Salt sensitivity is associated with an increased mortality in both normal and hypertensive humans

While a variety of studies have demonstrated the heterogeneity of the blood pressure response to salt loading and depletion, none has examined the relationship of these responses to mortality. We conducted a follow-up study of 430 normal and 278 hypertensive subjects studied as long ago as 28 years by techniques to assess their blood pressure responses to salt and volume expansion and depletion (salt sensitivity). We found that 123 (21%) of our study subjects had died in the interval since the initial study. The following measures were found to be significantly associated with the risk for death: blood pressure (systolic, diastolic, mean arterial, and pulse pressures), hypertension, age, salt sensitivity, baseline renin levels (inverse), and body mass index (but not body weight). Normotensive, salt-sensitive subjects had a survival that was no different than that of hypertensive subjects. Only initially normotensive, salt-resistant individuals had improved survival. Studies are continuing in order to elucidate the mechanisms by which salt sensitivity, even in normotensive subjects, may lead to reduced survival.