Supplemental Vitamins and Minerals for CVD Prevention and Treatment: Systematic Review and Meta-analyses of the Data (Meta-analyses and RCTs) Published Since 2012

Search strategy:

A literature search of the Cochrane Library, Medline and PubMed will be conducted with the following search terms: "dietary supplements or supplement*" AND "cardiovascular disease or myocardial infarction or stroke or cardiovascular death or mortality or all-cause mortality or death." Specific searches will be conducted for individual supplements and included multivitamins, antioxidants, vitamin A, β-carotene, B1, B2, B3 (niacin), B6, B10 (folic acid), B-complex, C, D and E, calcium, iron, zinc, magnesium and selenium. The search will be limited to meta-analyses and RCTs.

Analysis:

Full article review and data extraction will be conducted by two independent investigators, with all disparities reconciled through consensus. The extracted data will include number of cases and total participants/population for the intervention and control group.

Data will be analyzed using Review Manager (RevMan) version 5.3 (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, Denmark) and publication bias will be conducted using STATA software, version 13.0 (College Station, TX, USA). Heterogeneity will be assessed using the Cochran Q statistic at p<0.1 and quantified by the I² statistic. Publication bias will be investigated by visual inspection of funnel plots and quantitative assessment using Begg's and Egger's tests where p<0.05 is considered evidence of small study effects. If <10 trials are available in a meta-analysis, publication bias analysis will not be assessed due to insufficient power.