Low-dose aspirin or other nonsteroidal anti-inflammatory drug use and prostate cancer risk: a nationwide study.

Abstract

Increasing evidence suggests that aspirin use may protect against prostate cancer. In a nationwide case-control study, using Danish high-quality registry data, we evaluated the association between the use of low-dose aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs) and the risk of prostate cancer. We identified 35,600 patients (cases) with histologically verified prostate cancer during 2000-2012. Cases were matched to 177,992 population controls on age and residence by risk-set sampling. Aspirin and nonaspirin NSAID exposure was defined by type, estimated dose, duration, and consistency of use. We used conditional logistic regression to estimate odds ratios (ORs), with 95% confidence intervals (CIs), for prostate cancer associated with low-dose aspirin (75-150mg) or nonaspirin NSAID use, adjusted for potential confounders. Use of low-dose aspirin was associated with an OR for prostate cancer of 0.94 (95% CI 0.91-0.97). Slightly lower ORs were seen with increasing cumulative amount, duration, and consistency of low-dose aspirin use (continuous use, ≥5years: OR 0.89; 95% CI 0.82-0.97; ≥10years: OR 0.86; 95% CI 0.70-1.06). Nonaspirin NSAID use was associated with a slightly increased OR for prostate cancer (1.13; 95% CI 1.10-1.15); however, this association was confined to localized disease and did not vary materially with amount, duration, or consistency of nonaspirin NSAID use. Our study indicates that long-term, consistent low-dose aspirin use may provide modest protection against prostate cancer. The slightly increased risk of only localized prostate cancer with nonaspirin NSAID use suggests a noncausal explanation of the observed association.