title: Breastfeeding, breast milk and viruses.
abstract: BACKGROUND
  There is seemingly consistent and compelling evidence that there is no association between breastfeeding and breast cancer. An assumption follows that milk borne viruses cannot be associated with human breast cancer. We challenge this evidence because past breastfeeding studies did not determine "exposure" of newborn infants to colostrum and breast milk.
  
  
  METHODS
  We conducted a prospective review of 100 consecutive births of infants in the same centre to determine the proportion of newborn infants who were "exposed" to colostrum or breast milk, as distinct from being fully breast fed. We also report a review of the breastfeeding practices of mothers of over 87,000 newborn infants in the Australian State of New South Wales. This study was approved by the Human Research Ethics Committee of the University of New South Wales (Sydney, Australia). Approval 05063, 29 September 2005.
  
  
  RESULTS
  Virtually all (97 of 100) newborn infants in this centre were "exposed" to colostrum or breast milk whether or not they were fully breast fed. Between 82.2% to 98.7% of 87,000 newborn infants were "exposed" to colostrum or breast milk.
  
  
  CONCLUSIONS
  In some Western communities there is near universal exposure of new born infants to colostrum and breast milk. Accordingly it is possible for the transmission of human milk borne viruses. This is contrary to the widespread assumption that human milk borne viruses cannot be associated with breast cancer.
authors.affiliation: School of Public Health and Community Medicine, University of New South Wales, Sydney, Australia. james.lawson@unsw.edu.au
authors.forename: James S
authors.initials: JS
authors.lastname: Lawson
authors.forename: Joy
authors.initials: J
authors.lastname: Heads
authors.forename: Wendy K
authors.initials: WK
authors.lastname: Glenn
authors.forename: Noel J
authors.initials: NJ
authors.lastname: Whitaker
mesh_terms: D001942:Breast Feeding; D001943:Breast Neoplasms / Q000209:etiology / Q000821:virology*; D016009:Chi-Square Distribution; D003126:Colostrum / Q000821:virology*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical; D008895:Milk, Human / Q000821:virology*; D009517:New South Wales; D011446:Prospective Studies; D012307:Risk Factors