Compared With Usual Sodium Intake, Low- And Excessive-Sodium Diets Are Associated With Increased Mortality: A Meta-Analysis

Am J Hypertens. 2014 Sep;27(9):1129-37. doi: 10.1093/ajh/hpu028. Epub 2014 Mar 20.

Abstract

Background: The effect of sodium intake on population health remains controversial. The objective was to investigate the incidence of all-cause mortality (ACM) and cardiovascular disease events (CVDEs) in populations exposed to dietary intakes of low sodium (<115 mmol), usual sodium (low usual sodium: 115-165 mmol; high usual sodium: 166-215 mmol), and high sodium (>215 mmol).

Methods: The relationship between individual measures of dietary sodium intake vs. outcome in cohort studies and randomized controlled trials (RCTs) measured as hazard ratios (HRs) were integrated in meta-analyses.

Results: No RCTs in healthy population samples were identified. Data from 23 cohort studies and 2 follow-up studies of RCTs (n = 274,683) showed that the risks of ACM and CVDEs were decreased in usual sodium vs. low sodium intake (ACM: HR = 0.91, 95% confidence interval (CI) = 0.82-0.99; CVDEs: HR = 0.90, 95% CI = 0.82-0.99) and increased in high sodium vs. usual sodium intake (ACM: HR = 1.16, 95% CI = 1.03-1.30; CVDEs: HR = 1.12, 95% CI = 1.02-1.24). In population representative samples adjusted for multiple confounders, the HR for ACM was consistently decreased in usual sodium vs. low sodium intake (HR = 0.86; 95% CI = 0.81-0.92), but not increased in high sodium vs. usual sodium intake (HR = 1.04; 95% CI = 0.91-1.18). Within the usual sodium intake range, the number of events was stable (high usual sodium vs. low usual sodium: HR = 0.98; 95% CI = 0.92-1.03).

Conclusions: Both low sodium intakes and high sodium intakes are associated with increased mortality, consistent with a U-shaped association between sodium intake and health outcomes.

Keywords: blood pressure; cardiovascular disease; diet; hypertension; meta-analysis; mortality; salt; sodium chloride; stroke..

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Blood Pressure*
  • Chi-Square Distribution
  • Diet, Sodium-Restricted / adverse effects
  • Diet, Sodium-Restricted / mortality*
  • Disease-Free Survival
  • Health Status
  • Humans
  • Hypertension / diet therapy*
  • Hypertension / etiology
  • Hypertension / mortality*
  • Hypertension / physiopathology
  • Odds Ratio
  • Recommended Dietary Allowances
  • Risk Assessment
  • Risk Factors
  • Sodium Chloride, Dietary / adverse effects*
  • Treatment Outcome

Substances

  • Sodium Chloride, Dietary