title: Effects of long-term alpha-tocopherol supplementation on serum hormones in older men.
abstract: BACKGROUND
  alpha-tocopherol supplementation significantly reduced risk of prostate cancer in the Alpha-Tocopherol Beta-Carotene Cancer Prevention (ATBC) Study. Sex hormones are thought to be involved in the etiology of prostate cancer. We examined whether long-term supplementation with alpha-tocopherol modified serum hormone levels.
  
  
  METHODS
  Men who were cancer-free consumed > or = 90% of the study capsules, and who had both baseline and follow-up blood available, were eligible for the study. One hundred men who received alpha-tocopherol were matched on age, study center, and length of time between blood draws to 100 men who received a placebo. Multivariate linear regression models which allowed for a separate intercept for each matched pair were used to evaluate the effect of alpha-tocopherol supplementation on follow-up hormone concentrations.
  
  
  RESULTS
  Compared to men who received a placebo, we found significantly lower serum androstenedione (P = 0.04) and testosterone (P = 0.04) concentrations among men who received alpha-tocopherol, after controlling for baseline hormone level, follow-up serum cholesterol concentration, body mass index, smoking, and fasting time. Geometric mean (95% confidence interval; CI) androstenedione concentration among men who received alpha-tocopherol was 145 ng/dl (CI, 137-153) after adjusting for covariates, compared to 158 ng/dl (CI, 148-167) among men who received a placebo. Mean testosterone concentrations for men who received alpha-tocopherol and placebo were 539 (CI, 517-562) and 573 (CI, 549-598) ng/dl, respectively.
  
  
  CONCLUSIONS
  These results suggest that long-term alpha-tocopherol supplementation decreases serum androgen concentrations, and could have been one of the factors contributing to the observed reduction in incidence and mortality of prostate cancer in the alpha-tocopherol treatment group of the ATBC Study.
authors.affiliation: Department of Nutrition, Pennsylvania State University, University Park, Pennsylvania, USA.
authors.forename: T J
authors.initials: TJ
authors.lastname: Hartman
authors.forename: J F
authors.initials: JF
authors.lastname: Dorgan
authors.forename: K
authors.initials: K
authors.lastname: Woodson
authors.forename: J
authors.initials: J
authors.lastname: Virtamo
authors.forename: J A
authors.initials: JA
authors.lastname: Tangrea
authors.forename: O P
authors.initials: OP
authors.lastname: Heinonen
authors.forename: P R
authors.initials: PR
authors.lastname: Taylor
authors.forename: M J
authors.initials: MJ
authors.lastname: Barrett
authors.forename: D
authors.initials: D
authors.lastname: Albanes
mesh_terms: D000428:Alcohol Drinking; D000735:Androstenedione / Q000097:blood*; D002784:Cholesterol / Q000097:blood; D003687:Dehydroepiandrosterone / Q000097:blood; D004435:Eating; D005500:Follow-Up Studies; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011388:Prolactin / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood* / Q000517:prevention & control; D011863:Radioimmunoassay; D012044:Regression Analysis; D012738:Sex Hormone-Binding Globulin / Q000032:analysis; D012907:Smoking; D013739:Testosterone / Q000097:blood*; D014810:Vitamin E / Q000008:administration & dosage*
chemical_list: D012738:Sex Hormone-Binding Globulin; D014810:Vitamin E; D013739:Testosterone; D000735:Androstenedione; D003687:Dehydroepiandrosterone; D011388:Prolactin; D002784:Cholesterol