Meta-Analysis Reaffirms Salt's Link with Cardiovascular Disease

These Italian authors examined the relation between the level magnitude of dietary salt intake and stroke or cardiovascular disease. They performed a systematic review and meta-analysis of prospective studies published 1966-2008. For each study, relative risks and 95% confidence intervals were extracted and then pooled with a random effect model. Heterogeneity, publication bias, subgroup, and meta-regression analyses were performed.

They found: "There were 19 independent cohort samples from 13 studies, with 177,025 participants (follow-up 3.5-19 years) and over 11,000 vascular events. Higher salt intake was associated with greater risk of stroke (pooled relative risk 1.23) and cardiovascular disease (1.14), with no significant evidence of publication bias. For cardiovascular disease, sensitivity analysis showed that the exclusion of a single study led to a pooled estimate of 1.17 (1.02 to 1.34). The associations observed were greater the larger the difference in sodium intake and the longer the follow-up."

The authors concluded: "High salt intake is associated with significantly increased risk of stroke and total cardiovascular disease. Because of imprecision in measurement of salt intake, these effect sizes are likely to be underestimated. These results support the role of a substantial population reduction in salt intake for the prevention of cardiovascular disease."

This large meta-analysis provides further evidence of the importance of salt in cardiovascular disease, including stroke. The authors make the case that the salt intake should be addressed at the population level, not just at the individual level.

British Medical Journal 334:859-860; 24 November 2009. © 2009 to BMJ Publishing
Salt intake, stroke, and cardiovascular disease: meta-analysis of prospective studies. Pasquale Strazzullo, Lanfranco D'Elia, Ngianga-Bakwin Kandala, Francesco P Cappuccio.