A large cohort study of long-term acetaminophen use and prostate cancer incidence

Use of aspirin and other nonsteroidal anti-inflammatory drugs (NSAID), particularly long-term use, has been associated with modestly reduced risk of prostate cancer in previous epidemiologic studies. Acetaminophen, a commonly used pain reliever, is not traditionally considered an NSAID but can have anti-inflammatory effects. Few studies have examined the association between long-term acetaminophen use and prostate cancer incidence.

We examined the association between acetaminophen use and prostate cancer incidence among 78,485 men in the Cancer Prevention Study II Nutrition Cohort. Information on acetaminophen use was obtained from a questionnaire completed at study enrollment in 1992 and updated by using follow-up questionnaires in 1997 and every two years thereafter. Relative risks (RR) were estimated by using proportional hazards regression models. All models were adjusted for age, race, education, body mass index, diabetes, NSAID use, and history of prostate-specific antigen testing.

During follow-up from 1992 through 2007, 8,092 incident prostate cancer cases were identified. Current regular use of acetaminophen (30 or more pills per month) for 5 or more years was associated with lower risk of overall prostate cancer (RR = 0.62, 95% CI: 0.44-0.87) and aggressive prostate cancer (RR = 0.49, 95% CI: 0.27-0.88). Current regular use of less than 5 years duration was not associated with prostate cancer risk.

These results suggest that long-term regular acetaminophen use may be associated with lower prostate cancer risk.

If the association between acetaminophen use and lower risk of prostate cancer is confirmed, it could provide clues about biological mechanisms that are important in prostate carcinogenesis.