Use of statins and risk of myeloproliferative neoplasms - a Danish nationwide case-control study.

Previous studies have indicated a possible cancer protective effect of statins in solid cancers; however, this has never been investigated for myeloproliferative neoplasms (MPNs). We aimed to investigate the association between statin use and risk of MPNs in a nested nationwide case-control study, using Danish national population registries. Information on statin use was ascertained, using the Danish National Prescription Registry and patients diagnosed with MPNs between 2010-2018 were identified using The Danish National Chronic Myeloid Neoplasia Registry. The association between statin use and MPNs was estimated using age- and sex adjusted odds ratios (ORs) and fully adjusted odds ratios (aORs), adjusting for prespecified confounders. The study population included 3,816 cases with MPNs and 19,080 population controls (5:1) matched on age and sex by incidence density sampling. Overall, 34.9% of cases and 33.5% of controls were ever-users of statins, resulting in a OR for MPN of 1.07 (95% CI: 0.99-1.16) and an aOR of 0.87 (95% CI: 0.80-0.96), respectively. Among cases, 17.2% were categorized as long-term users (≥5 years) compared to 19.0% among controls, yielding an OR for MPN of 0.90 (95% CI: 0.81-1.00) and an aOR of 0.72 (95% CI: 0.64-0.81). Analyzing the effect of cumulative duration of statin use revealed a dose-dependent response and the association was consistent in sex, age, MPN subgroups and across different statin types. Statin use was associated with a significantly lower odds of being diagnosed with an MPN, indicating a possible cancer-preventive effect of statins. The prospective design of our study precludes causal inference.