Table 2

ORs and 95% CIs for the association of vasectomy with risk of prostate cancer, King County, Washington, 1993–1996

Vasectomy statusNo. (%) of casesNo. (%) of controlsORa95% CI
Ever
 No456 (60.6)438 (62.3)1.00b
 Yes297 (39.4)265 (37.7)1.100.9 –1.4
Age at vasectomy
 20–29 yrs49 (6.5)47 (6.7)1.150.7 –1.8
 30–34 yrs84 (11.2)66 (9.4)1.300.9 –1.9
 35–39 yrs82 (10.9)74 (10.5)1.070.7 –1.6
 ≥40 yrs82 (10.9)77 (11.0)0.960.7 –1.4
Trend testdP = 0.24
Years since vasectomyc
 <58 (1.1)10 (1.4)0.680.2 –1.9
  5–914 (1.9)21 (3.0)0.680.3 –1.5
 10–1430 (4.0)35 (5.0)0.940.5 –1.6
 15–1963 (8.4)58 (8.3)1.110.7 –1.7
 20–2481 (10.8)64 (9.1)1.110.8 –1.6
 25–2963 (8.4)46 (6.5)1.420.9 –2.2
 ≥3038 (5.0)30 (4.3)1.230.7 –2.1
Trend testdP = 0.11
Year of vasectomy
 1952–196881 (10.8)61 (8.7)1.370.9 –2.0
 1969–1974100 (13.1)80 (11.4)1.160.8 –1.7
 1975–197962 (8.2)61 (8.7)1.010.7 –1.5
 1980–198434 (4.5)31 (4.4)1.140.7 –1.9
 1985–19898 (1.1)21 (3.0)0.380.1 –0.9
 1990–199512 (1.6)10 (1.4)1.000.4 –2.6
Trend testdP = 0.09
  • a Adjusted for age (continuous), race, family history of prostate cancer (none, first-degree relative, second-degree relative only), and number of PSA blood tests within 5 years before the reference date (0, 1–2, 3–4, ≥5).

  • b Reference group for all ORs related to vasectomy.

  • c Analysis excludes one control with missing information.

  • d Trend test based on exposed subjects only.