Statin Use and Chronic Lymphocytic Leukemia Incidence: A Nested Case-Control Study in Manitoba, Canada

Recent studies have reported reduced risk of chronic lymphocytic leukemia (CLL) among statin users. However, the possibility that the effect of statins may differ by their chemical or pharmacodynamic properties has not been investigated. In this nested case-control study, all Manitobans ages ≥40 years when diagnosed with CLL (as a first cancer) from 1999 to 2014 ( = 1,385) were matched (on gender, age, residence, and duration of insurance coverage) to cancer-free controls ( = 6,841). Using conditional logistic regression, statin use was analyzed by individual statins and groups: hydrophilic, low-potency lipophilic (fluvastatin and lovastatin), and high-potency lipophilic statins. Statin users constituted 27% and 28% of the CLL cases and controls, respectively. After adjusting for potential confounding by indication, patterns of healthcare utilization, and use of other drugs, CLL incidence was not associated with use of hydrophilic [odds ratio (OR) = 1.08; 95% confidence interval (CI), 0.86-1.34] or high-potency lipophilic (OR = 0.94; 95% CI, 0.79-1.11) statins. Low-potency lipophilic statins were associated with a lower risk of CLL (OR = 0.64; 95% CI, 0.45-0.92), with stronger association (OR = 0.44; 95% CI, 0.22-0.88) observed with more regular use (half to full standard dose on average). We found an association between low-potency lipophilic statin use and reduced CLL risk, with a possible dose-response effect. Although requiring replication in future studies, our findings suggest that the effect of statins on CLL risk may depend on their specific chemical or pharmacodynamic properties.