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 in myeloproliferative neoplasms (MPNs). We aimed to investigate the association between statin use and the risk of MPNs in a nested nationwide case-control study, using Danish national population registries. Information on statin use was obtained from the Danish National Prescription Registry, and patients diagnosed with MPNs between 2010 and 2018 were identified from 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 ORs (aORs), adjusting for prespecified confounders. The study population included 3816 cases with MPNs and 19 080 population controls (5:1) matched for age and sex using incidence density sampling. Overall, 34.9% of the cases and 33.5% of the controls ever used statins, resulting in an OR for MPN of 1.07 (95% confidence interval [CI], 0.99-1.16) and an aOR of 0.87 (95% CI, 0.80-0.96), respectively. 17.2% were categorized as long-term users (≥5 years) among the cases compared with 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). Analysis of the effect of the cumulative duration of statin use revealed a dose-dependent response, and the association was consistent for sex, age, and MPN subgroups and across different statin types. Statin users were associated with significantly lower odds of being diagnosed with an MPN, indicating a possible cancer-preventive effect of statins. The retrospective design of this study precludes causal inferences.