Table 2

Frequency distribution of established risk factors for prostate cancer among cases and controls

SubgroupNumber of cases (n = 483)Number of controls (n = 548)P
Age (years)
 ≤5010 (2.1%)22 (4.0%)
 51–60106 (21.9%)136 (24.8%)
 61–70195 (40.4%)267 (48.7%)
 >70172 (35.6%)123 (22.5%)0.0001
Prostate-specific antigen (ng/ml)
 ≤4.018 (3.7%)76 (13.9%)
 4.1–10.0261 (54.1%)303 (55.3%)
 10.1–20.0143 (29.6%)139 (25.4%)
 >20.061 (12.6%)30 (5.5%)0.0001
Digital rectal exam
 Nonpalpable238 (49.3%)343 (62.6%)
 Assymetry115 (23.8%)116 (21.2%)
 Nodule130 (26.9%)89 (16.2%)0.0001
Ethnic background
 Caucasian421 (87.2%)444 (81.0%)
 Black45 (9.3%)45 (8.2%)
 Asian12 (2.5%)47 (8.6%)0.0001
 Other5 (1.0%)12 (2.2%)
Family history of prostate cancer
 Negative417 (86.3%)487 (88.9%)
 Positive66 (13.7%)61 (11.1%)0.22
Obstructive urinary symptoms
 Absent112 (23.2%)107 (19.5%)
 Present371 (76.8%)441 (80.5%)0.15