Role of salt sensitivity, blood pressure, and hyperinsulinemia in determining high upper normal levels of urinary albumin excretion in a healthy adult population

Background The objective of this study was to investigate the role of blood pressure (BP), salt sensitivity (SS), and the cardiovascular metabolic syndrome in determining the urinary albumin excretion (UAE) in glucose-tolerant, normoalbuminuric (<20 mg/day) healthy adults. Methods and results We evaluated 177 healthy subjects (age, 38.3 ± 0.9 years; weight, 75.2 ± 1.1 kg; body mass index, 28.8 ± 0.4 kg/m2; systolic BP, 117 ± 1 mm Hg; diastolic BP, 77.5 ± 0.8 mm Hg; UAE, 8.2 ± 0.3 mg/24 h). Subjects with UAE levels of 15 to 20 mg/day had higher systolic BP, diastolic BP, and pulse pressures than those with UAE levels less than 15 mg/day (P< .0001). Hypertension (HT) and SS were more prevalent in the high normal UAE group (15 to 20 mg/day) than in groups with lower UAE (47% v 8% for HT and 67% v 24% for SS). In normotensives (n = 156), no differences in BP were observed among the different UAE strata; yet, the prevalence of SS was greater in the high (57%) compared to the low normal (17% to 21%) UAE groups. Similar levels of UAE, BP, and similar prevalence of SS were found in men with and without abdominal obesity, despite the fact that obesity was associated with hypertriglyceridemia and hyperinsulinemia. Conclusions In healthy normoalbuminuric adults, high normal UAE is associated with SS in normotensives and with SS and higher BP in a mixed population (88% normotensive and 12% hypertensive). Abdominal obesity, hypertriglyceridemia, and hyperinsulinemia were not related to UAE. Therefore, UAE levels of 15 to 20 mg/day should be accepted as microalbuminuria, and these subjects may benefit from early intervention (ie, salt restriction and BP lowering).