DNA methylation signatures of breastfeeding in buccal cells collected in mid-childhood

Veronika V. Odintsova*, Fiona A. Hagenbeek, Matthew Suderman, Doretta Caramaschi, Catharina E.M. van Beijsterveldt, Noah A. Kallsen, Erik A. Ehli, Gareth E. Davies, Gennady T. Sukhikh, Vassilios Fanos, Caroline Relton, Meike Bartels, Dorret I. Boomsma, Jenny van Dongen

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

Breastfeeding has long-term benefits for children that may be mediated via the epigenome. This pathway has been hypothesized, but the number of empirical studies in humans is small and mostly done by using peripheral blood as the DNA source. We performed an epigenome-wide association study (EWAS) in buccal cells collected around age nine (mean = 9.5) from 1006 twins recruited by the Netherlands Twin Register (NTR). An age-stratified analysis examined if effects attenuate with age (median split at 10 years; n<10 = 517, mean age = 7.9; n>10 = 489, mean age = 11.2). We performed replication analyses in two independent cohorts from the NTR (buccal cells) and the Avon Longitudinal Study of Parents and Children (ALSPAC) (peripheral blood), and we tested loci previously associated with breastfeeding in epigenetic studies. Genome-wide DNA methylation was assessed with the Illumina Infinium MethylationEPIC BeadChip (Illumina, San Diego, CA, USA) in the NTR and with the HumanMethylation450 Bead Chip in the ALSPAC. The duration of breastfeeding was dichotomized ('never' vs. 'ever'). In the total sample, no robustly associated epigenome-wide significant CpGs were identified (α = 6.34 × 10-8). In the sub-group of children younger than 10 years, four significant CpGs were associated with breastfeeding after adjusting for child and maternal characteristics. In children older than 10 years, methylation differences at these CpGs were smaller and non-significant. The findings did not replicate in the NTR sample (n = 98; mean age = 7.5 years), and no nearby sites were associated with breastfeeding in the ALSPAC study (n = 938; mean age = 7.4). Of the CpG sites previously reported in the literature, three were associated with breastfeeding in children younger than 10 years, thus showing that these CpGs are associated with breastfeeding in buccal and blood cells. Our study is the first to show that breastfeeding is associated with epigenetic variation in buccal cells in children. Further studies are needed to investigate if methylation differences at these loci are caused by breastfeeding or by other unmeasured confounders, as well as what mechanism drives changes in associations with age.

Original languageEnglish
Article number2804
Pages (from-to)1-26
Number of pages26
JournalNutrients
Volume11
Issue number11
DOIs
Publication statusPublished - 17 Nov 2019

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Keywords

  • ALSPAC
  • Breastfeeding
  • DNA methylation
  • EPIC
  • EWAS
  • NTR
  • Twins

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