本態性高血圧症に対する塩分制限と体重減少の効果

Abstract

We set out to establish whether dietary sodium restriction is feasible and effective in the treatment of essential hypertension on general practice.Fifty-six patients with mild to moderate essential hypertension in outpatient clinic, whose average blood pressure was 169±20/103±8.9mmHg and average relative body-weight was 1.25 (range 0.93-1.95) were allocated to 3 groups by the reduction of urinary sodium-excretion and/or bodyweight after the dietary instruction for hypertension. These patients on non-medication for hypertension were randomly instructed on how to reduce sodium intake or energy intake by metabolic ward dietician. He checked the patients about the compliance of dietary instruction using a questionnaire, and a change of urinary sodium-excretion and body weight at every 6 weeks for 12 weeks.50% of the patients, whose 24-hour urinary sodium-excretion were decreased without a decrease in body-weight, were effective on blood pressure. In 7 of 8 effective patients, 24-hour urinary NaCl-excretion before instruction were 12g or more and the magnitude of a reduction of urinary NaCl excretion was more than 3g/day.On the other hand, only 30% of patients whose body-weight decreased without a decrease in sodium-excretion, were effective on systolic pressure. But urinary sodium-excretion in this group increased, especially that in non-effective patients was higher than in effective patients and plasma aldosterone in non-effective patients significantly decreased from 10.0±2.6 to 8.5±3.4ng/dl (p<0.05).68.8% of patients with decrease in both sodiumexcretion in urine and body-weight were effective, especially frequency of the patients with decrease in diastric pressure was significantly high (χ2=5.11, p<0.05). Though plasma aldosterone level did not change after decrease in both sodium excretion and body-weight, plasma insulin level significantly decreased in only effective patients (p<0.05).In 26 of all patient with decrease in body weight, fasting plasma insulin level were 7μU/ml or more before dietary instruction. 12 of 15 patients, whose plasma insulin level decreased in 2μU/ml or more after dieary instruction, were decreased in blood pressure.Conclusion: The dietary salt restriction which were reducted by 3g/day or more may be effective to hypertension when hypertensive patients have over 12g/24-hour urinary NaCl excretion. But it may be necessary in an effectiveness of diastric hypertension to make body weight reduction and the effect of weight-reduction on hypertension appeared when relatively high concentration of plasma insulin make decrease.