Low, High Sodium Intake Tied to Mortality Risk
Consistently reduced risk for all-cause mortality with usual versus low sodium intake.
Low and high sodium intake are associated with increased mortality, according to a meta-analysis published online in the American Journal of Hypertension.
Niels Graudal, M.D., from Copenhagen University Hospital in Denmark, and colleagues conducted a meta-analysis to examine the correlation between sodium exposure and incidence of all-cause mortality (ACM) and cardiovascular disease events (CVDEs).
Data were included from 23 cohort studies and two follow-up studies of randomized clinical trials, involving 274,683 individuals. Dietary intake of sodium was classified as low (<115 mmol), usual (low usual: 115 to 165 mmol; high usual: 166 to 215 mmol), and high (>215 mmol).
The researchers found that the risks of ACM and CVDEs were reduced in usual versus low sodium intake (hazard ratio [HR], 0.91 [95 percent confidence interval (CI), 0.82 to 0.99] and 0.90 [95 percent CI, 0.82 to 0.99], respectively) and were elevated in high versus usual sodium intake (HR, 1.16 [95 percent CI, 1.03 to 1.30] and 1.12 [95 percent CI, 1.02 to 1.24], respectively).
After adjustment for multiple confounders there was a consistent decrease in ACM risk for usual versus low sodium intake (HR, 0.86; 95 percent CI, 0.81 to 0.92), but no consistent increase was seen with high versus usual sodium intake (HR, 1.04; 95 percent CI, 0.91 to 1.18). The number of events was stable within the usual sodium intake range (high usual versus low usual sodium: HR, 0.98; 95 percent CI, 0.92 to 1.03).
"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," the authors write.