Cancer risk among statin users: A population‐based cohort study

Abstract Hydroxymethylglutaryl‐CoA reductase inhibitors (statins) have been linked with potential chemopreventive effects; however, the data are conflicting. We conducted a population‐based cohort study using data from the Prescription Database of North Jutland County and the Danish Cancer Registry for the period 1989–2002. In a study population of 334,754 county residents, we compared overall and site‐specific cancer incidence among 12,251 statin users (≥2 prescriptions) with cancer incidence among nonusers and users of other lipid‐lowering drugs ( n = 1,257). Statistical analyses were based on age‐standardization and Poisson regression analysis, adjusting for age, gender, calendar period and use of NSAIDs, hormone replacement therapy and cardiovascular drugs. We identified 398 cancer cases among statin users during a mean follow‐up period of 3.3 years (range 0–14 years). The age‐ and gender‐standardized incidence rates of cancer overall were 596 per 100,000 person‐years among statin users, 645 per 100,000 person‐years among nonusers and 795 per 100,000 person‐years among users of other lipid‐lowering drugs. Adjusted rate ratios for cancer overall among statin users were 0.86 (95% CI, 0.78–0.95) compared to nonusers and 0.73 (95% CI, 0.55–0.98) compared to users of other lipid‐lowering drugs. No significantly increased or decreased rate ratios were observed for any of the studied site‐specific cancers (liver, colorectum, lung, breast, prostate, female genital organs and lymphatic and haematopoietic tissue), but most estimates tended to be less than 1.0. Stratification by duration of follow‐up or number of prescriptions revealed no clear trends. In summary, individuals prescribed statins experienced a slightly reduced cancer incidence compared to population controls of nonusers and users of other lipid‐lowering drugs. Larger and longer‐term studies are needed to determine the potentially protective effect of statin use on cancer development. © 2004 Wiley‐Liss, Inc.