Long term effects of dietary sodium reduction on cardiovascular disease outcomes: Observational follow-up of the trials of hypertension prevention (TOHP)

Nancy R. Cook, Jeffrey A. Cutler, Eva Obarzanek, Julie E. Buring, Kathryn M. Rexrode, Shiriki K. Kumanyika, Lawrence J. Appel, Paul K. Whelton

Research output: Contribution to journalArticle

Abstract

Objective: To examine the effects of reduction in dietary sodium intake on cardiovascular events using data from two completed randomised trials, TOHP I and TOHP II. Design: Longterm follow-up assessed 10-15 years after the original trial. Setting: 10 clinic sites in 1987-90 (TOHP I) and nine sites in 1990-5 (TOHP II). Central follow-up conducted by post and phone. Participants: Adults aged 30-54 years with prehypertension. Intervention: Dietary sodium reduction, including comprehensive education and counselling on reducing intake, for 18 months (TOHP I) or 36-48 months (TOHP II). Main outcome measure: Cardiovascular disease (myocardial infarction, stroke, coronary revascularisation, or cardiovascular death). Results: 744 participants in TOHP I and 2382 in TOHP II were randomised to a sodium reduction intervention or control. Net sodium reductions in the intervention groups were 44 mmol/24 h and 33 mmol/24 h, respectively. Vital status was obtained for all participants and follow-up information on morbidity was obtained from 2415 (77%), with 200 reporting a cardiovascular event. Risk of a cardiovascular event was 25% lower among those in the intervention group (relative risk 0.75, 95% confidence interval 0.57 to 0.99, P=0.04), adjusted for trial, clinic, age, race, and sex, and 30% lower after further adjustment for baseline sodium excretion and weight (0.70, 0.53 to 0.94), with similar results in each trial. In secondary analyses, 67 participants died (0.80, 0.51 to 1.26, P=0.34). Conclusion: Sodium reduction, previously shown to lower blood pressure, may also reduce long term risk of cardiovascular events.

Original languageEnglish (US)
Pages (from-to)885-888
Number of pages4
JournalBritish medical journal
Volume334
Issue number7599
DOIs
StatePublished - Apr 28 2007

ASJC Scopus subject areas

  • Medicine(all)

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