Salt sensitivity and insulin resistance: Is there a link?

Salt sensitivity is not only found in patients with essential hypertension but also in normotensive individuals. These salt-sensitive normotensives are believed to be genetically predisposed to the development of hypertension. In this paper we present data from our studies in such normotensive salt-sensitive individuals, thereby focusing on the relationship between salt sensitivity and familial history of hypertension and on insulin sensitivity. Salt-sensitivity was associated with a positive familial history of hypertension, a finding that supports the hypothesis that salt sensitivity in normotensive individuals points to a genetic predisposition for the development of hypertension. Also, salt-sensitive subjects displayed a hyperinsulinaemic response to an oral glucose load and a decreased insulin-mediated glucose disposal, as assessed by the insulin suppression test. The latter finding implies that insulin resistance is present in otherwise healthy, hypertension-prone individuals before overt hypertension develops. Assuming that there is a pathophysiological relationship between insulin resistance and salt sensitivity, our findings suggest that early recognition of insulin resistance and the implementation of measures aimed at improving insulin sensitivity could contribute to the prevention of cardiovascular disease in these individuals.