title: The 25(OH)D/PTH threshold in black women.
abstract: BACKGROUND
  Black women have lower 25-hydroxyvitamin D [25(OH)D] and higher PTH than white women. Recent evidence implicates PTH in adverse cardiovascular outcomes.
  
  
  OBJECTIVE
  The objective of the study was to determine whether PTH increases at lower 25(OH)D levels (the threshold) in black compared with white women.
  
  
  METHODS
  Healthy black and white women, aged 20-80 yr were recruited to participate in a cross-sectional study of body-composition in black and white women. Measurement of serum 25(OH)D and PTH were carried out.
  
  
  METHODS
  The study was a convenience sample recruited from a community setting.
  
  
  METHODS
  Healthy black and white women were recruited by advertising and a direct mail campaign in a comparative study of body composition. Age ranged from 20-to 80 yr. There were 148 black and 129 white premenopausal participants and 87 black and 139 white postmenopausal participants.
  
  
  RESULTS
  The main outcome was to determine whether the threshold for 25(OH)D/PTH differs in black and white women.
  
  
  RESULTS
  A threshold of 37 nmol/liter (95% confidence interval 35-40) was found for black and 59 nmol/liter (95% confidence interval 56-63) for white women. These two values were significantly different (P < 0.001).
  
  
  CONCLUSIONS
  Black women have an increase in serum PTH at a lower 25(OH)D level than white women. Negative health outcomes of higher PTH should be investigated in black women.
authors.affiliation: Bone Mineral Research Center, Winthrop-University Hospital, Mineola, New York 11501, USA. jaloia@winthrop.org
authors.forename: John F
authors.initials: JF
authors.lastname: Aloia
authors.forename: Ding-Geng
authors.initials: DG
authors.lastname: Chen
authors.forename: Henian
authors.initials: H
authors.lastname: Chen
mesh_terms: D000328:Adult; D001741:Black or African American; D000368:Aged; D000369:Aged, 80 and over; D001823:Body Composition; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007118:Immunoassay; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D044465:White People
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D