The risk for a cardiovascular event was lower among patients with borderline blood pressure who reduced sodium intake.
Reducing sodium intake has been demonstrated to lower blood pressure in people with hypertension and to prevent the onset of hypertension in people at risk for it. However, the effect of reducing sodium intake on cardiovascular disease outcomes and mortality remains somewhat controversial. This long-term follow-up study shows a beneficial effect on key outcomes.
U.S. investigators followed up participants in two randomized trials (TOHP I and II) that were completed in the 1990s. All 3126 participants had high normal blood pressure at baseline and were randomized to a sodium reduction intervention or a control group. Follow-up information was obtained from 2415 participants at 10 to 15 years after the original studies ended. The risk for a cardiovascular event was 25% lower in the intervention group, after adjustment for clinic, race, age, and sex. The risk for death from cardiovascular disease was 20% lower in the intervention group, but this difference did not quite reach statistical significance. Intervention patients were significantly more likely to prefer low-salt foods and to monitor their salt intake.
Comment: This study presents some of the strongest evidence yet to show that reducing sodium in the diet can reduce certain important clinical events, even in people without overt hypertension. The authors recommend less sodium for everyone as a public health measure, an approach endorsed in a recent review article on the role of sodium and potassium in the pathogenesis of hypertension (N Engl J Med 2007; 356:1966).
— Keith I. Marton, MD
Published in Journal Watch General Medicine May 8, 2007
Cook NR et al. Long term effects of dietary sodium reduction on cardiovascular disease outcomes: Observational follow-up of the trials of hypertension prevention (TOHP). BMJ 2007 Apr 28; 334:885.