Table 1.
Characteristics of the participants and comparison across quintile of total testosterone level at baseline, 632 prostate cancer-free men with initial-PSA < 4 ng/mL
| Quintile of testosterone level at baseline (ng/dL) | ||||||
|---|---|---|---|---|---|---|
| Overall | 20.0 to < 193.0 | 193.0 to < 265.0 | 265.0 to < 342.5 | 342.5to < 477.0 | 477.0–1500.0 | |
| N | 632 | 128 | 123 | 130 | 131 | 120 |
| Age, years | ||||||
| Mean (SD) | 59.3 (10.5) | 60.1 (11.9) | 59.1 (9.0) | 59.1 (11.0) | 58.6 (10.0) | 59.7 (10.6) |
| Race, % | ||||||
| White | 75.0 | 71.1 | 78.1 | 73.9 | 74.1 | 78.3 |
| Black | 10.3 | 9.4 | 8.9 | 10.0 | 13.0 | 10.0 |
| Other | 1.7 | 1.6 | 2.4 | 2.3 | 0.8 | 1.7 |
| Unknown | 13.0 | 18.0 | 10.6 | 13.9 | 12.2 | 10.0 |
| Smoking status, % | ||||||
| Current smoker | 5.7 | 10.9 | 3.3 | 2.3 | 4.6 | 7.5 |
| Former smoker | 40.4 | 35.2 | 39.0 | 44.6 | 39.7 | 43.3 |
| Never smoke | 34.8 | 28.9 | 39.8 | 34.6 | 40.5 | 30.0 |
| Unknown | 19.2 | 25.0 | 17.9 | 18.5 | 15.3 | 17.2 |
| Body mass index, % | ||||||
| < 25 | 47.3 | 43.9 | 44.1 | 44.6 | 51.5 | 52.5* |
| 25 to < 30 | 16.0 | 19.5 | 11.4 | 17.7 | 17.6 | 13.3 |
| ≥ 30 | 18.8 | 30.5 | 23.6 | 14.6 | 11.5 | 14.2 |
| Unknown | 17.9 | 6.1 | 21.0 | 23.1 | 19.5 | 20.0 |
| Family history of prostate cancer, % | 3.2 | 3.1 | 3.2 | 3.1 | 2.7 | 3.9 |
| Diabetes, % | 13.1 | 27.5 | 17.2 | 8.8 | 6.8 | 5.1* |
| No. of testosterone measurements | ||||||
| Mean (SD) | 4.3 (3.5) | 5.2 (3.9) | 4.9 (4.1) | 4.4 (3.8) | 3.7 (2.7) | 3.4 (2.1)*† |
| Time interval between first and most recent testosterone measurement, months | ||||||
| Mean (SD) | 61.4 (50.1) | 47.9 (46.8) | 54.8 (50.3) | 61.6 (62.0) | 76.7 (50.1) | 65.8 (46.7)*† |
| No. of PSA measurements | ||||||
| Mean (SD) | 4.8 (3.5) | 4.0 (2.9) | 4.8 (3.8) | 4.7 (4.0) | 5.4 (3.3) | 5.1 (3.4)*† |
| Time interval between first and most recent PSA measurement, months | ||||||
| Mean (SD) | 57.5 (48.5) | 43.2 (42.1) | 54.0 (49.8) | 54.9 (50.3) | 70.1 (46.9) | 65.1 (49.1)*† |
| Time interval between baseline and first PSA measurement, months | ||||||
| Mean (SD) | 12.3 (23.1) | 14.5 (27.4) | 9.2 (15.9) | 9.5 (17.2) | 15.9 (28.4) | 12.0 (22.9) |
PSA, prostate-specific antigen; SD, standard deviation
*Test for differences among quintiles of testosterone level at baseline from Wald chi-square test for proportions or one-way ANOVA for means, P < 0.05
†Ptrend was calculated by modeling continuous covariates and median value of baseline testosterone by quintile and Ptrend < 0.05