Family-Based Randomized Trial to Detect Effects on Blood Pressure of a Salt Substitute Containing Potassium and Calcium in Hypertensive Adolescents

BACKGROUND Potassium and calcium are important in blood pressure (BP) regulation. The aim of this study was to test the effects on BP of adding potassium and calcium to dietary salt. METHODS A total of 325 adolescents selected with high BP (systolic BP (SBP) >= 90th percentile by age and sex) along with 978 family members. The adolescents were randomized into three groups by coin toss, and their families (300 total) were also allocated to the three groups: one in which 10 mmol of potassium and 10 mmol of calcium were added to the cooking salt, one encouraged to follow a salt-restricted diet, and a control group. In the salt-restricted group, salt intake was decreased gradually through health-behavior education to reach the goal of 50-100 mmol per person per day at 2 years. No intervention took place in for the control group. Salt sensitivity was determined by a volume expansion and contraction protocol at the beginning of the study. The three groups were followed up every 6 months for 2 years. RESULTS At 2 years, systolic and diastolic blood pressure (SBP/DBP) had decreased by 5.9/2.8 mm Hg (4.7/3.6%) in the added-potassium-and-calcium group and by 5.8/1.0 mm Hg (4.8/1.4%) in the salt-restricted group; the values rose in the control group by 1.3/2.3 mm Hg (1.1/1.8%). There was no difference between the added-potassium-and-calcium group and the restricted-salt group (P = 0.24), but both differed significantly from the controls (P < 0.05). Similar changes in BP were found in family members. Subgroup analysis showed that the BP in salt-sensitive (SS) subjects decreased more than in the non-salt-sensitive (NSS) group (P < 0.05). CONCLUSION A salt substitute containing potassium and calcium was as effective as sodium restriction in reducing BP in hypertensive adolescents and their families in a that rural Chinese community. Am J Hypertens 2009;22:943-947 (C) 2009 American Journal of Hypertension, Ltd.