title: Small-Magnitude Effect Sizes in Epigenetic End Points are Important in Children's Environmental Health Studies: The Children's Environmental Health and Disease Prevention Research Center's Epigenetics Working Group.
abstract: Characterization of the epigenome is a primary interest for children's environmental health researchers studying the environmental influences on human populations, particularly those studying the role of pregnancy and early-life exposures on later-in-life health outcomes.
  
  
  
  Our objective was to consider the state of the science in environmental epigenetics research and to focus on DNA methylation and the collective observations of many studies being conducted within the Children's Environmental Health and Disease Prevention Research Centers, as they relate to the Developmental Origins of Health and Disease (DOHaD) hypothesis.
  
  
  
  We address the current laboratory and statistical tools available for epigenetic analyses, discuss methods for validation and interpretation of findings, particularly when magnitudes of effect are small, question the functional relevance of findings, and discuss the future for environmental epigenetics research.
  
  
  
  A common finding in environmental epigenetic studies is the small-magnitude epigenetic effect sizes that result from such exposures. Although it is reasonable and necessary that we question the relevance of such small effects, we present examples in which small effects persist and have been replicated across populations and across time. We encourage a critical discourse on the interpretation of such small changes and further research on their functional relevance for children's health.
  
  
  
  The dynamic nature of the epigenome will require an emphasis on future longitudinal studies in which the epigenome is profiled over time, over changing environmental exposures, and over generations to better understand the multiple ways in which the epigenome may respond to environmental stimuli.
authors.affiliation: University of Southern California, Los Angeles, California, USA.
authors.forename: Carrie V
authors.initials: CV
authors.lastname: Breton
authors.forename: Carmen J
authors.initials: CJ
authors.lastname: Marsit
authors.forename: Elaine
authors.initials: E
authors.lastname: Faustman
authors.forename: Kari
authors.initials: K
authors.lastname: Nadeau
authors.forename: Jaclyn M
authors.initials: JM
authors.lastname: Goodrich
authors.forename: Dana C
authors.initials: DC
authors.lastname: Dolinoy
authors.forename: Julie
authors.initials: J
authors.lastname: Herbstman
authors.forename: Nina
authors.initials: N
authors.lastname: Holland
authors.forename: Janine M
authors.initials: JM
authors.lastname: LaSalle
authors.forename: Rebecca
authors.initials: R
authors.lastname: Schmidt
authors.forename: Paul
authors.initials: P
authors.lastname: Yousefi
authors.forename: Frederica
authors.initials: F
authors.lastname: Perera
authors.forename: Bonnie R
authors.initials: BR
authors.lastname: Joubert
authors.forename: Joseph
authors.initials: J
authors.lastname: Wiemels
authors.forename: Michele
authors.initials: M
authors.lastname: Taylor
authors.forename: Ivana V
authors.initials: IV
authors.lastname: Yang
authors.forename: Rui
authors.initials: R
authors.lastname: Chen
authors.forename: Kinjal M
authors.initials: KM
authors.lastname: Hew
authors.forename: Deborah M Hussey
authors.initials: DM
authors.lastname: Freeland
authors.forename: Rachel
authors.initials: R
authors.lastname: Miller
authors.forename: Susan K
authors.initials: SK
authors.lastname: Murphy
mesh_terms: D002648:Child; D000067576:Child Health; D002669:Child Welfare; D019175:DNA Methylation; D004781:Environmental Exposure; D004782:Environmental Health; D044127:Epigenesis, Genetic; D057890:Epigenomics; D005260:Female; D006126:Group Processes; D006801:Humans; D008137:Longitudinal Studies; D011247:Pregnancy; D012106:Research