Salt sensitivity correlates positively with insulin sensitivity in healthyvolunteers

Background The aim of the study was to assess the relationship between insu lin sensitivity and salt sensitivity in healthy subjects who display a wide range of insulin sensitivity. As a secondary objective, we assessed the re lationship between salt sensitivity and the other characteristics of the in sulin resistance syndrome. Study design Forty-seven normotensive volunteers (age 34 +/- 15 years) with a normal glucose tolerance test were selected. We measured insulin sensiti vity using the hyperinsulinaemic euglycaemic clamp (50 mUkg(-1)h(-1)), bloo d pressure, waist-to-hip ratio, fasting insulin levels, serum lipids and ur ic acid levels. In a subset of 21, representing a wide range of insulin sen sitivity, salt sensitivity was determined as the difference in mean arteria l blood pressure (MAP) at the end of a high-salt diet (10 g of NaCl per day for 1 week) vs. a low-salt diet (2 g of NaCl per day for 1 week). Results Insulin sensitivity (MII value, range 0.49-4.41 mgkg(-1)min(-1) per pmol L-1 x 100) was negatively correlated with MAP (r = -0.54, P < 0.001) and waist-to-hip ratio (r = -0.59, P < 0.001) but positively correlated wit h salt sensitivity (v = 0.47, P = 0.03). Salt sensitivity also correlated w ith high-density lipoprotein (HDL)-cholesterol (r = 0.46, P = 0.038) but no t with waist-to-hip ratio, fasting insulin levels, low-density lipoprotein cholesterol, serum triglycerides or serum uric acid. Conclusions In healthy normotensive subjects who display a wide range of in sulin sensitivity, as measured with the euglycaemic clamp technique, salt s ensitivity correlates positively with insulin sensitivity and HDL-cholester ol, but not with the other characteristics of the insulin resistance syndro me.