Salt and Cardiovascular Disease: Clinical and Epidemiological Evidence

INTERSALT Cooperative Research Group. INTERSALT; an international study of electrolyte excretion and blood pressure. Results for 24 hour urinary sodium and potassium excretion. BMJ 1988; 297: 319–328.

A major international epidemiological study on levels of electrolytes and other factors related to blood pressure. The daily average intake of sodium by individual subjects, determined by measuring urinary excretion of sodium, was significantly related to blood pressure. There was a positive relationship between intake of sodium and the change in the blood pressure with age.

Elliott P Stamler J Nichols R Dyer AR Stamler R Marmot M . for the Intersalt Cooperative Research Group. Intersalt revisited: further analyses of 24 hour sodium excretion and blood pressure within and across populations. BMJ 1996; 312: 1249–1253.

In this further analysis of the Intersalt data [1] the relationship between blood pressure and sodium was reassessed by within-population and cross-population multiple-regression analyses, with correction for regression dilution bias. An increase in level of dietary sodium was associated with higher median levels of blood pressure both in the within-population and in cross-population analyses and there was a positive association with age.

Law MR Frost MD Wald NJ. By how much does salt reduction lower blood pressure? I. Analysis of observational data among populations. BMJ 1991; 302: 811–815.

Authors of this overview analysis of observational data for 24 different communities (47 000 people) demonstrated that blood pressure varies according to intake of sodium. The change in blood pressure, for a given change in intake of sodium, was related to age and the magnitude of the initial blood pressure.

Alderman MH Madhavan S Cohen H Sealey JE Laragh JH. Low urinary sodium is associated with greater risk of myocardial infarction among treated hypertensive men. Hypertension 1995; 25: 1144–1152.

Alderman MH Cohen H Madhavan S. Dietary sodium intake and mortality; the National Health and Nutrition Examination Survey (NHANES I). Lancet 1998; 351: 781–785.

Poulter NK Khaw KT Hopwood BEC Mugambi M Peart WS Rose G . The Kenyan Luo migration study: observations on the initiation of a rise in blood pressure. BMJ 1990; 300: 967–972.

Authors of this controlled longitudinal study observed migrants from rural Kenyan villages, after their migration to an urban environment. Urinary sodium: potassium ratio, pulse rate and weight were found to be important predictors of the rise in blood pressure which occurred in the migrants, compared with the non-migrant controls.

MacGregor GA Markandu ND Best FE Elder DM Cam JM Sagnella GA . Double-blind randomised crossover trial of moderate sodium restriction in essential hypertension. Lancet 1982; I: 352–354.

MacGregor GA Markandu ND Sagnella GA Cappuccio FP. Double-blind study of three sodium intakes and long-term effects of sodium restriction in essential hypertension. Lancet 1989; II: 1244–1247.

Authors of this study of 20 patients with mild hypertension demonstrated that a progressive fall in blood pressure occurred as dietary intake of salt was reduced. A fall in blood pressure of 16 mmHg systolic and 9 mmHg diastolic was observed on going from a high (200 mmol) to a low (50 mmol) daily intake of sodium.

Grobbee DE Hofman A. Does sodium restriction lower blood pressure? BMJ 1986; 293: 27–29.

Law MR Frost MD Wald NJ. By how much does salt reduction lower blood pressure? III. Analysis of data from trials of salt reduction. BMJ 1991; 302: 819–824.

An analysis of the results of 68 crossover trials and 10 randomized controlled trials, estimating that moderate restriction of dietary intake of salt by a Western population would reduce the incidence of strokes by 22% and that of ischaemic heart disease by 16%.

Cutler JA Follmann D Allender PS. Randomized trials of sodium reduction: an overview. Am J Clin Nutr 1997; 65 (suppl 2): 643S–651S.

Hofman A Hazebroek A Valkenburg HA. A randomized trial of sodium intake and blood pressure in newborn infants. JAMA 1983; 250: 370–373.

A double-blind randomized trial of 245 newborn infants assigned to a normal-sodium diet and 231 assigned to a low-sodium diet during the first 6 months of life. Systolic blood pressure was 2.1 mmHg lower in babies in the low-sodium-diet group after 25 weeks.

Geleijnse JM Hofman A Witteman JCM Hazebroek AA Valkenburg HA Grobbee DE. Long-term effects of neonatal sodium restriction on blood pressure. Hypertension 1997; 29: 913–917.

Blood pressure in subjects fed a low-sodium diet during the first 6 months of life remains lower [12]. The adjusted average systolic blood pressure in subjects fed a low-sodium diet during the first 6 months of life was 3.6 mmHg lower and the diastolic blood pressure was 2.2 mmHg lower after 15 years.

Fotherby MD Potter JF. Effects of moderate sodium restriction on clinic and twenty-four hour ambulatory blood pressure in elderly hypertensive subjects. J Hypertens 1993; 11: 657–663.

Geleijnse JM Witteman JC Bak AA den Breeijen JH Grobbee DE. Reduction in blood pressure with a low sodium, high potassium, high magnesium salt in older subjects with mild to moderate hypertension. BMJ 1994; 309: 436–440.

Whelton PK Appel U Espeland MA Applegate WB Ettinger WH Kostis JB . Sodium reduction and weight loss in the treatment of hypertension in older persons. A randomised controlled trial of nonpharmacologic interventions in the elderly (TONE). JAMA 1998; 279: 839–846.

Restriction of dietary intake of sodium, with or without weight loss, reduced blood pressure in a randomized controlled trial of 875 hypertensive patients aged 60–80 years.

Midgley JP Matthew AG Greenwood CMT Logan AG. Effect of reduced dietary sodium on blood pressure: a meta-analysis of randomized controlled trials. JAMA 1996; 275: 1590–1597.

Cappuccio FP Markandu ND Carney C Sagnella GA MacGregor GA. Double-blind randomised trial of modest salt restriction in older people. Lancet 1997; 350: 850–854.

Masugi F Ogihara T Hashizume K Hasegawa T Sakaguchi K Kumahara Y. Changes in plasma lipids and uric acid with sodium loading and sodium depletion in patients with essential hypertension. J Hum Hypertens 1988; 1: 293–298.

Egan BM Weder AB Petrin J Hoffmann RG. Neurohumoral and metabolic effects of short-term dietary NaCl restriction in men. Relationship to salt-sensitivity status. Am J Hypertens 1991; 4: 416–421.

Geleijnse JM Witteman JC Bak AA den Breeijen JH Grobbee DE. Long-term moderate sodium restriction does not adversely affect the HDL/total cholesterol ratio. J Hum Hypertens 1995; 9: 975–979.

Forte JG Miguel JM Miguel MJ de-Padua F Rose G. Salt and blood pressure: a community trial. J Hum Hypertens 1989; 3: 179–184.

Restriction of sodium intake by people in a rural community of approximately 800 adult inhabitants resulted in average falls of 5 mmHg in systolic blood pressure and 5.1 mmHg in diastolic blood pressure compared with a matched control community.

Tian HG Guo ZY Hu G Yu SJ Sun W Pietinen P . Changes in sodium intake and blood pressure in a community-based intervention project in China. J Hum Hypertens 1995; 9: 959–968.

Staessen J Bulpitt CJ Fagard R Joossens JV Lijnen P Amery A. Salt intake and blood pressure in the general population: a controlled intervention trial in two towns. J Hypertens 1988; 6: 965–973.

Schmieder RE Messerli FH Garavaglia GE Nunez BD. Dietary salt intake. A determinant of cardiac involvement in essential hypertension. Circulation 1988; 78: 951–956.

Daniels SD Meyer RA Loggie JMH. Determinants of cardiac involvement in children and adolescents with essential hypertension. Circulation 1990; 82: 1243–1248.

Ferrara LA DeSimone G Pasanisi F Macini M. Left ventricular mass reduction during salt depletion in arterial hypertension. Hypertension 1984; 6: 755–759.

Liebson PR Grandits GA Dianzumba S Prineas RJ Grimm RH Neaton JD . Comparison of five antihypertensive monotherapies and placebo for change in left ventricular mass in patients receiving nutritional-hygienic therapy in the Treatment of Mild Hypertension Study (TOHMS). Circulation 1995; 91: 698–706.

A double-blind placebo-controlled trial of restriction of sodium intake and loss of weight by 844 mildly hypertensive patients. Intervention was associated with a reduction in blood pressure and a significant reduction in left ventricular mass.

Tobian L Hanlon S. High sodium chloride diets injure arteries and raise mortality without raising blood pressure. Hypertension 1990; 15: 900–903.

Perry IJ Beevers DG. Salt intake and stroke: a possible direct effect. J Hum Hypertens 1992; 6: 23–25.

Xie JX Sasaki S Joossens JV Kesteloot H. The relationship between urinary cations obtained from the INTERSALT study and cerebrovascular mortality. J Hum Hypertens 1992; 6: 17–21.

MacGregor GA. Salt-more adverse effects. Am J Hypertens 1997; 10 (suppl 5): 37S–41S.

Barba G Cappuccio FP Russo L Stinga F Iacone R Strazzullo P. Renal failure and blood pressure response to dietary salt restriction in normotensive men. Hypertension 1996; 27: 1160–1164.

A study of 47 healthy male subjects both while eating a high-salt diet and after restriction of salt intake. Sensitivity to salt of individuals was correlated to glomerular filtration rate and absolute proximal reabsorption of sodium during the period of eating a sodium-rich diet.

Benstein JA Feiner HD Parker M Dworkin LD. Superiority of salt restriction over diuretics in reducing renal hypertrophy and injury in uninephrectomized SHR. Am J Physiol 1990; 258: F1675–F1681.

Campese VM Parise M Karubian F Bigazzi R. Abnormal renal haemodynamics in black salt-sensitive patients with hypertension. Hypertension 1991; 18: 805–812.

MacGregor GA Sever PS. Salt-overwhelming evidence but still no action: can a consensus be reached with the food industry? BMJ 1996; 312: 1287–1289.