Tags

Type your tag names separated by a space and hit enter

Effect of modest salt reduction on blood pressure: a meta-analysis of randomized trials. Implications for public health.
J Hum Hypertens. 2002 Nov; 16(11):761-70.JH

Abstract

Two recent meta-analyses of randomised salt reduction trials have concluded that there is little purpose in reducing salt intake in the general population. However, the authors, as with other previous meta-analyses, included trials of very short duration (eg 1 week or less) and trials of acute salt loading followed by abrupt reductions to very low salt intake (eg from 20 to less than 1 g of salt/day). These acute salt loading and salt depletion experiments are known to increase sympathetic tone, and with salt depletion cause a rise in renin release and, thereby, plasma angiotensin II. These trials are not appropriate, therefore, for helping to inform public health policy, which is for a more modest reduction in salt intake, ie, from a usual intake of approximately 10 to approximately 5 g of salt per day over a more prolonged period of time. We carried out a meta-analysis to assess the effect of a modest salt reduction on blood pressure. Our data sources were MEDLINE, EMBASE, Cochrane library, CINAHL, and the reference lists of original and review articles. We included randomised trials with a modest reduction in salt intake and a duration of 4 or more weeks. Meta-analysis, meta-regression, and funnel plots were performed. A total of 17 trials in hypertensives (n=734) and 11 trials in normotensives (n=2220) were included in our study. The median reduction in 24-h urinary sodium excretion was 78 mmol (equivalent to 4.6 g of salt/day) in hypertensives and 74 mmol in normotensives. The pooled estimates of blood pressure fall were 4.96/2.73+/-0.40/0.24 mmHg in hypertensives (P<0.001 for both systolic and diastolic) and 2.03/0.97+/-0.27/0.21 mmHg in normotensives (P<0.001 for both systolic and diastolic). Weighted linear regression analyses showed a dose response between the change in urinary sodium and blood pressure. A reduction of 100 mmol/day (6 g of salt) in salt intake predicted a fall in blood pressure of 7.11/3.88 mmHg (P<0.001 for both systolic and diastolic) in hypertensives and 3.57/1.66 mmHg in normotensive individuals (systolic: P<0.001; diastolic: P<0.05). Our results demonstrate that a modest reduction in salt intake for a duration of 4 or more weeks does have a significant and, from a population viewpoint, important effect on blood pressure in both hypertensive and normotensive individuals. This meta-analysis strongly supports other evidence for a modest and long-term reduction in population salt intake, and would be predicted to reduce stroke deaths immediately by approximately 14% and coronary deaths by approximately 9% in hypertensives, and reduce stroke and coronary deaths by approximately 6 and approximately 4%, in normotensives, respectively.

Authors+Show Affiliations

Blood Pressure Unit, St George's Hospital Medical School, London, UK.No affiliation info available

Pub Type(s)

Journal Article
Meta-Analysis

Language

eng

PubMed ID

12444537

Citation

He, F J., and G A. MacGregor. "Effect of Modest Salt Reduction On Blood Pressure: a Meta-analysis of Randomized Trials. Implications for Public Health." Journal of Human Hypertension, vol. 16, no. 11, 2002, pp. 761-70.
He FJ, MacGregor GA. Effect of modest salt reduction on blood pressure: a meta-analysis of randomized trials. Implications for public health. J Hum Hypertens. 2002;16(11):761-70.
He, F. J., & MacGregor, G. A. (2002). Effect of modest salt reduction on blood pressure: a meta-analysis of randomized trials. Implications for public health. Journal of Human Hypertension, 16(11), 761-70.
He FJ, MacGregor GA. Effect of Modest Salt Reduction On Blood Pressure: a Meta-analysis of Randomized Trials. Implications for Public Health. J Hum Hypertens. 2002;16(11):761-70. PubMed PMID: 12444537.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Effect of modest salt reduction on blood pressure: a meta-analysis of randomized trials. Implications for public health. AU - He,F J, AU - MacGregor,G A, PY - 2002/06/03/received PY - 2002/06/18/accepted PY - 2002/11/22/pubmed PY - 2003/3/5/medline PY - 2002/11/22/entrez SP - 761 EP - 70 JF - Journal of human hypertension JO - J Hum Hypertens VL - 16 IS - 11 N2 - Two recent meta-analyses of randomised salt reduction trials have concluded that there is little purpose in reducing salt intake in the general population. However, the authors, as with other previous meta-analyses, included trials of very short duration (eg 1 week or less) and trials of acute salt loading followed by abrupt reductions to very low salt intake (eg from 20 to less than 1 g of salt/day). These acute salt loading and salt depletion experiments are known to increase sympathetic tone, and with salt depletion cause a rise in renin release and, thereby, plasma angiotensin II. These trials are not appropriate, therefore, for helping to inform public health policy, which is for a more modest reduction in salt intake, ie, from a usual intake of approximately 10 to approximately 5 g of salt per day over a more prolonged period of time. We carried out a meta-analysis to assess the effect of a modest salt reduction on blood pressure. Our data sources were MEDLINE, EMBASE, Cochrane library, CINAHL, and the reference lists of original and review articles. We included randomised trials with a modest reduction in salt intake and a duration of 4 or more weeks. Meta-analysis, meta-regression, and funnel plots were performed. A total of 17 trials in hypertensives (n=734) and 11 trials in normotensives (n=2220) were included in our study. The median reduction in 24-h urinary sodium excretion was 78 mmol (equivalent to 4.6 g of salt/day) in hypertensives and 74 mmol in normotensives. The pooled estimates of blood pressure fall were 4.96/2.73+/-0.40/0.24 mmHg in hypertensives (P<0.001 for both systolic and diastolic) and 2.03/0.97+/-0.27/0.21 mmHg in normotensives (P<0.001 for both systolic and diastolic). Weighted linear regression analyses showed a dose response between the change in urinary sodium and blood pressure. A reduction of 100 mmol/day (6 g of salt) in salt intake predicted a fall in blood pressure of 7.11/3.88 mmHg (P<0.001 for both systolic and diastolic) in hypertensives and 3.57/1.66 mmHg in normotensive individuals (systolic: P<0.001; diastolic: P<0.05). Our results demonstrate that a modest reduction in salt intake for a duration of 4 or more weeks does have a significant and, from a population viewpoint, important effect on blood pressure in both hypertensive and normotensive individuals. This meta-analysis strongly supports other evidence for a modest and long-term reduction in population salt intake, and would be predicted to reduce stroke deaths immediately by approximately 14% and coronary deaths by approximately 9% in hypertensives, and reduce stroke and coronary deaths by approximately 6 and approximately 4%, in normotensives, respectively. SN - 0950-9240 UR - https://www.unboundmedicine.com/medline/citation/12444537/Effect_of_modest_salt_reduction_on_blood_pressure:_a_meta_analysis_of_randomized_trials__Implications_for_public_health_ L2 - http://dx.doi.org/10.1038/sj.jhh.1001459 DB - PRIME DP - Unbound Medicine ER -