Urinary cations and blood pressure--population studies.

The relationship between urinary cations and blood pressure has been examined by means of multiple regression analysis with the inclusion of age, BMI, urinary 24-hour creatinine, heart rate and the 24-hour urinary excretion of Na, K and, in a subsample, of Ca and Mg. In Korea where the Na intake is high and the K intake is low a significant positive relationship was found between 24-hour urinary Na and blood pressure and a negative one between 24-hour urinary K and blood pressure. In Belgium, however, a negative relationship was found between 24-hour urinary Na and the Na/K ratio and blood pressure. In a subsample the 24-hour urinary Mg excretion significantly and negatively correlated with diastolic blood pressure both in men (slope -0.245 mm Hg/mmol Mg) and in women (slope -0.525 mm Hg/mmol Mg) while no significant relationship was found with 24-hour urinary Ca. Further study of the importance of Mg for blood pressure regulation is warranted.