title: Effects of Magnesium Supplementation on Blood Pressure: A Meta-Analysis of Randomized Double-Blind Placebo-Controlled Trials.
abstract: The antihypertensive effect of magnesium (Mg) supplementation remains controversial. We aimed to quantify the effect of oral Mg supplementation on blood pressure (BP) by synthesizing available evidence from randomized, double-blind, placebo-controlled trials. We searched trials of Mg supplementation on normotensive and hypertensive adults published up to February 1, 2016 from MEDLINE and EMBASE databases; 34 trials involving 2028 participants were eligible for this meta-analysis. Weighted mean differences of changes in BP and serum Mg were calculated by random-effects meta-analysis. Mg supplementation at a median dose of 368 mg/d for a median duration of 3 months significantly reduced systolic BP by 2.00 mm Hg (95% confidence interval, 0.43-3.58) and diastolic BP by 1.78 mm Hg (95% confidence interval, 0.73-2.82); these reductions were accompanied by 0.05 mmol/L (95% confidence interval, 0.03, 0.07) elevation of serum Mg compared with placebo. Using a restricted cubic spline curve, we found that Mg supplementation with a dose of 300 mg/d or duration of 1 month is sufficient to elevate serum Mg and reduce BP; and serum Mg was negatively associated with diastolic BP but not systolic BP (all P<0.05). In the stratified analyses, a greater reduction in BP tended to be found in trials with high quality or low dropout rate (all P values for interaction <0.05). However, residual heterogeneity may still exist after considering these possible factors. Our findings indicate a causal effect of Mg supplementation on lowering BPs in adults. Further well-designed trials are warranted to validate the BP-lowering efficacy of optimal Mg treatment.
authors.affiliation: From the Department of Epidemiology, Richard M. Fairbanks School of Public Health, Indiana University (X.Z., Y.S.); Department of Endocrinology, Beijing Pinggu Hospital, Beijing, China (Y.L.); Department of Medicine, Division of Cardiovascular Medicine, Stanford University, CA (L.C.D.G.); Center for Magnesium Education and Research, Pahoa, HI (A.R.); Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada (J.W.); and Department of Epidemiology, School of Medicine, Fukushima Medical University, Fukushima, Japan (W.Z.).
authors.forename: Xi
authors.initials: X
authors.lastname: Zhang
authors.affiliation: From the Department of Epidemiology, Richard M. Fairbanks School of Public Health, Indiana University (X.Z., Y.S.); Department of Endocrinology, Beijing Pinggu Hospital, Beijing, China (Y.L.); Department of Medicine, Division of Cardiovascular Medicine, Stanford University, CA (L.C.D.G.); Center for Magnesium Education and Research, Pahoa, HI (A.R.); Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada (J.W.); and Department of Epidemiology, School of Medicine, Fukushima Medical University, Fukushima, Japan (W.Z.).
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Li
authors.affiliation: From the Department of Epidemiology, Richard M. Fairbanks School of Public Health, Indiana University (X.Z., Y.S.); Department of Endocrinology, Beijing Pinggu Hospital, Beijing, China (Y.L.); Department of Medicine, Division of Cardiovascular Medicine, Stanford University, CA (L.C.D.G.); Center for Magnesium Education and Research, Pahoa, HI (A.R.); Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada (J.W.); and Department of Epidemiology, School of Medicine, Fukushima Medical University, Fukushima, Japan (W.Z.).
authors.forename: Liana C
authors.initials: LC
authors.lastname: Del Gobbo
authors.affiliation: From the Department of Epidemiology, Richard M. Fairbanks School of Public Health, Indiana University (X.Z., Y.S.); Department of Endocrinology, Beijing Pinggu Hospital, Beijing, China (Y.L.); Department of Medicine, Division of Cardiovascular Medicine, Stanford University, CA (L.C.D.G.); Center for Magnesium Education and Research, Pahoa, HI (A.R.); Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada (J.W.); and Department of Epidemiology, School of Medicine, Fukushima Medical University, Fukushima, Japan (W.Z.).
authors.forename: Andrea
authors.initials: A
authors.lastname: Rosanoff
authors.affiliation: From the Department of Epidemiology, Richard M. Fairbanks School of Public Health, Indiana University (X.Z., Y.S.); Department of Endocrinology, Beijing Pinggu Hospital, Beijing, China (Y.L.); Department of Medicine, Division of Cardiovascular Medicine, Stanford University, CA (L.C.D.G.); Center for Magnesium Education and Research, Pahoa, HI (A.R.); Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada (J.W.); and Department of Epidemiology, School of Medicine, Fukushima Medical University, Fukushima, Japan (W.Z.).
authors.forename: Jiawei
authors.initials: J
authors.lastname: Wang
authors.affiliation: From the Department of Epidemiology, Richard M. Fairbanks School of Public Health, Indiana University (X.Z., Y.S.); Department of Endocrinology, Beijing Pinggu Hospital, Beijing, China (Y.L.); Department of Medicine, Division of Cardiovascular Medicine, Stanford University, CA (L.C.D.G.); Center for Magnesium Education and Research, Pahoa, HI (A.R.); Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada (J.W.); and Department of Epidemiology, School of Medicine, Fukushima Medical University, Fukushima, Japan (W.Z.).
authors.forename: Wen
authors.initials: W
authors.lastname: Zhang
authors.affiliation: From the Department of Epidemiology, Richard M. Fairbanks School of Public Health, Indiana University (X.Z., Y.S.); Department of Endocrinology, Beijing Pinggu Hospital, Beijing, China (Y.L.); Department of Medicine, Division of Cardiovascular Medicine, Stanford University, CA (L.C.D.G.); Center for Magnesium Education and Research, Pahoa, HI (A.R.); Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada (J.W.); and Department of Epidemiology, School of Medicine, Fukushima Medical University, Fukushima, Japan (W.Z.). yiqsong@iu.edu.
authors.forename: Yiqing
authors.initials: Y
authors.lastname: Song
mesh_terms: D000959:Antihypertensive Agents / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects*; D001795:Blood Pressure Determination; D019587:Dietary Supplements; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy; D008274:Magnesium / Q000097:blood / Q000494:pharmacology; D016032:Randomized Controlled Trials as Topic
chemical_list: D000959:Antihypertensive Agents; D008274:Magnesium
keywords: blood pressure; hypertension; magnesium; meta-analysis; randomized controlled trial