Magnesium Supplementation and Blood Pressure Reduction

Study Overview
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Brief Summary
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This double-blind, placebo-controlled randomized clinical trial will test whether a magnesium glycinate supplement (480 mg/day) taken for 12 weeks lowers blood pressure.

Detailed Description
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This double-blind, placebo-controlled randomized clinical trial will test whether a magnesium glycinate supplement (480 mg/day) taken for 12 weeks lowers blood pressure in 60 adults aged 40-69 who have elevated blood pressure or stage 1 hypertension and are not taking anti-hypertensive medication. Animal studies, epidemiologic studies, and small randomized trials suggest that supplemental Mg may reduce blood pressure, but the evidence is not definitive. Eligibility to participate in the trial will be determined by a 2-stage screening process -- completion of a pre-screening form online followed by an in-person screening clinic visit. Eligible participants will assigned by chance (like a coin toss) to daily magnesium or to placebo and will receive a supply of study capsules via U.S. mail. Participants will take 4 study capsules per day (2 capsules in the morning and 2 capsules in the evening). Assessments at the screening visit include seated blood pressure; 24-hour ambulatory blood pressure (monitor will be worn by the participant for 24 hours and then returned via mail); pulse; weight, height, waist and hip circumference measurements; fasting blood and urine collection; and health and diet questionnaires. Participants will return for clinic visits at 6 weeks and at 12 weeks to assess these measures, including 24-hour ambulatory blood pressure.

Official Title
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Trial of Magnesium Supplementation and Blood Pressure Reduction Among Adults With Untreated High Blood Pressure

Conditions
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Blood Pressure

Intervention / Treatment
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* Dietary Supplement: magnesium glycinate supplement
* Dietary Supplement: placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Self-report of systolic blood pressure 120-139 mmHg or diastolic blood pressure 80-89 mmHg at prescreening Measured seated systolic blood pressure 120-149 mmHg or measured seated diastolic blood pressure 80-94 mmHg at screening visit Body mass index less than 35 kg/m2 Total Mg intake from supplements of no more than 100 mg/day Willing to maintain current diet and supplement use patterns during the intervention period Exclusion Criteria: History of antihypertensive use History of cardiovascular disease (myocardial infarction, stroke, revascularization [coronary artery bypass graft or percutaneous transluminal coronary angioplasty], or angina pectoris) History of invasive cancer diagnosed within the last 5 years (non-melanoma skin cancer permitted) History of type 1 or 2 diabetes History of renal disease History of kidney failure History of dialysis History of pancreatitis History of inflammatory bowel disease History of hypermagnesemia Women who are pregnant, nursing, or intend to become pregnant during the treatment period Plan to relocate out of Boston area within the next year Unwillingness and/or inability to swallow 4 pills per day Inability to provide written informed consent Excessive antacid or laxative use within the past 3 months

Ages Eligible for Study
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Minimum Age: 40 Years
Maximum Age: 69 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: magnesium<br>magnesium glycinate supplement, 480 mg/day | Dietary Supplement: magnesium glycinate supplement<br>* magnesium glycinate (480 mg/day)<br>|
| Placebo Comparator: placebo<br>placebo supplement | Dietary Supplement: placebo<br>* placebo<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in seated blood pressure from baseline to 12 weeks |  | 12 weeks | 
| Change in 24-hour ambulatory blood pressure from baseline to 12 weeks |  | 12 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in plasma renin activity level from baseline to 12 weeks |  | 12 weeks | 
| Change in angiotensin II level from baseline to 12 weeks |  | 12 weeks | 
| Change in aldosterone level from baseline to 12 weeks |  | 12 weeks | 
| Change in creatinine level from baseline to 12 weeks |  | 12 weeks | 
| Change in high-sensitivity C-reactive protein level from baseline to 12 weeks |  | 12 weeks | 
| Change in glucose level from baseline to 12 weeks |  | 12 weeks | 
| Change in insulin level from baseline to 12 weeks |  | 12 weeks | 
| Change in hemoglobin A1c level from baseline to 12 weeks |  | 12 weeks |