Table 1

Distribution of potential confounding factors (%) among control men without and with vasectomy, King County, Washington, 1993–1996

FactorControls without vasectomy (n = 438)Controls with vasectomy (n = 265)
Age at reference date (yrs)
 40–498.47.9
 50–5418.321.9
 55–5935.640.8
 60–6437.729.4
Race
 Caucasian96.499.2
 African-American3.60.8
Family history of prostate cancer
 None85.283.4
 First-degree relative8.412.1
 Second-degree relative6.44.5
Marital status
 Married77.687.5
 Single5.70
 Other16.712.5
Annual income ($)
 <30,00015.78.3
 30,000–49,99925.621.9
 50,000–74,99923.333.2
 75,000–99,99916.717.4
 ≥100,00017.617.7
 Unknown1.11.5
Education
 High school or less23.023.8
 Some college19.428.3
 College graduate28.824.9
 Graduate/professional school28.823.0
Ever visited a urologist33.138.5
History of BPHa10.315.1
Current smokerb16.015.5
Regular consumer of alcoholic beveragesc86.190.6
Religious preference
 Protestant/other60.365.7
 Catholic17.612.5
 Jewish2.30.8
 None19.921.1
Hospitalized within the past year
 No85.686.8
 Yes14.413.2
No. of physical exams within past 5 years
  012.610.9
 1–236.537.7
 3–419.220.8
 ≥531.730.6
No. of DREs within past 5 years
  014.616.6
 1–241.137.0
 3–425.620.7
 ≥523.725.7
No. of PSAs within past 5 years
  066.467.9
 1–220.816.2
 3–47.89.4
 ≥55.06.4
  • a BPH diagnosed by a physician >2 years before reference date.

  • b Current smoker is defined as smoking at reference date.

  • c Regular consumer is defined as ≥ monthly drinking of alcoholic beverages for ≥6 months.