[A population study of long-term salt restriction in mild hypertensives].

We all agree to the importance of the salt restriction in the prevention and the treatment of hypertension. But it is not easy to teach the way to reduce salt intake in each person or patient. And we also not confident that how long could they maintain the low salt diet. In this study we investigate following problems, 1) Can the salt intake be reduced in public population? 2) Can blood pressure be lowered by reducing salt intake in mildly hypertensive individuals? 3) If the desired changes are obtained, can they be preserved for a long time? and 4) Are there any difference in the amount of the salt intake between hypertensives and normotensives? One hundred and forty subjects from 23,940 people in whom borderline to mild hypertension was found at group medical examinations in each district, where a total of 29,940 people were examined, were registered to a educational course of new salt-restriction program. Salt intake was estimated from salt measurement in 24-hour urine samples. Educational program was composed of many lectures, sampling party and individualized consultations about dietary problems, using an original dietary questionnaire list. The results were as follows: In short-term (2.5 months) after the initial education, sodium intake reduced from 235.1 +/- 110.8 mmol/day to 161.4 +/- 85.0 mmol/day (p less than 0.001). The systolic and diastolic blood pressure also fell significantly in borderline hypertensives (from 148 +/- 7/87 +/- 5 mmHg to 141 +/- 12/85 +/- 7 mmHg, p less than 0.001) and hypertensives (from 165 +/- 13/99 +/- 8 mmHg to 157 +/- 15/95 +/- 8 mmHg, p less than 0.001) but they did not change in normotensives (from 133 +/- 6/80 +/- 6 mmHg to 131 +/- 9/82 +/- 8 mmHg). In long-term (range from 12 to 36 months) observation, low salt diet (167.6 +/- 72 mmol/day) and a fall in blood pressure were also maintained in borderline (142 +/- 2/85 +/- 7 mmHg, p less than 0.001) to hypertensive population (156 +/- 14/93 +/- 8 mmHg, p less than 0.001), and in the normotensive population, no change in blood pressure was observed (134 +/- 13/82 +/- 9 mmHg). Hypertensives tended to show higher sodium intake than normotensives (206 +/- 101 mmol/day vs. 199.0 +/- 96, p less than 0.005), and also show higher sodium/potassium ratio than normotensives and borderline hypertensives (4.3 +/- 2.3 vs. 3.6 +/- 1.6 and 3.8 +/- 1.8, p less than 0.005).(ABSTRACT TRUNCATED AT 400 WORDS)