Vasectomy has been reported to be associated with an increased risk of
prostate cancer in western countries. A hospital-based case-control s
tudy was conducted in 12 cities in China to evaluate the relationship
between vasectomy and prostate cancer risk in China, a low-risk countr
y with rising incidence and increasing use of vasectomy. Interviews we
re conducted with 138 histologically confirmed prostate cancer cases d
iagnosed during 1989-1992 and 638 controls (158 hospital cancer, 158 h
ospital noncancer, and 322 neighborhood controls) of similar ages. Vas
ectomy at least 10 years prior to interview was reported by 10% of the
cases versus 3% of the controls. Odds ratios for prostate cancer asso
ciated with vasectomy were 2.0 (95% confidence interval, 0.7-6.1), 3.3
(95% confidence interval, 1.0-11.3), and 6.7 (95% confidence interval
, 2.1-21.6), respectively, when hospital cancer, hospital noncancer, a
nd neighborhood controls were used for comparison. Although detection
bias is of concern, the data suggest that in China, men with a history
of vasectomy may experience an increased risk of prostate cancer.