Each participant provided three 24-hour urine collections, divided into daytime and overnight specimens for the assessment of sodium, potassium, creatinine, and water excretion. Four blood pressure measurements were made. Height and weight were measured. Information was collected on demographic variables, alcohol intake, history and treatment of blood pressure, medication use, family history of high blood pressure, cigarette use, and changes in dietary habits. Analysis of variance was the primary method of data analysis.