title: Association of serum α-tocopherol with sex steroid hormones and interactions with smoking: implications for prostate cancer risk.
abstract: BACKGROUND
  Vitamin E may protect against prostate cancer, possibly only in smokers and, we hypothesize, through altered sex steroid hormones. A controlled trial in smokers showed that sex hormone levels were inversely associated with baseline serum α-tocopherol and decreased in response to vitamin E supplementation. The vitamin E-hormone relation is understudied in non-smokers.
  
  
  METHODS
  Serum sex steroid hormones and α-tocopherol were measured for 1,457 men in NHANES III. Multivariable-adjusted geometric mean hormone concentrations by α-tocopherol quintile were estimated.
  
  
  RESULTS
  We observed lower mean testosterone, estradiol, and SHBG concentrations with increasing serum α-tocopherol (Q1 = 5.5 and Q5 = 4.6 ng/ml, p-trend = 0.0007; Q1 = 37.8 and Q5 = 33.1 pg/ml, p-trend = 0.02; Q1 = 38.8 and Q5 = 30.6 pg/ml, p-trend = 0.05, respectively). Interactions between serum α-tocopherol and exposure to cigarette smoke for total testosterone, total estradiol, and SHBG were found with the inverse relation observed only among smokers.
  
  
  CONCLUSIONS
  Results from this nationally representative, cross-sectional study indicate an inverse association between serum α-tocopherol and circulating testosterone, estradiol, and SHBG, but only in men who smoked. Our findings support vitamin E selectively influencing sex hormones in smokers and afford possible mechanisms through which vitamin E may impact prostate cancer risk.
authors.affiliation: Nutritional Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Department of Health and Human Services, Bethesda, MD, USA. mondulam@mail.nih.gov
authors.forename: Alison M
authors.initials: AM
authors.lastname: Mondul
authors.forename: Sabine
authors.initials: S
authors.lastname: Rohrmann
authors.forename: Andy
authors.initials: A
authors.lastname: Menke
authors.forename: Manning
authors.initials: M
authors.lastname: Feinleib
authors.forename: William G
authors.initials: WG
authors.lastname: Nelson
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Platz
authors.forename: Demetrius
authors.initials: D
authors.lastname: Albanes
mesh_terms: D000328:Adult; D002277:Carcinoma / Q000097:blood / Q000453:epidemiology / Q000208:ethnology / Q000209:etiology*; D003430:Cross-Sectional Studies; D012739:Gonadal Steroid Hormones / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D011471:Prostatic Neoplasms / Q000097:blood / Q000453:epidemiology / Q000208:ethnology / Q000209:etiology*; D012307:Risk Factors; D012738:Sex Hormone-Binding Globulin / Q000032:analysis; D012907:Smoking / Q000009:adverse effects / Q000097:blood* / Q000453:epidemiology; D013739:Testosterone / Q000097:blood; D055815:Young Adult; D024502:alpha-Tocopherol / Q000097:blood*
chemical_list: D012739:Gonadal Steroid Hormones; D012738:Sex Hormone-Binding Globulin; D013739:Testosterone; D024502:alpha-Tocopherol