Salt and blood pressure: a community trial.

The effect of a health education programme on salt reduction and blood pressure was studied in two matched rural communities in Portugal, each of about 800 adult inhabitants. Initial salt intake was high (about 360 mmol/person/day) and 30% of persons were hypertensive (DBP 95 mmHg or above). In the intervention community average blood pressure fell by 3.6/5.0 mmHg at one year and 5.0/5.1 mmHg at two years, due to a general distribution shift. In the control community diastolic pressures remained stable and systolic pressures rose. The difference in trends between the two communities was highly significant. There were also significant correlations within individuals in the intervention community between fall in blood pressure and fall in urinary sodium/creatinine ratio. At least in this high-intake population a fall in salt consumption seems to have caused an important fall in average blood pressure.