Table 1.

Distribution of baseline demographic and health-related characteristics by treatment arm, analysis population (n = 1,683)a

Placebo armSelenium armVitamin E arm
CohortbHigh-gradecCohortbHigh-gradecCohortbHigh-gradec
(n = 481)(n = 78)(n = 476)(n = 97)(n = 477)(n = 103)
CharacteristicN (%)N (%)N (%)N (%)N (%)N (%)
Age, years
 Median (IQR)63 (59,68)65 (60,69)63 (59,69)64 (60,69)63 (59,68)65 (61,69)
 <60126 (26.2%)19 (24.4%)131 (27.5%)22 (22.7%)120 (25.2%)14 (13.6%)
 60–64150 (31.2%)20 (25.6%)135 (28.4%)29 (29.9%)146 (30.6%)33 (32.0%)
 65–69116 (24.1%)22 (28.2%)121 (25.4%)26 (26.8%)131 (27.5%)33 (32.0%)
 ≥7089 (18.5%)17 (21.8%)89 (18.7%)20 (20.6%)80 (16.8%)23 (22.3%)
Family history of prostate cancer
 No406 (84.4%)56 (71.8%)403 (84.7%)71 (73.2%)396 (83.0%)78 (75.7%)
 Yes74 (15.4%)22 (28.2%)73 (15.3%)26 (26.8%)81 (17.0%)25 (24.3%)
 Unknown1 (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)
 <2593 (19.3%)14 (17.9%)89 (18.7%)18 (18.6%)83 (17.4%)24 (23.3%)
 25–<30223 (46.4%)40 (51.3%)243 (51.1%)47 (48.5%)243 (50.9%)46 (44.7%)
 ≥30164 (34.1%)24 (30.8%)143 (30.0%)31 (32.0%)150 (31.4%)33 (32.0%)
 Unknown1 (0.2%)0 (0.0%)1 (0.2%)1 (1.0%)1 (0.2%)0 (0.0%)
Diabetes
 No441 (91.7%)73 (93.6%)437 (91.8%)88 (90.7%)430 (90.1%)95 (92.2%)
 Yes40 (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)
 <1.0211 (43.9%)6 (7.7%)184 (38.7%)7 (7.2%)200 (41.9%)9 (8.7%)
 1.01–1.99165 (34.3%)24 (30.8%)166 (34.9%)26 (26.8%)161 (33.8%)27 (26.2%)
 2.00–2.9961 (12.7%)25 (32.1%)77 (16.2%)30 (30.9%)75 (15.7%)37 (35.9%)
 3.00–3.9944 (9.1%)23 (29.5%)49 (10.3%)34 (35.1%)40 (8.4%)30 (29.1%)
 ≥4.000 (0%)0 (0%)0 (0%)0 (0%)1 (0%)0 (0%)
Smoking status
 Never201 (41.8%)34 (43.6%)206 (43.3%)48 (49.5%)200 (41.9%)50 (48.5%)
 Former252 (52.4%)39 (50.0%)241 (50.6%)45 (46.4%)256 (53.7%)49 (47.6%)
 Current25 (5.2%)3 (3.8%)29 (6.1%)4 (4.1%)20 (4.2%)4 (3.9%)
 Unknown3 (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 less96 (20.0%)10 (12.8%)91 (19.1%)22 (22.7%)81 (17.0%)23 (22.3%)
 Some college or vocational school113 (23.5%)20 (25.6%)135 (28.4%)23 (23.7%)129 (27.0%)22 (21.4%)
 College graduate or higher268 (55.7%)46 (59.0%)249 (52.3%)52 (53.6%)266 (55.8%)58 (56.3%)
 Unknown4 (0.8%)2 (2.6%)1 (0.2%)0 (0.0%)1 (0.2%)0 (0.0%)
Marital status
 Currently married/cohabitating421 (87.5%)66 (84.6%)391 (82.1%)82 (84.5%)414 (86.8%)86 (83.5%)
 Previously married45 (9.4%)7 (9.0%)62 (13.0%)13 (13.4%)46 (9.6%)15 (14.6%)
 Never married12 (2.5%)3 (3.8%)21 (4.4%)2 (2.1%)15 (3.1%)2 (1.9%)
 Unknown3 (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/day)
 Median (IQR)15 (10,20)15 (11,20)15 (10,22)16 (11,23)15 (10,23)15 (11,22)
 <25400 (83.2%)64 (82.1%)390 (81.9%)77 (79.4%)379 (79.5%)85 (82.5%)
 25–<5068 (14.1%)12 (15.4%)74 (15.5%)19 (19.6%)89 (18.7%)15 (14.6%)
 50–<7511 (2.3%)2 (2.6%)9 (1.9%)1 (1.0%)8 (1.7%)3 (2.9%)
 75–<1000 (0.0%)0 (0.0%)3 (0.6%)0 (0.0%)0 (0.0%)0 (0.0%)
 ≥1002 (0.4%)0 (0.0%)0 (0.0%)0 (0.0%)1 (0.2%)0 (0.0%)
Supplemental selenium (μg/day)
 Median (IQR)134 (101,172)136 (97,183)131 (94,174)148 (113,189)133 (98,170)132 (96,175)
 02 (0.4%)2 (2.6%)1 (0.2%)0 (0.0%)1 (0.2%)0 (0.0%)
 <5014 (2.9%)1 (1.3%)17 (3.6%)1 (1.0%)9 (1.9%)1 (1.0%)
 50–<100103 (21.4%)18 (23.1%)119 (25.0%)16 (16.5%)116 (24.3%)28 (27.2%)
 100–<150170 (35.3%)27 (34.6%)159 (33.4%)35 (36.1%)175 (36.7%)34 (33.0%)
 ≥150192 (39.9%)30 (38.5%)180 (37.8%)45 (46.4%)176 (36.9%)40 (38.8%)
  • Abbreviations: IQR, interquartile range; PSA, prostate-specific antigen.

  • aAnalysis 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.

  • bThe cohort includes high-grade cases as follows: placebo arm, 9; selenium arm, 14; vitamin E arm, 6.

  • cHigh-grade cases are those with Gleason scores available for the diagnostic biopsy, with Gleason score 7 or higher.

  • dOne 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.