title: The human early-life exposome (HELIX): project rationale and design.
abstract: BACKGROUND
  Developmental periods in early life may be particularly vulnerable to impacts of environmental exposures. Human research on this topic has generally focused on single exposure-health effect relationships. The "exposome" concept encompasses the totality of exposures from conception onward, complementing the genome.
  
  
  OBJECTIVE
  The Human Early-Life Exposome (HELIX) project is a new collaborative research project that aims to implement novel exposure assessment and biomarker methods to characterize early-life exposure to multiple environmental factors and associate these with omics biomarkers and child health outcomes, thus characterizing the "early-life exposome." Here we describe the general design of the project.
  
  
  METHODS
  In six existing birth cohort studies in Europe, HELIX will estimate prenatal and postnatal exposure to a broad range of chemical and physical exposures. Exposure models will be developed for the full cohorts totaling 32,000 mother-child pairs, and biomarkers will be measured in a subset of 1,200 mother-child pairs. Nested repeat-sampling panel studies (n = 150) will collect data on biomarker variability, use smartphones to assess mobility and physical activity, and perform personal exposure monitoring. Omics techniques will determine molecular profiles (metabolome, proteome, transcriptome, epigenome) associated with exposures. Statistical methods for multiple exposures will provide exposure-response estimates for fetal and child growth, obesity, neurodevelopment, and respiratory outcomes. A health impact assessment exercise will evaluate risks and benefits of combined exposures.
  
  
  CONCLUSIONS
  HELIX is one of the first attempts to describe the early-life exposome of European populations and unravel its relation to omics markers and health in childhood. As proof of concept, it will form an important first step toward the life-course exposome.
authors.affiliation: Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain.
authors.forename: Martine
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authors.lastname: Vrijheid
authors.forename: Rémy
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authors.lastname: Slama
authors.forename: Oliver
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authors.forename: Leda
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authors.forename: Muireann
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authors.lastname: van den Hazel
authors.forename: Cathrine
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authors.initials: TJ
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authors.forename: Narcis
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authors.lastname: Avellana
authors.forename: Xavier
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authors.lastname: Basagaña
authors.forename: Celine
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authors.lastname: Brochot
authors.forename: Luca
authors.initials: L
authors.lastname: Bucchini
authors.forename: Mariona
authors.initials: M
authors.lastname: Bustamante
authors.forename: Angel
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authors.lastname: Carracedo
authors.forename: Maribel
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authors.lastname: Casas
authors.forename: Xavier
authors.initials: X
authors.lastname: Estivill
authors.forename: Lesley
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authors.lastname: Fairley
authors.forename: Diana
authors.initials: D
authors.lastname: van Gent
authors.forename: Juan R
authors.initials: JR
authors.lastname: Gonzalez
authors.forename: Berit
authors.initials: B
authors.lastname: Granum
authors.forename: Regina
authors.initials: R
authors.lastname: Gražulevičienė
authors.forename: Kristine B
authors.initials: KB
authors.lastname: Gutzkow
authors.forename: Jordi
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authors.forename: Hector C
authors.initials: HC
authors.lastname: Keun
authors.forename: Manolis
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authors.lastname: Kogevinas
authors.forename: Rosemary R C
authors.initials: RR
authors.lastname: McEachan
authors.forename: Helle Margrete
authors.initials: HM
authors.lastname: Meltzer
authors.forename: Eduard
authors.initials: E
authors.lastname: Sabidó
authors.forename: Per E
authors.initials: PE
authors.lastname: Schwarze
authors.forename: Valérie
authors.initials: V
authors.lastname: Siroux
authors.forename: Jordi
authors.initials: J
authors.lastname: Sunyer
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Want
authors.forename: Florence
authors.initials: F
authors.lastname: Zeman
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Nieuwenhuijsen
mesh_terms: D015415:Biomarkers; D002648:Child; D002657:Child Development; D002675:Child, Preschool; D015331:Cohort Studies; D004781:Environmental Exposure / Q000009:adverse effects* / Q000032:analysis* / Q000706:statistics & numerical data; D057890:Epigenomics; D005060:Europe; D005260:Female; D047109:Fetal Development; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D018811:Maternal Exposure / Q000009:adverse effects / Q000706:statistics & numerical data; D055442:Metabolome; D009765:Obesity; D011247:Pregnancy; D020543:Proteome; D059467:Transcriptome
chemical_list: D015415:Biomarkers; D020543:Proteome