A study published today on bmj.com reports that high salt intake is associated with considerably greater risk of both stroke and cardiovascular disease.

The link between high salt intake and high blood pressure is well-known. There is indication that a population-wide reduction in dietary salt intake has the potential to significantly reduce the levels of cardiovascular disease.

At the population level, the World Health Organization recommended level of salt consumption is 5 g, which is about one teaspoon per day. However in most Western countries, dietary salt intake is close to 10 g per day. It is much higher in many Eastern European countries.

Professor Pasquale Strazzullo at the University of Naples, Italy and Professor Francesco Cappuccio at the University of Warwick, UK, conducted collaborative research. They analyzed the results of thirteen published studies involving over 170,000 people. They directly assessed the relationship between levels of habitual salt intake and rates of stroke and cardiovascular disease.

Differences in study design and quality were considered to minimize bias.

Their investigation shows clearly that a difference of 5 g a day in habitual salt intake is associated with a 23 percent difference in the rate of stroke and a 17 percent difference in the rate of total cardiovascular disease.

Based on the evidence, the authors estimate that reducing daily salt intake by 5 g at the population level could prevent one and a quarter million deaths from stroke and almost three million deaths from cardiovascular disease each year. In addition, the authors say that because of ambiguity in measurement of salt intake, these effect sizes are likely to be underestimated.

They write in closing that these results support the role of a substantial population reduction in salt intake for the prevention of cardiovascular disease.

In an associated editorial, Professor Lawrence Appel from Johns Hopkins University says that this study is a helpful and welcome addition to the medical literature. It strengthens the case for population-wide salt reduction.

“Salt intake, stroke, and cardiovascular disease: meta-analysis of prospective studies”
Pasquale Strazzullo, professor of medicine, Lanfranco D’Elia, clinical lecturer in medicine, Ngianga-Bakwin, Kandala, principal research fellow in medical statistics, Francesco P Cappuccio, professor of cardiovascular medicine and epidemiology
BMJ 2009; 339:b4567

“The case for population-wide salt reduction gets stronger”
Lawrence J Appel

Written by Stephanie Brunner (B.A.)