Salt and blood pressure in Rio Grande do Sul, Brazil.

A 1978 survey of 4,565 people in Rio Grande do Sul obtained interview and blood pressure data as well as casual urine specimens for subsequent sodium and creatinine titrations. Data derived from this survey have demonstrated a variety of complex relationships between blood pressure and sodium, a number of which are examined here. The main conclusion is that observed blood pressure differentials could reflect the kidney's ability to handle sodium, an ability subject to the influences of age, heredity, and the environment. As a consequence, it is suggested that the adoption of salt restriction by populations could bring them large health benefits.