title: Association of serum sex steroid hormone hemodilution and body mass index among healthy postmenopausal women.
abstract: OBJECTIVE
  Hemodilution refers to reduced concentrations of analytes in the blood secondary to increased fluid volume. Given that obesity is associated with expanded vascular volume, hemodilution may result in a lower ratio of blood concentrations of analytes among heavier subjects. Assessing the relationship of hormone concentration to total mass varies by body mass index (BMI) is etiologically important because obesity is related to hormone metabolism and cancer risk.
  
  
  METHODS
  We evaluated data for 194 postmenopausal controls in an endometrial cancer case-control study. Height, weight, and serum hormone concentrations were measured previously. We estimated serum hormone mass from concentration based on estimates of calculated plasma volume. We assessed the effect of BMI on relationships of sex steroid hormone concentration and mass using multivariate linear regression.
  
  
  RESULTS
  Higher BMI was associated with increased estrone, estrone sulfate, estradiol, and albumin-bound estradiol concentrations and masses (p-trend ≤ 0.001). With increasing BMI, androstenedione concentration did not change significantly (p-trend = 0.548), but its mass increased (p-trend = 0.024).
  
  
  CONCLUSIONS
  Relationships of sex steroid hormone concentration and mass were generally similar, except for androstenedione in which the relationship was only significant for mass. Future studies to assess both sex steroid hormone concentration and mass may have value in etiological research.
authors: Hormonal and Reproductive Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
authors: Hannah P
authors: HP
authors: Yang
authors: Amanda
authors: A
authors: Black
authors: Roni T
authors: RT
authors: Falk
authors: Louise A
authors: LA
authors: Brinton
authors: Nancy
authors: N
authors: Potischman
authors: Nicolas
authors: N
authors: Wentzensen
authors: Jessica M
authors: JM
authors: Faupel-Badger
authors: Mark E
authors: ME
authors: Sherman
mesh_terms: D000368:Aged; D000886:Anthropometry; D015992:Body Mass Index; D005260:Female; D012739:Gonadal Steroid Hormones / Q000097:blood*; D006438:Hemodilution; D006801:Humans; D016014:Linear Models; D008875:Middle Aged; D009765:Obesity; D017698:Postmenopause / Q000502:physiology*; D014481:United States
chemical_list: D012739:Gonadal Steroid Hormones