Dietary sodium and mortality: how much do we really know?

This editorial refers to ‘Sodium intake, life expectancy, and all-cause mortality’†, by F. Messerli et al., on page 2103. Messerli et al. conducted a detailed examination of the association of sodium intake and mortality, and found an inverse association with mortality, as reported in this issue of the European Heart Journal.1 The authors’ conclusions are that such a finding should call into question the present understanding that higher sodium intake is associated with higher risk for mortality. We applaud the authors on taking on the immense task of evaluating the relationship between sodium consumption and mortality on a global scale. While the effort is laudable, there are several aspects about the study design and analysis that must be carefully considered when reviewing the findings of this article. (i) Ecological fallacy is a major concern when interpreting aggregate or country-level data. Ecological studies are...