MedWire News: Results from a meta-analysis have confirmed that high salt intake is associated with elevated risk for stroke and cardiovascular disease (CVD).

Previous studies have linked high salt consumption to increased blood pressure (BP), and increased BP to increased risk for stroke and CVD, but prospective studies directly linking salt intake with stroke and CVD have been inconclusive because of problems in reliably measuring salt consumption.

To estimate the cardiovascular risk posed by high dietary salt intake, Pasquale Strazzullo at the University of Naples, Italy, performed a systematic review and meta-analysis of data from 13 prospective studies of habitual dietary salt intake and incidence of stroke and total CVD.

In their analysis of 19 independent cohort samples from 13 studies, involving 177,025 participants, an increase of 5 g a day in habitual salt intake was associated with a significantly greater risk for stroke (pooled relative risk 1.23; p=0.007).

It was also associated with a nonsignificant increased risk for CVD, at a pooled relative risk of1.14 (p=0.07). The researchers note, however, that after one study with particularly unreliable estimates of sodium intake was excluded on sensitivity analyses, the pooled relative risk for CVD became significant, at 1.17 (p=0.02).

The associations observed were greater the larger the difference in sodium intake and the longer the follow-up.

The researchers report that there was no significant evidence of publication bias, and they warn that uncertainty about the accuracy of measurements of salt intake mean that the effect sizes are likely to be underestimated.

Writing in the British Medical Journal, they conclude: “High salt intake is associated with significantly increased risk of stroke and total CVD.”

They further comment: “These results support the role of a substantial population reduction in salt intake for the prevention of CVD.”

In an accompanying editorial, Professor Lawrence Appel from Johns Hopkins University commented: “The meta-analysis by Strazzullo and colleagues is a useful and welcome addition to the medical literature… The case for population-wide salt reduction is now stronger.”

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