Impact of statin therapy on plasma vitamin D levels: A systematic review and meta-analysis

Background: During recent years, treatment with statins has been suggested to induce several effect on bone status and vitamin D metabolism, interpreted as statins pleiotropic effects. Actually, the available data are not conclusive and the characteristics of this association remains unclear. Aim: The purpose of this meta-analysis was therefore to investigate the possible effect of statins therapy on vitamin D serum levels based on the reported results from RCTs and observational studies. Methods: PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases were searched to identify studies evaluating the impact of statins on plasma vitamin D concentrations from inception to September 16, 2015. A systematic assessment of bias in the included randomized controlled trials was performed using the Cochrane criteria. A random-effects model (using DerSimonian-Laird method) and the generic inverse variance method were used for the heterogeneity of studies in terms of demographic characteristics of populations being studied and also differences in study design and type of statin being studied. Sensitivity analysis was conducted using the leave-one-out method. Results: Following a multiple database search, 1422 published studies were identified; among these, 7 studies were found to be eligible and included in the systematic review and meta-analysis. Our meta-analysis of data from seven studies (including 5 RCTs) did not indicate any significant effect of statins treatment on plasma vitamin D levels. Conclusion: Further well-designed trials are necessary to confirm these results and to define better a possible relationship between statins and vitamin D levels.