(HealthDay News) — The association between sodium intake and cardiovascular outcomes is complex, according to three studies published online in the August 14 issue of the New England Journal of Medicine.

Andrew Mente, PhD, from McMaster University in Hamilton, Canada, and colleagues examined the relationship between electrolyte excretion and blood pressure in 102,216 adults from 18 countries. The researchers found that for each 1g increment in estimated sodium excretion there were increments of 2.11mmHg and 0.78mmHg in systolic and diastolic blood pressure, respectively. Higher sodium intake correlated with a steeper slope for this association, as did hypertension and increased age.

Martin O’Donnell, PhD, also from McMaster University, and colleagues examined the estimated urinary sodium and potassium excretion and a composite outcome of death and major cardiovascular events for 101,945 individuals from 17 countries. The researchers found that an estimated sodium excretion higher than the reference range of 4.00–5.99g per day correlated with increased risk of the composite outcome (odds ratio, 1.15). Increased risk of the composite outcome was also seen for estimated sodium excretion <3.00g per day (odds ratio, 1.27). In a third modeling study, Dariush Mozaffarian, MD, DrPH, from Tufts University in Boston, and colleagues estimated that sodium consumption above a reference level of 2.0g per day contributed to 1.65 million deaths from cardiovascular causes that occurred in 2010.

“Taken together, these three articles highlight the need to collect high-quality evidence on both the risks and benefits of low-sodium diets,” write the authors of an accompanying editorial.

Several authors from the Mente study disclosed financial ties to the pharmaceutical industry. The Mente and O’Donnell studies were partially funded by grants from pharmaceutical companies.

Full Text – Mente
Full Text – O’Donnell
Full Text – Mozaffarian