Advice to reduce dietary salt for prevention of cardiovascular disease
Why the study?
Does advice to restrict dietary sodium reduce blood pressure and cardiovascular events in adults?
Population
3,514 adults from 11 randomized trials
Comparison
Advice to restrict dietary sodium over at least… vs Usual or control diet group
Design
Meta-analysis
Follow-up
6 months to 7 years
Authors
Discussion
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Implication
Minimal long-term BP reductions from sodium advice limit its standalone role in hypertension; extends short-term data by showing effect attenuation at 13-60 months.
Key Points
- To assess the long-term effects of advice to restrict dietary sodium on mortality, cardiovascular events, blood pressure, and medication use in adults with normal or elevated blood pressure.
- Systematic review and random-effects meta-analysis of unconfounded randomized controlled trials evaluating dietary sodium reduction interventions with at least 26 weeks of follow-up.
- Identified 11 trials across three clinical groups: normotensive adults (3 trials, n=2326), untreated hypertensive adults (5 trials, n=387), and treated hypertensive adults (3 trials, n=801), with follow-up durations ranging from six months to seven years.
- Dietary sodium advice reduced urinary 24-hour sodium excretion by 35.5 mmol/24 hours (95% CI, 23.9 to 47.2) and resulted in small reductions in systolic blood pressure by 1.1 mm Hg (95% CI, 0.4 to 1.8) and diastolic blood pressure by 0.6 mm Hg (95% CI, -0.3 to 1.5) at 13 to 60 months.
- Cardiovascular events and all-cause mortality were poorly defined and rarely reported, with only 17 total deaths recorded and evenly distributed between intervention and control arms.
- Participants receiving antihypertensive pharmacotherapy successfully discontinued medication more frequently when assigned to a reduced-sodium diet while maintaining blood pressure control comparable to controls.
Structured PICO
Does advice to restrict dietary sodium reduce blood pressure and cardiovascular events in adults?
P
Population
3,514 adults (2,326 normotensives, 387 untreated hypertensives, and 801 treated hypertensives) from 11 randomized trials
I
Intervention
Advice to restrict dietary sodium over at least 6 months (using intensive behavioural interventions)
C
Comparator
Usual or control diet group
O
Outcome
Long term effects including mortality, cardiovascular events, blood pressure, quality of life, weight, urinary sodium excretion, other nutrients and use of anti-hypertensive medicationssurrogate
Intensive advice to reduce dietary sodium provides only minimal long-term reductions in blood pressure, though it may assist in maintaining lower blood pressure after withdrawing antihypertensive medications.
Limitations
- Deaths and cardiovascular events were inconsistently defined and reported
- Intensive interventions unsuited to primary care or population prevention programmes
Cite This Study
Hooper et al. (2004) studied this question.