exposures. Stat Med 2015; 34:1227-41. [PMID: 25545894 PMCID: PMC4355187 DOI: 10.1002/sim.6401] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 12/05/2014] [Accepted: 12/08/2014] [Indexed: 12/18/2022]
Abstract
Many existing cohort studies designed to investigate health effects of environmental exposures also collect data on genetic markers. The Early Life Exposures in Mexico to Environmental Toxicants project, for instance, has been genotyping single nucleotide polymorphisms on candidate genes involved in mental and nutrient metabolism and also in potentially shared metabolic pathways with the environmental exposures. Given the longitudinal nature of these cohort studies, rich exposure and outcome data are available to address novel questions regarding gene-environment interaction (G × E). Latent variable (LV) models have been effectively used for dimension reduction, helping with multiple testing and multicollinearity issues in the presence of correlated multivariate exposures and outcomes. In this paper, we first propose a modeling strategy, based on LV models, to examine the association between repeated outcome measures (e.g., child weight) and a set of correlated exposure biomarkers (e.g., prenatal lead exposure). We then construct novel tests for G × E effects within the LV framework to examine effect modification of outcome-exposure association by genetic factors (e.g., the hemochromatosis gene). We consider two scenarios: one allowing dependence of the LV models on genes and the other assuming independence between the LV models and genes. We combine the two sets of estimates by shrinkage estimation to trade off bias and efficiency in a data-adaptive way. Using simulations, we evaluate the properties of the shrinkage estimates, and in particular, we demonstrate the need for this data-adaptive shrinkage given repeated outcome measures, exposure measures possibly repeated and time-varying gene-environment association.
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Affiliation(s)
- Yebin Tao
- Department of Biostatistics, University of Michigan, Ann Arbor, Michigan, 48109, U.S.A
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15
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Liu L, Xu X, Yekeen TA, Lin K, Li W, Huo X. Assessment of association between the dopamine D2 receptor (DRD2) polymorphism and neurodevelopment of children exposed to lead. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:1786-93. [PMID: 24469773 DOI: 10.1007/s11356-014-2565-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 01/16/2014] [Indexed: 02/05/2023]
Abstract
The mechanism of lead (Pb) neurotoxicity has not been illustrated over the years. People pay more attention to dopaminergic neurotransmission, specifically dopamine receptor-2 (DRD2) Taq IA polymorphism, but no consensus has been reached. A total of 258 three-year-old children in Guiyu (exposed group) and Nanao (reference group), China were examined and their concentrations of blood lead (BPb) were determined. Cognitive and language scores of children were assessed using the Bayley Scales of Infant Development, third edition (BSID-III). Genotyping for the DRD2 polymorphism was carried out using a polymerase chain reaction (PCR) re-sequencing platform. The logistic stepwise regression analysis and stepwise regression analysis was used to explore associations among lead, neurodevelopment of children, and DRD2 Taq IA categories. Median values of Pb in Guiyu was higher than that of the reference group (11.30 ± 5.38 μg/dL vs. 5.77 ± 2.51 μg/dL, P < 0.001). Compared with the reference group, children from e-waste exposed area have lower cognitive scale scores (100 ± 25 vs 120 ± 20, P < 0.001) and lower language scale scores (99.87 ± 7.52 vs 111.39 ± 7.02, P < 0.001). The three kinds of genotype, A1/A1, A1/A2, and A2/A2, had no significant influences on BPb, cognitive scores and language scores (P > 0.05). Exposure of inhabitants, especially children to Pb from informal e-waste recycling activities might have contributed to higher levels of BPb and reduced cognitive and language scores observed in local children, however, the result obtained showed no significant association between DRD2 polymorphism and neurodevelopment of children exposed to lead.
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Affiliation(s)
- Lian Liu
- Laboratory of Environmental Medicine and Developmental Toxicology, and Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou, 515041, Guangdong, People's Republic of China
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Chang J, Kueon C, Kim J. Influence of lead on repetitive behavior and dopamine metabolism in a mouse model of iron overload. Toxicol Res 2015; 30:267-76. [PMID: 25584146 PMCID: PMC4289927 DOI: 10.5487/tr.2014.30.4.267] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 09/30/2014] [Accepted: 10/06/2014] [Indexed: 12/12/2022] Open
Abstract
Exposures to lead (Pb) are associated with neurological problems including psychiatric disorders and impaired learning and memory. Pb can be absorbed by iron transporters, which are up-regulated in hereditary hemochromatosis, an iron overload disorder in which increased iron deposition in various parenchymal organs promote metal-induced oxidative damage. While dysfunction in HFE (High Fe) gene is the major cause of hemochromatosis, the transport and toxicity of Pb in Hfe-related hemochromatosis are largely unknown. To elucidate the relationship between HFE gene dysfunction and Pb absorption, H67D knock-in Hfe-mutant and wild-type mice were given drinking water containing Pb 1.6 mg/ml ad libitum for 6 weeks and examined for behavioral phenotypes using the nestlet-shredding and marble-burying tests. Latency to nestlet-shredding in Pb-treated wild-type mice was prolonged compared with non-exposed wild-types (p < 0.001), whereas Pb exposure did not alter shredding latency in Hfe-mutant mice. In the marble-burying test, Hfe-mutant mice showed an increased number of marbles buried compared with wild-type mice (p = 0.002), indicating more repetitive behavior upon Hfe mutation. Importantly, Pb-exposed wild-type mice buried more marbles than non-exposed wild-types, whereas the number of marbles buried by Hfe-mutant mice did not change whether or not exposed to Pb. These results suggest that Hfe mutation could normalize Pb-induced behavioral alteration. To explore the mechanism of repetitive behavior caused by Pb, western blot analysis was conducted for proteins involved in brain dopamine metabolism. The levels of tyrosine hydroxylase and dopamine transporter increased upon Pb exposure in both genotypes, whereas Hfe-mutant mice displayed down-regulation of the dopamine transporter and dopamine D1 receptor with D2 receptor elevated. Taken together, our data support the idea that both Pb exposure and Hfe mutation increase repetitive behavior in mice and further suggest that these behavioral changes could be associated with altered dopaminergic neurotransmission, providing a therapeutic basis for psychiatric disorders caused by Pb toxicity.
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Affiliation(s)
- JuOae Chang
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, MA 02115, USA
| | - Chojin Kueon
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, MA 02115, USA
| | - Jonghan Kim
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, MA 02115, USA
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Crump KS, Van Landingham C, Bowers TS, Cahoy D, Chandalia JK. A statistical reevaluation of the data used in the Lanphear et al. ( 2005 ) pooled-analysis that related low levels of blood lead to intellectual deficits in children. Crit Rev Toxicol 2014; 43:785-99. [PMID: 24040996 DOI: 10.3109/10408444.2013.832726] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
A pooled-analysis by Lanphear et al. (2005) of seven cohort studies of the association between blood lead (BPb) concentrations in children and measures of their intelligence concluded that "environmental lead exposure in children who have maximal blood lead levels <7.5 μg/dL is associated with intellectual deficits." This study has played a prominent role in shaping the public understanding of the effects upon children's IQ of low BPb exposures (e.g., BPb ≤ 10 μg/dL). Here we present a reanalysis of the data used by Lanphear et al. to evaluate the robustness of their conclusions. Our analysis differed from that of Lanphear et al. primarily in how we controlled for non-lead variables (allowing a number of them to be site-specific), how we defined summary measures of BPb exposure, and in how we decided which BPb measures and transformations best modeled the data. We also reproduced the Lanphear et al. analysis. Although we found some small errors and questionable decisions by Lanphear et al. that, taken alone, could cause doubt in their conclusions, our reanalysis tended to support their conclusions. We concluded that there was statistical evidence that the exposure-response is non-linear over the full range of BPb evaluated in these studies, which implies that, for a given increase in blood lead, the associated IQ decrement is greater at lower BPb levels. However at BPb below 10 µg/dL, the exposure-response is adequately modeled as linear. We also found statistical evidence for an association with IQ among children who had maximal measured BPb levels ≤7 μg/dL, and concurrent BPb levels as low as ≤5 μg/dL.
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Blum K, Schoenthaler SJ, Oscar-Berman M, Giordano J, Madigan MA, Braverman ER, Han D. Drug abuse relapse rates linked to level of education: can we repair hypodopaminergic-induced cognitive decline with nutrient therapy? PHYSICIAN SPORTSMED 2014; 42:130-45. [PMID: 24875980 DOI: 10.3810/psm.2014.05.2065] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
It is well known that athletes and other individuals who have suffered painful injuries are at increased risk for all reward deficiency syndrome (RDS) behaviors, including substance use disorder (SUD). Comparing patient demographics and relapse rates in chemical dependence programs is pertinent because demographics may affect outcomes. Increased risk for relapse and lower academic achievement were found to have a significant association in recent outcome data from a holistic treatment center (HTC) located in North Miami Beach, FL. Relapse outcomes from the Drug Addiction Treatment Outcome Study (DATOS; n = 1738) and HTC (n = 224) were compared for a 12-month period. Post-discharge relapse was reported by 26% of HTC patients and 58% of patients in DATOS. When broken out by education level-less than high school, high school diploma, college degree, and graduate degree-HTC patient relapse was 50%, 36%, 33%, and 16%, respectively, and demonstrated an inverse linear association (F = 5.702; P = 0.017). Looking at DATOS patient relapse rates broken down by educational grades/years completed, patients who attended school between 7th grade and 4 years of college also demonstrated an inverse linear association (F = 5.563; P = 0.018). Additionally, the lowest performers, patients who reported their academic performance as "not so good," had the highest relapse (F = 4.226; P = 0.04). Albeit certain limitations, compared with DATOS patients, HTC patients produced significantly larger net differences in relapse rates (X 2 = 84.09; P = 0.0001), suggesting that other variables, such as the treatment model may also affect patient relapse. Our results implicate the use of vitamin and mineral supplements coupled with a well-researched natural dopamine agonist nutrient therapy; both have been shown to improve cognition and behavior, and thus academic achievement. That relapse is highest among addicts who have less education and who report lower grades is a factor that can be useful when considering treatment type and controlled for when comparing treatment outcomes.
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Affiliation(s)
- Kenneth Blum
- Department of Psychiatry and McKnight Brain Institute, University of Florida College of Medicine, Gainesville, FL.
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Horton LM, Mortensen ME, Iossifova Y, Wald MM, Burgess P. What do we know of childhood exposures to metals (arsenic, cadmium, lead, and mercury) in emerging market countries? Int J Pediatr 2013; 2013:872596. [PMID: 23365584 PMCID: PMC3556434 DOI: 10.1155/2013/872596] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 11/17/2012] [Accepted: 11/17/2012] [Indexed: 12/28/2022] Open
Abstract
Arsenic, cadmium, lead, and mercury present potential health risks to children who are exposed through inhalation or ingestion. Emerging Market countries experience rapid industrial development that may coincide with the increased release of these metals into the environment. A literature review was conducted for English language articles from the 21st century on pediatric exposures to arsenic, cadmium, lead, and mercury in the International Monetary Fund's (IMF) top 10 Emerging Market countries: Brazil, China, India, Indonesia, Mexico, Poland, Russia, South Korea, Taiwan, and Turkey. Seventy-six peer-reviewed, published studies on pediatric exposure to metals met the inclusion criteria. The reported concentrations of metals in blood and urine from these studies were generally higher than US reference values, and many studies identified adverse health effects associated with metals exposure. Evidence of exposure to metals in the pediatric population of these Emerging Market countries demonstrates a need for interventions to reduce exposure and efforts to establish country-specific reference values through surveillance or biomonitoring. The findings from review of these 10 countries also suggest the need for country-specific public health policies and clinician education in Emerging Markets.
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Affiliation(s)
- Lindsey M. Horton
- Office of Science, National Center for Environmental Health and Agency for Toxic Substances and Disease Registry, 4770 Buford Highway, Atlanta, GA 30341, USA
| | - Mary E. Mortensen
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Highway, Atlanta, GA 30341, USA
| | - Yulia Iossifova
- Office of Science, National Center for Environmental Health and Agency for Toxic Substances and Disease Registry, 4770 Buford Highway, Atlanta, GA 30341, USA
| | - Marlena M. Wald
- Office of Science, National Center for Environmental Health and Agency for Toxic Substances and Disease Registry, 4770 Buford Highway, Atlanta, GA 30341, USA
| | - Paula Burgess
- Office of Science, National Center for Environmental Health and Agency for Toxic Substances and Disease Registry, 4770 Buford Highway, Atlanta, GA 30341, USA
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Braun JM, Hoffman E, Schwartz J, Sanchez B, Schnaas L, Mercado-Garcia A, Solano-Gonzalez M, Bellinger DC, Lanphear BP, Hu H, Tellez-Rojo MM, Wright RO, Hernandez-Avila M. Assessing windows of susceptibility to lead-induced cognitive deficits in Mexican children. Neurotoxicology 2012; 33:1040-7. [PMID: 22579785 DOI: 10.1016/j.neuro.2012.04.022] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 04/15/2012] [Accepted: 04/30/2012] [Indexed: 11/19/2022]
Abstract
BACKGROUND The identification of susceptible periods to Pb-induced decrements in childhood cognitive abilities remains elusive. OBJECTIVE To draw inferences about windows of susceptibility using the pattern of associations between serial childhood blood lead (BPb) concentrations and children's cognitive abilities at 4 years of age among 1035 mother-child pairs enrolled in 4 prospective birth cohorts from Mexico City. METHODS Multiple longitudinally collected BPb measurements were obtained from children (1, 2, 3, and 4 years) between 1994 and 2007. Child cognitive abilities were assessed at 4 years using the general cognitive index (GCI) of the McCarthy Scales of Children's Abilities. We used multivariable linear regression to estimate the change in cognitive abilities at 4 years of age with a 10 μg/dL increase in childhood BPb concentrations adjusting for maternal IQ, education, marital status, child sex, breastfeeding duration, and cohort. RESULTS In separate models for each BPb measurement, 2 year BPb concentrations were most strongly associated with reduced GCI scores at 4 years after adjusting for confounders (β: -3.8; 95% confidence interval CI: -6.3, -1.4). Mutual adjustment for other BPb concentrations in a single model resulted in larger, but less precise estimate between 2 year BPb concentrations and GCI scores at 4 years of age (β: -7.1; 95% CI: -12, -2.0). The association between 2 year BPb and GCI was not heterogeneous (p=0.89), but some BPb and GCI associations varied in magnitude and direction across the cohorts. Additional adjustment for child hemoglobin, birth weight, gestational age, gestational BPb concentrations, or test examiner did not change the pattern of associations. CONCLUSIONS Higher BPb concentrations at 2 years of age were most predictive of decreased cognitive abilities among these Mexico City children; however, the observed pattern may be due to exposure, outcome, or cohort related factors. These results may help developing countries more efficiently implement childhood Pb prevention strategies.
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Affiliation(s)
- Joe M Braun
- Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA.
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