Table 1.
Distribution of Baseline Demographic and Health-Related Characteristics by Treatment Arm, Analysis Population (n=1,683)a
| Placebo Arm | Selenium Arm | Vitamin E Arm | ||||
|---|---|---|---|---|---|---|
|
|
||||||
| Characteristic | Cohortb
(n = 481) N (%) |
High- Gradec (n = 78) N (%) |
Cohortb
(n = 476) N (%) |
High-Gradec
(n = 97) N (%) |
Cohortb
(n = 477) N (%) |
High-Gradec
(n = 103) N (%) |
| Age, years | ||||||
| Median (IQR) | 63 (59,68) | 65 (60,69) | 63 (59,69) | 64 (60,69) | 63 (59,68) | 65 (61,69) |
| <60 | 126 (26.2%) | 19 (24.4%) | 131 (27.5%) | 22 (22.7%) | 120 (25.2%) | 14 (13.6%) |
| 60-64 | 150 (31.2%) | 20 (25.6%) | 135 (28.4%) | 29 (29.9%) | 146 (30.6%) | 33 (32.0%) |
| 65-69 | 116 (24.1%) | 22 (28.2%) | 121 (25.4%) | 26 (26.8%) | 131 (27.5%) | 33 (32.0%) |
| ≥70 | 89 (18.5%) | 17 (21.8%) | 89 (18.7%) | 20 (20.6%) | 80 (16.8%) | 23 (22.3%) |
| Family history of prostate cancer |
||||||
| No | 406 (84.4%) | 56 (71.8%) | 403 (84.7%) | 71 (73.2%) | 396 (83.0%) | 78 (75.7%) |
| Yes | 74 (15.4%) | 22 (28.2%) | 73 (15.3%) | 26 (26.8%) | 81 (17.0%) | 25 (24.3%) |
| Unknown | 1 (0.2%) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) |
| Body mass index, kg/m2 |
||||||
| Median (IQR) | 28.1 (25.6,31.4) |
28.5 (26.1,30.5) |
27.7 (25.6,30.8) |
28 (25.5,31.1) |
28.1 (25.8,31) |
27.8 (25.2,31.7) |
| <25 | 93 (19.3%) | 14 (17.9%) | 89 (18.7%) | 18 (18.6%) | 83 (17.4%) | 24 (23.3%) |
| 25-<30 | 223 (46.4%) | 40 (51.3%) | 243 (51.1%) | 47 (48.5%) | 243 (50.9%) | 46 (44.7%) |
| ≥30 | 164 (34.1%) | 24 (30.8%) | 143 (30.0%) | 31 (32.0%) | 150 (31.4%) | 33 (32.0%) |
| Unknown | 1 (0.2%) | 0 (0.0%) | 1 (0.2%) | 1 (1.0%) | 1 (0.2%) | 0 (0.0%) |
| Diabetes | ||||||
| No | 441 (91.7%) | 73 (93.6%) | 437 (91.8%) | 88 (90.7%) | 430 (90.1%) | 95 (92.2%) |
| Yes | 40 (8.3%) | 5 (6.4%) | 39 (8.2%) | 9 (9.3%) | 47 (9.9%) | 8 (7.8%) |
| Prostate Specific Antigen (ng/mL)d |
||||||
| Median (IQR) | 1.1 (0.7,1.8) | 2.2 (1.5,3.1) | 1.2 (0.7,2) | 2.5 (1.8,3.2) | 1.1 (0.6,1.9) | 2.4 (1.7,3.1) |
| <1.0 | 211 (43.9%) | 6 (7.7%) | 184 (38.7%) | 7 (7.2%) | 200 (41.9%) | 9 (8.7%) |
| 1.01-1.99 | 165 (34.3%) | 24 (30.8%) | 166 (34.9%) | 26 (26.8%) | 161 (33.8%) | 27 (26.2%) |
| 2.00-2.99 | 61 (12.7%) | 25 (32.1%) | 77 (16.2%) | 30 (30.9%) | 75 (15.7%) | 37 (35.9%) |
| 3.00-3.99 | 44 (9.1%) | 23 (29.5%) | 49 (10.3%) | 34 (35.1%) | 40 (8.4%) | 30 (29.1%) |
| ≥4.00 | 0 (0%) | 0 (0%) | 0 (0%) | 0 (0%) | 1 (0%) | 0 (0%) |
| Smoking Status | ||||||
| Never | 201 (41.8%) | 34 (43.6%) | 206 (43.3%) | 48 (49.5%) | 200 (41.9%) | 50 (48.5%) |
| Former | 252 (52.4%) | 39 (50.0%) | 241 (50.6%) | 45 (46.4%) | 256 (53.7%) | 49 (47.6%) |
| Current | 25 (5.2%) | 3 (3.8%) | 29 (6.1%) | 4 (4.1%) | 20 (4.2%) | 4 (3.9%) |
| Unknown | 3 (0.6%) | 2 (2.6%) | 0 (0.0%) | 0 (0.0%) | 1 (0.2%) | 0 (0.0%) |
| Highest level of education completed |
||||||
| High school or less |
96 (20.0%) | 10 (12.8%) | 91 (19.1%) | 22 (22.7%) | 81 (17.0%) | 23 (22.3%) |
| Some college or vocational school |
113 (23.5%) | 20 (25.6%) | 135 (28.4%) | 23 (23.7%) | 129 (27.0%) | 22 (21.4%) |
| College graduate or higher |
268 (55.7%) | 46 (59.0%) | 249 (52.3%) | 52 (53.6%) | 266 (55.8%) | 58 (56.3%) |
| Unknown | 4 (0.8%) | 2 (2.6%) | 1 (0.2%) | 0 (0.0%) | 1 (0.2%) | 0 (0.0%) |
| Marital status | ||||||
| Currently married/ cohabitating |
421 (87.5%) | 66 (84.6%) | 391 (82.1%) | 82 (84.5%) | 414 (86.8%) | 86 (83.5%) |
| Previously married |
45 (9.4%) | 7 (9.0%) | 62 (13.0%) | 13 (13.4%) | 46 (9.6%) | 15 (14.6%) |
| Never married | 12 (2.5%) | 3 (3.8%) | 21 (4.4%) | 2 (2.1%) | 15 (3.1%) | 2 (1.9%) |
| Unknown | 3 (0.6%) | 2 (2.6%) | 2 (0.4%) | 0 (0.0%) | 2 (0.4%) | 0 (0.0%) |
| % of annual PSA tests done |
||||||
| <25% | 47 (9.8%) | 2 (2.6%) | 46 (9.7%) | 3 (3.1%) | 36 (7.5%) | 2 (1.9%) |
| 25-<50% | 47 (9.8%) | 7 (9.0%) | 54 (11.3%) | 5 (5.2%) | 56 (11.7%) | 5 (4.9%) |
| 50-<75% | 185 (38.5%) | 30 (38.5%) | 167 (35.1%) | 35 (36.1%) | 182 (38.2%) | 38 (36.9%) |
| 75-<100% | 154 (32.0%) | 28 (35.9%) | 155 (32.6%) | 23 (23.7%) | 164 (34.4%) | 25 (24.3%) |
| 100% | 48 (10.0%) | 11 (14.1%) | 54 (11.3%) | 31 (32.0%) | 39 (8.2%) | 33 (32.0%) |
| Supplemental Vitamin E (IU/dy) |
||||||
| Median (IQR) | 15 (10,20) | 15 (11,20) | 15 (10,22) | 16 (11,23) | 15 (10,23) | 15 (11,22) |
| <25 | 400 (83.2%) | 64 (82.1%) | 390 (81.9%) | 77 (79.4%) | 379 (79.5%) | 85 (82.5%) |
| 25-<50 | 68 (14.1%) | 12 (15.4%) | 74 (15.5%) | 19 (19.6%) | 89 (18.7%) | 15 (14.6%) |
| 50-<75 | 11 (2.3%) | 2 (2.6%) | 9 (1.9%) | 1 (1.0%) | 8 (1.7%) | 3 (2.9%) |
| 75-<100 | 0 (0.0%) | 0 (0.0%) | 3 (0.6%) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) |
| ≥100 | 2 (0.4%) | 0 (0.0%) | 0 (0.0%) | 0 (0.0%) | 1 (0.2%) | 0 (0.0%) |
| Supplemental Selenium (μg/dy) |
||||||
| Median (IQR) | 134 (101,172) | 136 (97,183) | 131 (94,174) | 148 (113,189) |
133 (98,170) | 132 (96,175) |
| 0 | 2 (0.4%) | 2 (2.6%) | 1 (0.2%) | 0 (0.0%) | 1 (0.2%) | 0 (0.0%) |
| <50 | 14 (2.9%) | 1 (1.3%) | 17 (3.6%) | 1 (1.0%) | 9 (1.9%) | 1 (1.0%) |
| 50-<100 | 103 (21.4%) | 18 (23.1%) | 119 (25.0%) | 16 (16.5%) | 116 (24.3%) | 28 (27.2%) |
| 100-<150 | 170 (35.3%) | 27 (34.6%) | 159 (33.4%) | 35 (36.1%) | 175 (36.7%) | 34 (33.0%) |
| ≥150 | 192 (39.9%) | 30 (38.5%) | 180 (37.8%) | 45 (46.4%) | 176 (36.9%) | 40 (38.8%) |
a
Analysis population was taken from the pre-existing SELECT case-cohort, restricted to Caucasian only, and to the Placebo, Selenium, and Vitamin E treatment arms only.
b
The cohort includes high-grade cases as follows: Placebo arm, 9; Selenium Arm, 14; Vitamin E arm, 6.
c
High-grade cases are those with Gleason scores available for the diagnostic biopsy, with Gleason score 7 or higher.
d
One patient in the cohort had a baseline PSA of 10.6, although the study eligibility criteria required PSA <= 4.00. This participant was retained in analyses.
IQR: inter-quartile range; PSA: Prostate Specific Antigen