Insulin resistance is associated to future hypertension in normotensive salt-sensitive individuals: a 10-year follow-up study

Abstract

Background: Salt-sensitive hypertension is associated with insulin resistance in nonobese individuals. However, no data have been reported for normotensive offspring of hypertensive salt-sensitive parents.

Aims: To evaluate in normotensive salt-sensitive or salt-resistant offspring of hypertensive parents (offSS-HT and offSR-HT, respectively): the possible association between insulin resistance and endothelial dysfunction, and the risk of developing hypertension in a 10-year follow-up.

Design and methods: Forty-one offSS-HT (29 ± 2 years; 20 female) and 36 offSR-HT (25 ± 3 years; 16 female) were followed up for 10 years. Both groups were considered lean. At baseline, creatinine clearance (CrCl), 24 h urinary albumin excretion (UAE), glycemia, and insulinemia were measured before and after 60 and 120 min of glucose overload (75 g). HOMA Index and the area under the curve (AUC) were calculated. Blood pressure (BP) and 24 h urine sodium excretion was measured annually. Postischemic minimum vascular resistance (forearm plethysmography) was assessed at baseline.

Results: In offSS-HT, UAE (53 ± 3 mg/min) and CrCl (136 ± 8 ml/min) were higher in offSS-HT than in offSR-HT. (UAE: 12 ± 4 mg.min; p,0.01 and CrCl 107 ± 6 ml.min; P < 0.01). An impaired vasodilatory postischemic response was observed in offSS-HT compared with offSR-HT ( P < 0.01). In offSS-HT glycemia, insulin, AUC at 69 and 120 min post OTG were greater than in offSR-HT, p < 0.02. In offSS-HT, blood pressure rose ( P < 0.01) the 10 years follow-up compared with offSR-HT.

Conclusion: Salt sensitivity in the offspring of hypertensive salt-sensitive individuals is associated with insulin resistance and endothelial dysfunction and is prone to hypertension over a short period of time.