Effects of long-term alpha-tocopherol supplementation on serum hormones in older men.
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.
Hartman
T J
TJ
Department of Nutrition, Pennsylvania State University, University Park, Pennsylvania, USA.
Dorgan
J F
JF
Woodson
K
K
Virtamo
J
J
Tangrea
J A
JA
Heinonen
O P
OP
Taylor
P R
PR
Barrett
M J
MJ
Albanes
D
D
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*
D012738:Sex Hormone-Binding Globulin; D014810:Vitamin E; D013739:Testosterone; D000735:Androstenedione; D003687:Dehydroepiandrosterone; D011388:Prolactin; D002784:Cholesterol