title: A twin study of breastfeeding with a preliminary genome-wide association scan.
abstract: Breastfeeding has been an important survival trait during human history, though it has long been recognized that individuals differ in their exact breastfeeding behavior. Here our aims were, first, to explore to what extent genetic and environmental influences contributed to the individual differences in breastfeeding behavior; second, to detect possible genetic variants related to breastfeeding; and lastly, to test if the genetic variants associated with breastfeeding have been previously found to be related with breast size. Data were collected from a large community-based cohort of Australian twins, with 3,364 women participating in the twin modelling analyses and 1,521 of them included in the genome-wide association study (GWAS). Monozygotic (MZ) twin correlations (r MZ = 0.52, 95% CI 0.46-0.57) were larger than dizygotic (DZ) twin correlations (r DZ = 0.35, 95% CI 0.25-0.43) and the best-fitting model was the one composed by additive genetics and unique environmental factors, explaining 53% and 47% of the variance in breastfeeding behavior, respectively. No breastfeeding-related genetic variants reached genome-wide significance. The polygenic risk score analyses showed no significant results, suggesting breast size does not influence breastfeeding. This study confers a replication of a previous one exploring the sources of variance of breastfeeding and, to our knowledge, is the first one to conduct a GWAS on breastfeeding and look at the overlap with variants for breast size.
authors.affiliation: QIMR Berghofer Medical Research Institute,Brisbane,Queensland,Australia.
authors.forename: Lucia
authors.initials: L
authors.lastname: Colodro-Conde
authors.affiliation: QIMR Berghofer Medical Research Institute,Brisbane,Queensland,Australia.
authors.forename: Gu
authors.initials: G
authors.lastname: Zhu
authors.affiliation: MRC Social Genetic & Developmental Psychiatry Centre,Institute of Psychiatry,King's College London,DeCrespigny Park,Denmark Hill,London,UK.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Power
authors.affiliation: QIMR Berghofer Medical Research Institute,Brisbane,Queensland,Australia.
authors.forename: Anjali
authors.initials: A
authors.lastname: Henders
authors.affiliation: School of Psychiatry,Washington University School of Medicine,St. Louis,MO,USA.
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Heath
authors.affiliation: School of Psychiatry,Washington University School of Medicine,St. Louis,MO,USA.
authors.forename: Pamela A F
authors.initials: PA
authors.lastname: Madden
authors.affiliation: QIMR Berghofer Medical Research Institute,Brisbane,Queensland,Australia.
authors.forename: Grant W
authors.initials: GW
authors.lastname: Montgomery
authors.affiliation: QIMR Berghofer Medical Research Institute,Brisbane,Queensland,Australia.
authors.forename: Sarah
authors.initials: S
authors.lastname: Medland
authors.affiliation: Murcia Twin Registry,Department of Human Anatomy and Psychobiology,University of Murcia,IMIB-Arrixaca,Murcia,Spain.
authors.forename: Juan R
authors.initials: JR
authors.lastname: Ordoñana
authors.affiliation: QIMR Berghofer Medical Research Institute,Brisbane,Queensland,Australia.
authors.forename: Nicholas G
authors.initials: NG
authors.lastname: Martin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001315:Australia; D001942:Breast Feeding / Q000706:statistics & numerical data / Q000639:trends; D002877:Chromosomes, Human / Q000235:genetics; D015331:Cohort Studies; D005260:Female; D055106:Genome-Wide Association Study; D060005:Genotyping Techniques; D006801:Humans; D008297:Male; D008875:Middle Aged; D020411:Oligonucleotide Array Sequence Analysis; D020641:Polymorphism, Single Nucleotide; D017584:Reproductive History; D012189:Retrospective Studies; D057566:Self Report; D011795:Surveys and Questionnaires; D014429:Twins, Dizygotic / Q000235:genetics* / Q000523:psychology / Q000706:statistics & numerical data; D014430:Twins, Monozygotic / Q000235:genetics* / Q000523:psychology / Q000706:statistics & numerical data
keywords: genome-wide association study