Relationship between urinary sodium and potassium, and arterial blood pressure: an epidemiologic study.

An epidemiologic study was conducted to ascertain the relationship between urinary sodium and potassium, and arterial blood pressure in normal, nonhospitalized adults. Random samples of 1,939 adult residents, 35 to 54 years of age, of Savannah, Georgia; Hagerstown, Maryland; and Pueblo, Colorado, were interviewed and examined. Arterial blood pressures were taken with a standardized zero-muddler in a standard fashion by a specially trained, experienced nurse. Casual urine specimens were collected and analyzed for their sodium and potassium content. The relationship between urinary sodium potassium and the sodium-to-potassium ratio and arterial blood pressure was calculated. Systolic and diastolic pressure increased with increasing levels of urinary sodium and the sodium-to-potassium ratio, and decreased with increasing levels of urinary potassium. The data suggest that dietary potassium provides some protection against the hypertensive effects of dietary sodium in humans as in animals.