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Calcium and magnesium in essential hypertension
1MRC Blood Pressure Unit, Western Infirmary, Glasgow, U.K.
Insights
Essential hypertension is linked to altered calcium and magnesium metabolism. Hypertensive patients showed decreased urinary magnesium excretion, inversely correlating with blood pressure, suggesting a role for magnesium in hypertension management.
Area of Science:
- Nephrology
- Cardiovascular Medicine
- Endocrinology
Background:
- Disturbances in calcium metabolism are implicated in hypertension.
- Previous research suggests a link between mineral metabolism and blood pressure regulation.
Purpose of the Study:
- To investigate plasma and serum concentrations of ionized calcium, total calcium, magnesium, and renin in patients with essential hypertension.
- To determine urinary excretion of calcium, magnesium, and sodium in hypertensive and control subjects.
Main Methods:
- Measurements of serum and plasma electrolytes and hormones in 38 hypertensive patients and matched controls.
- Analysis of urinary calcium, magnesium, and sodium excretion over 24 hours.
- Correlation analysis between mineral concentrations, urinary excretion, and blood pressure parameters.
Main Results:
- No significant difference in serum ionized or total calcium between hypertensive and control groups.
- A weak positive correlation was observed between serum ionized calcium and systolic pressure.
- Significantly lower urinary magnesium excretion was found in hypertensive subjects, inversely correlating with blood pressure.
Conclusions:
- Essential hypertension is associated with altered magnesium metabolism, characterized by reduced urinary excretion.
- Magnesium homeostasis may play a role in blood pressure regulation, warranting further investigation.
- While calcium levels were not significantly different, the observed correlations suggest potential links between mineral metabolism and hypertension.
Abstract:
1. Because disturbances of calcium metabolism have been described in hypertension, measurements of plasma and serum concentrations of ionized calcium, total calcium, magnesium and renin were made in 38 patients with essential hypertension and age- and sex-matched control subjects. Urinary excretion of calcium, magnesium and sodium was also determined. 2. The mean serum concentration of ionized calcium was 1.23 +/- 0.04 (SD) mmol/l in the hypertensive group and 1.21 +/- 0.03 mmol/l in controls, and results were similar after correction for pH. There was a weak positive correlation between serum ionized calcium (pH 7.4) and systolic pressure (r = 0.26, P less than 0.02), but no correlation with plasma renin concentration. 3. Although the difference between serum total calcium concentration in the hypertensive (2.29 +/- 0.09 mmol/l) and control (2.26 +/- 0.07 mmol/l) subjects was not significant, there was a significant correlation between total calcium and systolic pressure (r = 0.23, P less than 0.05) which was maintained after correction for other variables. 4. There were no differences in plasma concentrations of parathyroid hormone or 1,25-dihydroxycholecalciferol between hypertensive and control subjects. 5. The hypertensive group showed higher urinary excretion of calcium (5.9 +/- 3.0 mmol/24 h) than controls (4.6 +/- 1.7 mmol/24 h), but the difference was not maintained after correction for sodium excretion. 6. Serum concentrations of magnesium were similar in the two groups, but urinary excretion of magnesium was significantly lower in hypertensive (3.7 +/- 1.3 mmol/24 h) than control (4.5 +/- 1.6 mmol/24 h) subjects and there was an inverse correlation between magnesium excretion and blood pressure (r = 0.3-0.35, P less than 0.01).