P1691Impact of dose and duration of dietary salt reduction on blood pressure levels: systematic review and meta-analysis of randomised trials
Bibliographic record
Abstract
Abstract Background Authoritative medical and public health agencies in most countries advise to reduce population dietary salt intake to under 5–6 g/day as a strategy for preventing high blood pressure and cardiovascular disease. However, there is still dispute about whether salt reduction should be adopted by all populations. In addition, the effect of duration of dietary salt reduction has not been sufficiently investigated. Purpose To understand the effect of dietary salt reduction on blood pressure and the impact of intervention duration. Methods A systematic review and meta-analysis was conducted. Randomized controlled trials that allocated participants to low and high salt intake, without confounding from unequal concomitant interventions, were included. We excluded studies done in individuals younger than 18 years, pregnant women, individuals with renal disease or heart failure, and studies with sodium excretion estimated from spot urine. Random effect meta-analysis was used to generate pooled estimates of the effect on 24-hour urinary sodium excretion, systolic and diastolic blood pressure. Multivariate meta-regression was used to quantify the dose response effect of dietary salt on blood pressure change and to understand the impact of the intervention duration. Results 125 studies were included with 162 data points extracted. Ninety-nine data points (61%) had interventions under 4 weeks. Overall, 24-hour urinary sodium excretion changed by −141 mmol (95% CI: −156; −126), systolic blood pressure changed by −4.4 mm Hg (95% CI: −5.2; −3.7) and diastolic blood pressure changed by −2.4 mm Hg (95% CI: −2.9; −1.9). Sodium reduction resulted in a significant decrease of systolic blood pressure in all subgroups except in participants with low baseline sodium intake (<109 mmol) (Figure 1). Each 100 mmol reduction of sodium was associated with 2.7 mm Hg (95% CI: 1.0; 4.4; p=0.002) reduction of systolic blood pressure and 1.2 mm Hg (95% CI: 0.0; 2.4; p=0.046) reduction of diastolic blood pressure after adjusting for intervention duration, age, sex, race, baseline blood pressure, baseline sodium intake and interaction between age and baseline blood pressure. For the same amount of salt reduction, a 10 mm Hg higher baseline systolic blood pressure would result in 2.5 mm Hg greater reduction of systolic blood pressure. There is not enough evidence to show the impact of intervention duration. Figure 1 Conclusions Our meta-analysis showed that sodium reduction could reduce blood pressure in all adult populations regardless of age, sex and race. The effect of salt reduction on systolic blood pressure increases with higher baseline blood pressure. Further studies, designed to investigate the impact of intervention duration, are needed to understand the significance of the duration. Acknowledgement/Funding None
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.020 | 0.050 |
| Meta-epidemiology (narrow) | 0.003 | 0.002 |
| Meta-epidemiology (broad) | 0.022 | 0.042 |
| Bibliometrics | 0.005 | 0.007 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.004 | 0.003 |
| Open science | 0.003 | 0.002 |
| Research integrity | 0.003 | 0.003 |
| Insufficient payload (model declined to judge) | 0.007 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".