Approximately 498 of 750 normal and hypertensive subjects who were carefully characterized in terms of blood pressure response to salt loading and depletion in the late 1970s were re-examined to identify physiological factors contributing to salt-sensitivity of blood pressure. This helped to confirm preliminary observations suggesting that salt sensitivity in normotensive subjects predicted the subsequent development of hypertension with aging. In addition, longitudinal observations in hypertensive patients and in normotensives helped to determine whether salt-sensitivity or salt-resistance of blood pressure were associated with differences in the risk for development of specific forms of cardiovascular disease (stroke, angina, myocardial infarction, congestive heart failure), renal and metabolic (diabetes mellitus) disorders.