Study Questions Mortality Benefits of Reduced Sodium Intake

The effects of reduced sodium intake on mortality risk are nonsignificant compared with average sodium intake, according to a new study.

High sodium intake has been linked with increased mortality. However, the effects of reduced sodium intake are still controversial.
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The researchers examined 2 studies conducted during the Trials of Hypertension Prevention, which implemented sodium reduction interventions among adults aged 30 to 54 years with prehypertension.

Phase I included 744 participants who were randomly assigned to sodium reduction or usual intake over 18 months (1987-1990). Phase II included 2382 participants who were randomly assigned to the same groups over 36 months (1990-1995).

The researchers collected multiple 24-hour urine samples from participants and attained post-trial death rates via the National Death Index.

After a median 24-year follow-up, 251 deaths occurred in the reduced sodium group, and 272 deaths occurred in the usual sodium intake group—a nonsignificant 15% lower risk with intervention.

For the usual sodium intake group, mortality risk was 12% higher for every 1000 mg/24 h increase in sodium excretion. Very low sodium intake was not associated with mortality risk.

“We found an increased risk of mortality for high-sodium intake and a direct relationship with total mortality, even at the lowest levels of sodium intake,” the researchers concluded. “These results are consistent with a benefit of reduced sodium and sodium/potassium intake on total mortality over a 20-year period.”

—Amanda Balbi

Reference:

Cook NR, Appel LJ, Whelton PK. Sodium intake and all-cause mortality over 20 years in the Trials of Hypertension Prevention. J Am Coll Cardiol. 2016;68(15):1609-1617. doi:10.1016/j.jacc.2016.07.745.