Reduced dietary salt for the prevention of cardiovascular disease

Abstract

BACKGROUND: This is an update of a Cochrane review that was first published in 2011 of the effects of reducing dietary salt intake, through advice to reduce salt intake or low-sodium salt substitution, on mortality and cardiovascular events. OBJECTIVES: 1. To assess the long-term effects of advice and salt substitution, aimed at reducing dietary salt, on mortality and cardiovascular morbidity. 2. To investigate whether a reduction in blood pressure is an explanatory factor in the effect of such dietary interventions on mortality and cardiovascular outcomes. METHODS:Search methods: We updated the searches of CENTRAL (2013, Issue 4), MEDLINE (OVID, 1946 to April week 3 2013), EMBASE (OVID, 1947 to 30 April 2013 and CINAHL (EBSCO, inception to 1 April 2013) and last ran these on 1 May 2013. We also checked the references of included studies and reviews. We applied no language restrictions. Selection criteria: Trials fulfilled the following criteria: (1) randomised, with follow-up of at least six months, (2) the intervention was reduced dietary salt (through advice to reduce salt intake or low-sodium salt substitution), (3) participants were adults and (4) mortality or cardiovascular morbidity data were available. Two review authors independently assessed whether studies met these criteria. Data collection and analysis: A single author extracted data and assessed study validity, and a second author checked this. We contacted trial authors where possible to obtain missing information. We extracted events and calculated risk ratios (RRs) and 95% confidence intervals (CIs). MAIN RESULTS: Eight studies met the inclusion criteria: three in normotensives (n = 3518) and five in hypertensives or mixed populations of normo-and hypertensives (n = 3766). End of trial follow-up ranged from six to 36 months and the longest observational follow-up (after trial end) was 12.7 years. The risk ratios (RR) for all-cause mortality in normotensives were imprecise and showed no evidence of reduction (end of trial RR 0.67, 95% confidence interval (CI) 0.40 to 1.12, 60 deaths; longest follow-up RR 0.90, 95% CI 0.58 to 1.40, 79 deaths n = 3518) or in hypertensives (end of trial RR 1.00, 95% CI 0.86 to 1.15, 565 deaths; longest follow-up RR 0.99, 95% CI 0.87 to 1.14, 674 deaths n = 3085). There was weak evidence of benefit for cardiovascular mortality (hypertensives: end of trial RR 0.67, 95% CI 0.45 to 1.01, 106 events n = 2656) and for cardiovascular events (hypertensives: end of trial RR 0.76, 95% CI 0.57 to 1.01, 194 events, four studies, n = 3397; normotensives: at longest follow-up RR 0.71, 95% CI 0.42 to 1.20, 200 events; hypertensives: RR 0.77, 95% CI 0.57 to 1.02, 192 events; pooled analysis of six trials RR 0.77, 95%

Salt Intake from Processed Meat Products: Benefits, Risks and Evolving Practices

“…This topic has been controversial for a long time (Volatier & Lafay, ). In particular, there are major differences in the responses of blood pressure to salt intake between normotensive and hypertensive subjects (Adler et al., ; Mente et al., ; Volatier & Lafay, ). The debate remains ongoing because HBP is linked to many other dietary factors (Institute of Medicine (USA) Panel on Dietary Reference Intakes, ).…”

Primary and Secondary Prevention of Ischemic Heart Disease in Women

“…In a review of studies examining the interaction between salt reduction and blood pressure, a significant reduction in both systolic (−7.11 mmHg, 95 % CI −8.81, −5.41, p < 0.0001) and diastolic blood pressure (−3.41, 95%CI −4.29, −2.53, p<0.0001) was seen in both hypertensive and normotensive women with a reduction of salt intake below 5-6 g/day [43]. Although higher salt intake is associated with worse cardiovascular outcomes [44], measures such as advice to reduce salt intake or salt substitutes are only weakly associated with an improvement in cardiovascular mortality and cardiovascular events [45].…”

Does Limiting Salt Intake Prevent Heart Failure? A Critical Appraisal

“…Further analysis of the same dataset revealed a linear 17 % increase in risk of cardiovascular events for every 1 g/ day increase in sodium excretion, albeit of borderline statistical significance (p = 0.054) [74]. These findings have been challenged by a subsequent Cochrane review, including two additional randomized trials [75], which concluded that current data are insufficient to determine if dietary sodium restriction affects cardiovascular morbidity or mortality.…”