Objective: To test the short-term feasibility and efficacy of seven nonpharmacologic interventions in persons with high normal diastolic blood pressure.
Design: Randomized control multicenter trials.
Setting: Volunteers recruited from the community, treated and followed up at special clinics.
Participants: Of 16,821 screenees, 2182 men and women, aged 30 through 54 years, with diastolic blood pressure from 80 through 89 mm Hg were selected. Of these, 50 did not return for follow-up blood pressure measurements.
Interventions: Three life-style change groups (weight reduction, sodium reduction, and stress management) were each compared with unmasked nonintervention controls over 18 months. Four nutritional supplement groups (calcium, magnesium, potassium, and fish oil) were each compared singly, in double-blind fashion, with placebo controls over 6 months.
Main outcome measures: Primary: change in diastolic blood pressure from baseline to final follow-up, measured by blinded observers. Secondary: changes in systolic blood pressure and intervention compliance measures.
Results: Weight reduction intervention produced weight loss of 3.9 kg (P less than .01), diastolic blood pressure change of -2.3 mm Hg (P less than .01), and systolic blood pressure change of -2.9 mm Hg (P less than .01). Sodium reduction interventions lowered urinary sodium excretion by 44 mmol/24 h (P less than .01), diastolic blood pressure by 0.9 mm Hg (P less than .05), and systolic blood pressure by 1.7 mm Hg (P less than .01). Despite good compliance, neither stress management nor nutritional supplements reduced diastolic blood pressure or systolic blood pressure significantly (P greater than .05).
Conclusions: Weight reduction is the most effective of the strategies tested for reducing blood pressure in normotensive persons. Sodium reduction is also effective. The long-term effects of weight reduction and sodium reduction, alone and in combination, require further evaluation.