title: Western environment/lifestyle is associated with increased genome methylation and decreased gene expression in Chinese immigrants living in Australia.
abstract: BACKGROUND
  Several human diseases and conditions are disproportionally distributed in the world with a significant "Western-developed" vs. "Eastern-developing" gradient.
  
  
  METHODS
  We compared genome-wide DNA methylation of peripheral blood mononuclear cells in 25 newly arrived Chinese immigrants living in a Western environment for less than 6 months ("Newly arrived") with 23 Chinese immigrants living in the Western environment for more than two years ("Long-term") with a mean of 8.7 years, using the Infinium HumanMethylation450 BeadChip. In a sub-group of both subject groups (n = 12 each) we also investigated genome-wide gene expression using a Human HT-12 v4 expression beadChip.
  
  
  RESULTS
  There were 62.5% probes among the total number of 382,250 valid CpG sites with greater mean Beta (β) in "Long-term" than in "Newly arrived". In the regions of CpG islands and gene promoters, compared with the CpG sites in all other regions, lower percentages of CpG sites with mean methylation levels in "Long-term" greater than "Newly arrived" were observed, but still >50%. The increase of methylation was associated with a general decrease of gene expression in Chinese immigrants living in the Western environment for a longer period of time. After adjusting for age, gender and other confounding factors the findings remained.
  
  
  CONCLUSIONS
  Chinese immigrants living in Australia for a longer period of time have increased overall genome methylation and decreased overall gene expression compared with newly arrived immigrants.
authors.affiliation: School of Public Health, Curtin University, Perth, Australia.|School of Paediatrics and Child Health, The University of Western Australia, Perth, Australia.
authors.forename: Guicheng
authors.initials: G
authors.lastname: Zhang
authors.affiliation: School of Medicine, Shihezhi University, Xinjiang, China.|Biostatistical Analysis Pty Ltd, Australia.|The University of Queensland, Brisbane, Australia.
authors.forename: Kui
authors.initials: K
authors.lastname: Wang
authors.affiliation: School of Paediatrics and Child Health, The University of Western Australia, Perth, Australia.
authors.forename: Ennee
authors.initials: E
authors.lastname: Schultz
authors.affiliation: School of Paediatrics and Child Health, The University of Western Australia, Perth, Australia.
authors.forename: Siew-Kim
authors.initials: SK
authors.lastname: Khoo
authors.affiliation: School of Paediatrics and Child Health, The University of Western Australia, Perth, Australia.|Thoracic Surgery Department, Hebei General Hospital, Shijiazhuang, People's Republic of China.
authors.forename: Xiaopeng
authors.initials: X
authors.lastname: Zhang
authors.affiliation: School of Paediatrics and Child Health, The University of Western Australia, Perth, Australia.
authors.forename: Alicia
authors.initials: A
authors.lastname: Annamalay
authors.affiliation: School of Paediatrics and Child Health, The University of Western Australia, Perth, Australia.|Telethon Kids Institute, The University of Western Australia, Perth, Australia.
authors.forename: Ingrid A
authors.initials: IA
authors.lastname: Laing
authors.affiliation: Telethon Kids Institute, The University of Western Australia, Perth, Australia.
authors.forename: Belinda J
authors.initials: BJ
authors.lastname: Hales
authors.affiliation: School of Paediatrics and Child Health, The University of Western Australia, Perth, Australia.
authors.forename: Jack
authors.initials: J
authors.lastname: Goldblatt
authors.affiliation: School of Paediatrics and Child Health, The University of Western Australia, Perth, Australia.
authors.forename: Peter N
authors.initials: PN
authors.lastname: Le Souëf
mesh_terms: D000328:Adult; D044466:Asian People / Q000235:genetics*; D001315:Australia; D018899:CpG Islands; D019175:DNA Methylation; D054242:Emigrants and Immigrants; D004777:Environment; D057890:Epigenomics / Q000379:methods; D015870:Gene Expression; D059647:Gene-Environment Interaction; D015894:Genome, Human; D006801:Humans; D007963:Leukocytes, Mononuclear; D008019:Life Style; D012307:Risk Factors
keywords: developed countries; developing countries; gene expression; methylation