title: Statin therapy and plasma vitamin E concentrations: A systematic review and meta-analysis of randomized placebo-controlled trials.
abstract: BACKGROUND
  Vitamin E is one of the most important natural antioxidants, and its plasma levels are inversely associated with the progression of atherosclerosis. There have been reports suggesting a potential negative effect of statin therapy on plasma vitamin E levels. The aim of this meta-analysis was to determine the impact of statin therapy on plasma vitamin E concentrations.
  
  
  METHODS
  PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases were searched to identify randomized placebo-controlled trials evaluating the impact of statins on plasma vitamin E concentrations from inception to February 27, 2015. A systematic assessment of bias in the included studies was performed using the Cochrane criteria. A random-effects model (using DerSimonian-Laird method) and the generic inverse variance method were used to examine the effect of statins on plasma vitamin E concentrations. Heterogeneity was quantitatively assessed using the I(2) index. Sensitivity analysis was conducted using the leave-one-out method.
  
  
  RESULTS
  A meta-analysis of data from 8 randomized treatment arms including 504 participants indicated a significant reduction in plasma vitamin E concentrations following statin treatment (WMD: -16.30%, 95% CI: -16.93, -15.98, p < 0.001). However, cholesterol-adjusted vitamin E concentrations (defined as vitamin E:total cholesterol ratio) were found to be improved by statin therapy (WMD: 29.35%, 95% CI: 24.98, 33.72, p < 0.001). Statin therapy was not associated with any significant alteration in LDL vitamin E content (SMD: 0.003, 95% CI: -0.90, 0.90, p = 0.995).
  
  
  CONCLUSIONS
  Findings of the present study suggest that statin therapy has no negative impact on plasma vitamin E concentrations or LDL vitamin E content.
authors.affiliation: Biotechnology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran; Metabolic Research Centre, Royal Perth Hospital, School of Medicine and Pharmacology, University of Western Australia, Perth, Australia.
authors.forename: Amirhossein
authors.initials: A
authors.lastname: Sahebkar
authors.affiliation: Biomedical Research Unit, Mexican Social Security Institute, Durango, Mexico. Electronic address: luis_simental81@hotmail.com.
authors.forename: Luis E
authors.initials: LE
authors.lastname: Simental-Mendía
authors.affiliation: Dipartimento di Scienze Cliniche Specialistiche ed Odontostomatologiche (DISCO), Università Politecnica delle Marche, Italy.
authors.forename: Gianna
authors.initials: G
authors.lastname: Ferretti
authors.affiliation: Dipartimento di Scienze della Vita e dell'Ambiente (DISVA), Università Politecnica delle Marche, Italy.
authors.forename: Tiziana
authors.initials: T
authors.lastname: Bacchetti
authors.affiliation: The Vascular Biology Unit, Queensland Research Centre for Peripheral Vascular Disease, College of Medicine and Dentistry, James Cook University, Townsville, QLD 4811, Australia; Department of Vascular and Endovascular Surgery, The Townsville Hospital, Townsville, Queensland 4814 Australia. Electronic address: jonathan.golledge@jcu.edu.au.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Golledge
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D050197:Atherosclerosis / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy*; D015415:Biomarkers / Q000097:blood; D050171:Dyslipidemias / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy*; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D008055:Lipids / Q000097:blood*; D016032:Randomized Controlled Trials as Topic; D016896:Treatment Outcome; D014810:Vitamin E / Q000097:blood*
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D008055:Lipids; D014810:Vitamin E
keywords: Alpha-tocopherol; Cardiovascular disease; Dyslipidemia; Hydroxymethylglutaryl CoA reductase inhibitors; Lipoprotein