title: Racial variation in vitamin D cord blood concentration in white and black male neonates.
abstract: OBJECTIVE
  The aim of this study is to evaluate racial variation in umbilical cord blood concentration of vitamin D and to explore its correlation with markers of the insulin-like growth factor axis (IGFs) and sex steroid hormones in white and black male neonates.
  
  
  METHODS
  In 2004-2005, venous umbilical cord blood samples were collected from 75 black and 38 white male neonates, along with maternal and birth characteristics from two hospitals in Maryland, United States. 25-Hydroxyvitamin D [25(OH)D] and 1,25-dihydroxyvitamin D [1,25(OH)(2)D] were measured by radioimmunoassay and testosterone, estradiol, and sex hormone-binding globulin (SHBG) by immunoassay and IGF-1, IGF-2, and IGF-binding protein-3 by ELISA. Crude and multivariable-adjusted geometric mean concentrations were computed.
  
  
  RESULTS
  Mean 25(OH)D levels were lower in black than in white neonates (11.44; 95 % CI 10.10-12.95 ng/mL vs. 18.24; 95 % CI 15.32-21.72 ng/mL; p < 0.0001). Black neonates were at higher risk of suboptimal vitamin D levels [25(OH)D < 20 ng/mL] than whites (84 vs. 63 %). 25(OH)D concentrations varied by season in whites but not in blacks and were significantly inversely correlated with mother's parity (number of live births) in blacks but not in whites. Mean concentration of 1,25(OH)(2)D did not differ by race. 25(OH)D and 1,25(OH)(2)D did not correlate with IGFs, sex steroid hormones, and SHBG.
  
  
  CONCLUSIONS
  Suboptimal vitamin D levels were prevalent especially in blacks and influenced by mother's parity and by season. The observed vitamin D differences between black and white neonates warrant further evaluation of the etiology of the disparity in chronic diseases in adulthood.
authors.affiliation: Division of Cancer Epidemiology and Prevention, Institute of Social and Preventive Medicine, University of Zurich, Hirschengraben 84, Zürich, Switzerland. monika.eichholzer@ifspm.uzh.ch
authors.forename: Monika
authors.initials: M
authors.lastname: Eichholzer
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Platz
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: Bruce W
authors.initials: BW
authors.lastname: Hollis
authors.forename: Ronald
authors.initials: R
authors.lastname: Horst
authors.forename: Nader
authors.initials: N
authors.lastname: Rifai
authors.forename: Michael N
authors.initials: MN
authors.lastname: Pollak
authors.forename: Aline
authors.initials: A
authors.lastname: Barbir
authors.forename: Tanya
authors.initials: T
authors.lastname: Agurs-Collins
authors.forename: Sabine
authors.initials: S
authors.lastname: Rohrmann
mesh_terms: D000328:Adult; D044383:Black People / Q000706:statistics & numerical data; D005260:Female; D005312:Fetal Blood / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D007231:Infant, Newborn / Q000097:blood* / Q000378:metabolism; D008297:Male; D008396:Maryland / Q000453:epidemiology; D009994:Osmolar Concentration; D011247:Pregnancy; D044469:Racial Groups / Q000706:statistics & numerical data; D014481:United States / Q000453:epidemiology; D014807:Vitamin D / Q000032:analysis / Q000097:blood* / Q000378:metabolism; D044465:White People / Q000706:statistics & numerical data; D055815:Young Adult; D001741:Black or African American
chemical_list: D014807:Vitamin D