Statin use and risk of prostate cancer: Results from the Southern Community Cohort Study

Abstract

Background Epidemiologic studies suggest that statin use may be inversely associated with risk of prostate cancer, but prior studies have focused predominantly on non-Hispanic white populations. Methods We evaluated the association between statin use and prostate cancer risk in the Southern Community Cohort Study (SCCS). Study participants were 32,091 men aged 40-79 at baseline, 67% of whom were non-Hispanic black. Between study enrollment (2002-2009) and December 31, 2010, 570 prostate cancer cases were diagnosed, including 324 low-grade cancers (Gleason score <7 or Gleason pattern 3+4) and 107 high-grade cancers (Gleason score >7 or Gleason pattern 4+3). Analyses of overall prostate cancer were conducted using Cox regression and analyses of grade-specific cancer were conducted using competing risks models. Results Ten percent of non-Hispanic black men and 22% of non-Hispanic white men reported use of statins at study enrollment. As compared to non-use, statin use was associated with a non-significant 14% lower risk of prostate cancer in multivariable models (Hazard Ratio [HR]:0.86; 95% Confidence Interval [CI]:0.63-1.18). This association was stronger for high-grade cancer (HR: 0.62; 95% CI: 0.30, 1.28) than low-grade cancer (HR:0.98; 95% CI:0.65-1.48). Results were similar by race/ethnicity (p-interaction:0.41) and did not vary by history of prostate-specific antigen [PSA] screening (p-interaction:0.65). Conclusions Results suggest no strong association between statin use and prostate cancer risk overall, and further suggest that if a modest protective effect does exist, it does not vary by race/ethnicity and may be restricted to high-grade tumors, although power to detect differences by subgroup was limited.

Statin Use and Prostate Cancer Aggressiveness: Results from the Population-Based North Carolina–Louisiana Prostate Cancer Project

“…We observed a similar magnitude of association between statin use and prostate cancer aggressiveness in both CAs and AAs; findings were supported by a prior study, which found that associations between statin use and risk of high-grade prostate cancer did not vary by race (16). In contrast to prior cohort and case-control analyses of statin use and prostate cancer risk using prostate cancer-free men as the referent group (5, 8, 16), the case-only design of this study examined the impact of statin use on disease aggressiveness among men diagnosed with prostate cancer.…”

The current evidence on statin use and prostate cancer prevention: are we there yet?

“…A retrospective cohort study in Israel of 37,645 men taking statins found a 74% reduced risk of total prostate cancer in long-term statin users, defined as >5 years of statin use, in comparison with nonusers 74 . Other studies found weaker but still inverse associations between statin use and total prostate cancer risk 75,76 , including a population-based study in Washington, USA, that found that statin users had a nonsignificant 12% lower prostate cancer risk 17 .…”

“…Six large, prospective studies all found that statin users had a reduced risk of advanced prostate cancer without any reduction, or with an attenuated reduction, in total prostate cancer risk 8,9,11,76,80,82 . In all six studies, bias was minimized by controlling for potential confounding variables, for example, concomitant diseases, such as diabetes, use of antidiabetic drugs or other treatments and cardiovascular risk factors that are associated with prostate cancer risk, such as age, race and body mass index.…”

“…Investigators of another prospective cohort, using data from the Cancer Prevention Study II Nutrition Survey ( n = 55,454) 9 , found that men who took statins for ≥5 years had a 40% reduced risk of advanced prostate cancer but these findings were only just statistically significant (RR 0.60; 95% CI 0.36–1.00) and did not reach significance in a follow-up analysis of this data-set 80 . Analyses of data from the California Men’s Health Study ( n = 69,047) 11 , Southern Community Cohort Study ( n = 32,091) 76 and Kaiser Permanente Medical Care Program ( n = 2,097,474) 82 found 20%, 38% and 17% reductions, respectively, in the risk of advanced prostate cancer among statin users; however, only the findings from Kaiser Permanente, the largest of these studies, were statistically significant (HR 0.83; 95% CI 0.72–0.96).…”

“…Overall, these relationships might explain the reduced risk of advanced prostate cancer observed in statin users. However, a number of studies reported that adjusting for the intensity of PSA screening did not affect the association between statin use and risk of advanced disease 76,98,99 . The most recent meta-analysis, published in 2012, reported that the findings of studies which controlled statistical models for potential confounding introduced by differing rates of PSA screening between statin users and nonusers did not greatly differ from the findings of studies that did not consider differences in PSA screening 83 In addition, PSA testing is performed much more rarely in Europe compared with the USA, which makes the case-control studies set in Denmark 18 and Finland 10 relatively free from this potential bias 100 .…”