Epidemiological studies demonstrate an inverse association between serum magnesium and incidence of cardiovascular disease. Diuretics commonly cause hypomagneseamia.
We evaluated effects of magnesium supplementation on blood pressure (BP) and vascular function in thiazide-treated hypertensive women in a randomized, double-blind, clinical trial. Hypertensive women (40–65 years) on hydrochlorothiazide and mean 24-h BP at least 130/80 mmHg were divided into placebo and supplementation (magnesium chelate 600 mg/day) groups. Patients were evaluated for nutritional and biochemical parameters, office and ambulatory blood pressure monitoring, brachial flow-mediated dilatation (FMD), peripheral arterial tonometry, assessment of carotid intima–media thickness, central hemodynamic parameters and pulse wave velocity at inclusion and after 6-month follow-up.
The magnesium group had a significant reduction in SBP (144 ± 17 vs. 134 ± 14 mmHg, P = 0.036) and DBP (88 ± 9 vs. 81 ± 8 mmHg, P = 0.005) at 6 months, without effect on plasma glucose, lipids, or arterial stiffness parameters. The placebo group showed a significant increase in carotid intima-media thickness (0.78 ± 0.13 vs. 0.89 ± 0.14 mm, P = 0.033) without change in the magnesium group (0.79 ± 0.16 vs. 0.79 ± 0.19 mm, P = 0.716) after 6 months. The magnesium group demonstrated a significant increase in variation of FMD vs. the placebo group (+3.7 ± 2.1 vs. 2.4 ± 1.2%, P = 0.015). There was a significant correlation between the intracellular magnesium variation and FMD (r = 0.44, P = 0.011).
Magnesium supplementation was associated with better BP control, improved endothelial function and amelioration of subclinical atherosclerosis in these thiazide-treated hypertensive women.
aDepartment of Clinical Medicine, Rio de Janeiro State University
bSchool of Nutrition, Federal University of the State of Rio de Janeiro, Rio de Janeiro, Brazil
cInstitute of Cardiovascular and Medical Sciences, British Heart Foundation Glasgow Cardiovascular Research Centre, University of Glasgow, UK
Correspondence to Professor Mario F. Neves, Department of Clinical Medicine, Rio de Janeiro State University, Av. 28 de Setembro, 77 sala 329-Rio de Janeiro, Zip Code: 20551-030, Brazil. Tel: +55 21 2868 8485; e-mail: email@example.com
Abbreviations: Aix, augmentation index; FMD, flow-mediated dilation; HDL, high-density lipoprotein; homa, homeostatic model assessment; IMT, intima-media thickness; LDL, Low-density lipoprotein; MAP, mean arterial pressure; PAT, peripheral arterial tonometry; PWV, pulse wave velocity
Received 21 December, 2015
Revised 4 August, 2016
Accepted 3 September, 2016