Relationship between urinary albumin excretion, body composition, and hyperinsulinemia in normotensive glucose-tolerant adults

OBJECTIVE - Elevated urinary albumin excretion (UAE) has been associated wi th insulin resistance and is suggested to be elevated in prediabetic indivi duals. Upper body obesity especially visceral obesity predicts insulin resi stance and development of type 2 diabetes. We examined whether UAE clusters with obesity-associated insulin resistance traits in healthy glucose-toler ant normotensive subjects. RESEARCH DESIGN AND METHODS - There were 49 volunteers with a wide range of body fat and body fat distribution studied. All had normal blood pressure and glucose tolerance and were maintained on a controlled diet for 2 weeks. UAE was assessed from three overnight urine collections, and body composit ion was assessed by whole-body dual-energy X-ray absorptiometry scanning an d abdominal computed tomography scanning. RESULTS- Fasting insulin and insulin responses to oral glucose were signifi cantly increased in obese subjects, who also tended to have more dyslipidem ia, greater blood pressure, and more visceral fat than lean subjects. These differences were more apparent in upper body obese subjects. UAE was norma l in obese and upper body obese subjects and not different from that of lea n subjects. UAE ranged from 0.3 to 8.3 mu g/min in lean subjects and from 0 .2 to 7.2 mu g/min in obese subjects. UAE was not significantly correlated with body composition, plasma insulin, glucose, or lipids. CONCLUSIONS - Obese subjects (even upper body obese subjects) with increase d visceral and total body fat, high plasma insulin and triglycerides, and l ow HDL cholesterol concentrations do not have elevated UAE. This suggests t hat UAE is not closely associated with these characteristics and implies a later onset of abnormal albuminuria in the course of the insulin resistance syndrome.