Table 1.

Age-adjusted baseline characteristics of subjects by vasectomy status and trial arm

Control armScreening arm
No vasectomyVasectomyNo vasectomyVasectomy
N (%)26,249 (72.4%)9,987 (27.6%)27,276 (73.0%)10,083 (27.0%)
Age, mean (SD)a,b63.3 (5.4)61.5 (4.8)63.1 (5.4)61.5 (4.8)
Age at vasectomy, n (%)
 <25155 (1.6%)136 (1.4%)
 25–343,201 (32.2%)3,244 (32.3%)
 35–445,084 (51.1%)5,124 (51.1%)
 45+1,501 (15.1%)1,527 (15.2%)
Body mass index (kg/m2), mean (SD)27.6 (2.6)27.5 (4.2)27.6 (2.5)27.6 (4.2)
Smoking pack years, median (IQR)a,b13.9 (0.0–41.6)14.6 (0.0–43.3)13.1 (0.0–40.6)16.7 (0.0–42.6)
Prostate cancer family history, n (%)
 No24,306 (92.6%)9,278 (92.9%)25,230 (92.5%)9,337 (92.6%)
 Yes1,943 (7.4%)709 (7.1%)2,046 (7.5%)746 (7.4%)
Black, n (%)a,b1,549 (5.9%)110 (1.1%)1,609 (5.9%)91 (0.9%)
Hispanic, n (%)b656 (2.5%)220 (2.2%)682 (2.5%)192 (1.9%)
Aspirin use, n (%)a,b13,387 (51%)5,433 (54.4%)14,129 (51.8%)5,263 (52.2%)
Hypertension, n (%)a,b9,292 (35.4%)3,246 (32.5%)9,356 (34.3%)3,317 (32.9%)
Diabetes, n (%)a,b2,441 (9.3%)767 (7.7%)2,564 (9.4%)766 (7.6%)
PSA test in last 3 years prior to study entry, n (%)a,b
 No13,361 (50.9%)4,484 (44.9%)14,184 (52%)4,729 (46.9%)
 Yes12,888 (49.1%)5,503 (55.1%)13,092 (48.0%)5,354 (53.1%)
Digital rectal exam in 3 years prior to study entry, n (%)a,b
 No15,014 (42.8%)3,745 (37.5%)11,756 (43.1%)3,922 (38.9%)
 Yes11,235 (57.2%)6,242 (62.5%)15,520 (56.9%)6,161 (61.1%)
  • NOTE: P values generated using age-adjusted linear models, generalized linear models, and quantile regressions to compare means or medians of baseline covariates.

  • aP < 0.05 between no vasectomy and vasectomy groups in the control arm of the trial.

  • bP < 0.05 between no vasectomy and vasectomy groups in the screening arm of the trial.