Cimetidine use and the risk for prostate cancer: results from the VITAL cohort study

The histamine-2 (H(2)) blocker cimetidine may alter androgen, zinc, and prolactin levels, which could alter prostate cancer risk. Increased risk for men filling more than 20 cimetidine prescriptions was reported previously. We examined the association between cimetidine use and prostate cancer risk in a cohort in western Washington State.

Participants were 33,506 men, 50 to 76 years old, enrolled in the VITamins And Lifestyle cohort (VITAL). H(2)-blocker use during the prior 10 years was self-reported through baseline questionnaire between October 2000 and December 2002. Men were followed up for subsequent prostate cancer by linkage to the Surveillance, Epidemiology and End Results cancer registry. We identified 548 incident invasive prostate cancer cases diagnosed from baseline to December 31, 2003.

Overall, no association between ever use of cimetidine or years of cimetidine use and prostate cancer risk was observed. However, daily cimetidine use for 10 years was associated with increased risk (relative risk, 2.35; 95% confidence interval, 1.05-5.26) compared with nonuse of any H(2) blockers. Use of other H(2) blockers was not associated with prostate cancer.

Additional studies are needed to determine whether long-term daily cimetidine use is associated with increased prostate cancer risk in other populations, and if so, the reason for this association.