Magnesium and health outcomes: An umbrella review of systematic reviews and meta-analyses of observational and intervention studies

Purpose: To map and grade all health outcomes associated with magnesium (Mg) intake and supplementation using an umbrella review. Methods: Umbrella review of systematic reviews with meta-analyses of observational studies and randomized controlled trials (RCTs) using placebo/no intervention as control group. We assessed meta-analyses of observational studies based on random-effect summary effect sizes and their p values, 95% prediction intervals, heterogeneity, small-study effects and excess significance. For meta-analyses of RCTs, outcomes with a random-effect p value < 0.005 and a high-GRADE assessment were classified as strong evidence. Results: From 2048 abstracts, 16 meta-analyses an…