title: Racial variation in umbilical cord blood sex steroid hormones and the insulin-like growth factor axis in African-American and white female neonates.
abstract: OBJECTIVE
  To evaluate whether there is racial variation in venous umbilical cord blood concentrations of sex steroid hormones and the insulin-like growth factor (IGF) axis between female African-American and white neonates.
  
  
  METHODS
  Maternal and birth characteristics and venous umbilical cord blood samples were collected from 77 African-American and 41 white full-term uncomplicated births at two urban hospitals in 2004 and 2005. Cord blood was measured for testosterone, dehydroespiandrosterone-sulfate, estradiol, and sex steroid hormone-binding globulin (SHBG) by immunoassay. IGF-1, IGF-2, and IGF-binding protein-3 (IGFBP-3) were measured by ELISA. Crude and multivariable-adjusted geometric mean concentrations were computed for the hormones.
  
  
  RESULTS
  African-American neonates weighed less at birth (3,228 g vs. 3,424 g, p < 0.004) than whites. Birth weight was positively correlated with IGF-1, IGFBP-3, and the molar ratio of IGF-1 to IGFBP-3, but inversely correlated with the molar ratio of IGF-2 to IGFBP-3. Adjusted models showed higher testosterone (1.82 ng/ml vs. 1.47 ng/ml, p = 0.006) and the molar ratio of testosterone to SHBG (0.42 vs. 0.30, p = 0.03) in African-American compared to white female neonates. IGF-1, IGF-2, and IGFBP-3 were lower in African-American compared to white female neonates, but only the difference for IGF-2 remained significant (496.5 ng/ml vs. 539.2 ng/ml, p = 0.04).
  
  
  CONCLUSIONS
  We provide evidence of racial variation in cord blood testosterone and testosterone to SHBG in African-American compared to white female neonates, and higher IGF-2 in white compared to African-American female neonates. Findings suggest plausible explanations for a prenatal influence on subsequent breast cancer risk and mortality. Further work is needed to confirm these observations.
authors.affiliation: Division of Cancer Control and Population Sciences, National Cancer Institute, Bethesda, MD, USA. collinsta@mail.nih.gov
authors.forename: Tanya
authors.initials: T
authors.lastname: Agurs-Collins
authors.forename: Sabine
authors.initials: S
authors.lastname: Rohrmann
authors.forename: Catherine
authors.initials: C
authors.lastname: Sutcliffe
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Bienstock
authors.forename: Deborah
authors.initials: D
authors.lastname: Monsegue
authors.forename: Folasade
authors.initials: F
authors.lastname: Akereyeni
authors.forename: Gary
authors.initials: G
authors.lastname: Bradwin
authors.forename: Nader
authors.initials: N
authors.lastname: Rifai
authors.forename: Michael N
authors.initials: MN
authors.lastname: Pollak
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Platz
mesh_terms: D001741:Black or African American; D004797:Enzyme-Linked Immunosorbent Assay; D004958:Estradiol / Q000097:blood; D005260:Female; D005312:Fetal Blood / Q000378:metabolism*; D012739:Gonadal Steroid Hormones / Q000097:blood*; D006801:Humans; D007231:Infant, Newborn; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D007335:Insulin-Like Growth Factor II / Q000378:metabolism*; D015999:Multivariate Analysis; D010865:Pilot Projects; D012737:Sex Factors; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism; D018709:Statistics, Nonparametric; D013739:Testosterone / Q000097:blood; D014481:United States; D044465:White People
chemical_list: D012739:Gonadal Steroid Hormones; D018972:Insulin-Like Growth Factor Binding Protein 3; D012738:Sex Hormone-Binding Globulin; D013739:Testosterone; D004958:Estradiol; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II