Table 1.

Mean plasma sex steroid hormone concentrations and androgen receptor gene CAG repeat length in prostate cancer cases and matched controls nested in the Health Professionals Follow-up Study, 1993-1998

Prostate cancer casesControlsP*P
n448448
    Testosterone (ng/mL)4.83 ± 1.754.83 ± 1.680.970.95
    Free testosterone (pg/mL)27.6 ± 8.327.4 ± 8.00.78
    Dihydrotestosterone (pg/mL)424 ± 255424 ± 2390.990.97
    Androstanediol glucuronide (ng/mL)5.05 ± 3.144.99 ± 3.390.78
    Estradiol (pg/mL)28.9 ± 8.828.8 ± 8.30.700.74
    SHBG (nmol/L)98.3 ± 45.998.7 ± 46.30.90
n460460
    Androgen receptor gene CAG repeat length22.0 ± 3.221.8 ± 3.00.48
  • * For the hypothesis test of no difference in means (paired t test) between prostate cancer cases and controls. All tests are two sided.

  • For the hypothesis test of no difference in means between prostate cancer cases and controls after adjusting, the sex steroid hormones for SHBG by linear regression. Mutual adjustment was done because the concentrations of some sex steroid hormones and SHBG are moderately correlated (testosterone: Pearson r = 0.71, estradiol: r = −0.32, and dihydrotestosterone: r = 0.32; all P < 0.0001).