Article type
Abstract
Background
Systematic reviews and meta-analyses (SRMAs) of sodium intake on health have yielded conflicting results, thereby limiting the credibility and strength.
Objective
To assess the impact of reducing dietary sodium on blood pressure (BP), mortality, and major cardiometabolic outcomes based on the highest-quality SRMAs.
Methods
This umbrella review included searches of MEDLINE, EMBASE, Cochrane Database of Systematic Reviews and Web of Science, until January 2021, and update in December 2023, for SRMAs of randomized controlled trials and cohort studies investigated reducing sodium on BP, mortality, and major cardiometabolic outcomes in adults. We assessed methodological quality using a modified version of Assessment of Multiple Systematic Reviews 2 instrument, and rated the certainty of evidence using Grading of Recommendations, Assessment, Development and Evaluation. Where possible, we narratively summarized evidence using 4 population risk strata (very low, low, moderate, high) and computed absolute risk (reduction or increase) for better interpretability.
Results
We included 55 SRMAs; 26 were of moderate or high quality. In the low-risk stratum, lower sodium intake reduced systolic BP by [mean difference in mmHg; moderate to high certainty] -4.76 to -4.26 (general population), -8.69 to -5.74 (hypertension), -8.21 to -6.97 (prehypertension), and -2.00 (overweight), with little to no effect in normotensive individuals, with concordant but smaller effects on diastolic BP. Additionally, lower sodium intake also reduced the risks of all-cause mortality, cardiovascular mortality and stroke in general population (ARR 12 fewer per 1000; 9 fewer per 1000; ARR 5 fewer per 1000; respectively)(moderate to high certainty). In the high-risk stratum, moderate to high certainty evidence indicated that lower sodium intake reduced systolic BP by -6.91 in population with chronic kidney disease, with concordant but smaller effects on diastolic BP. The evidence was very uncertain about the effect of lower sodium intake on all-cause and cardiovascular mortality in population with chronic kidney disease.
Conclusions
Sodium reduction was generally beneficial for blood pressure in low- or high-risk stratum, and reduced the risks of all-cause mortality, cardiovascular mortality, and stroke in low-risk stratum.
Systematic reviews and meta-analyses (SRMAs) of sodium intake on health have yielded conflicting results, thereby limiting the credibility and strength.
Objective
To assess the impact of reducing dietary sodium on blood pressure (BP), mortality, and major cardiometabolic outcomes based on the highest-quality SRMAs.
Methods
This umbrella review included searches of MEDLINE, EMBASE, Cochrane Database of Systematic Reviews and Web of Science, until January 2021, and update in December 2023, for SRMAs of randomized controlled trials and cohort studies investigated reducing sodium on BP, mortality, and major cardiometabolic outcomes in adults. We assessed methodological quality using a modified version of Assessment of Multiple Systematic Reviews 2 instrument, and rated the certainty of evidence using Grading of Recommendations, Assessment, Development and Evaluation. Where possible, we narratively summarized evidence using 4 population risk strata (very low, low, moderate, high) and computed absolute risk (reduction or increase) for better interpretability.
Results
We included 55 SRMAs; 26 were of moderate or high quality. In the low-risk stratum, lower sodium intake reduced systolic BP by [mean difference in mmHg; moderate to high certainty] -4.76 to -4.26 (general population), -8.69 to -5.74 (hypertension), -8.21 to -6.97 (prehypertension), and -2.00 (overweight), with little to no effect in normotensive individuals, with concordant but smaller effects on diastolic BP. Additionally, lower sodium intake also reduced the risks of all-cause mortality, cardiovascular mortality and stroke in general population (ARR 12 fewer per 1000; 9 fewer per 1000; ARR 5 fewer per 1000; respectively)(moderate to high certainty). In the high-risk stratum, moderate to high certainty evidence indicated that lower sodium intake reduced systolic BP by -6.91 in population with chronic kidney disease, with concordant but smaller effects on diastolic BP. The evidence was very uncertain about the effect of lower sodium intake on all-cause and cardiovascular mortality in population with chronic kidney disease.
Conclusions
Sodium reduction was generally beneficial for blood pressure in low- or high-risk stratum, and reduced the risks of all-cause mortality, cardiovascular mortality, and stroke in low-risk stratum.