Urinary epinephrine and norepinephrine interrelations with obesity, insulin, and the metabolic syndrome in Hong Kong Chinese

The metabolic syndrome is characterized by a clustering of cardiovascular r isk factors including type 2 diabetes mellitus, hypertension, dyslipidemia, and obesity. Elevated plasma insulin and urinary norepinephrine (noradrena line) and reduced urinary epinephrine (adrenaline) excretion are associated with obesity in Caucasian populations. We examined the interrelationships between obesity, plasma insulin, and urinary catecholamine excretion in Chi nese subjects with various components of the metabolic syndrome. A total of 577 Chinese subjects (aged 38 +/- 10 years; 68% with type 2 diabetes melli tus, hypertension, dyslipidemia, obesity, and/or albuminuria and 32% health y subjects) were studied, all of whom had a plasma creatinine less than 150 mu mol/L. The blood pressure, height, weight, waist and hip circumference, and fasting plasma glucose, insulin, lipid, and creatinine levels were mea sured. A 24-hour urine sample was collected for measurement of albumin and catecholamine excretion. The body mass index (BMI) and waist circumference were used as measures of general and central obesity, respectively. The ins ulin resistance index was estimated by the calculated product of fasting pl asma insulin and glucose concentrations. Patients with an increasing number of components of the metabolic syndrome (type 2 diabetes mellitus, hyperte nsion, dyslipidemia, obesity, and/or albuminuria) were more obese, hypergly cemic, dyslipidemic. and albuminuric and had higher blood pressure, plasma insulin, insulin resistance indices, and 24-hour urinary norepinephrine exc retion but lower urinary epinephrine output (all P < .005). Increasing quin tiles of BMI in the whole population or waist circumference in both sexes w ere associated with increasing trends for adverse lipid profiles, plasma in sulin, insulin resistance indices, and urinary norepinephrine excretion but a decreasing trend for urinary epinephrine output (all P < .001). There we re close associations between age, obesity, blood pressure, fasting plasma glucose, lipid, insulin, insulin resistance indices, and urinary catecholam ine excretion. Using stepwise multiple regression analysis (all P < .001), 34% of the variability of the BMI and 45% of that of the waist circumferenc e were independently related to gender (waist higher in males and BMI highe r in females), increased plasma insulin, triglyceride, and urinary norepine phrine excretion, and decreased high-density lipoprotein (HDL) cholesterol and urinary epinephrine output. In Chinese subjects with different manifest ations of the metabolic syndrome, hyperinsulinemia, insulin resistance, ele vated norepinephrine, and reduced epinephrine excretion were closely associ ated with general and central obesity. Based on these findings, we postulat e that complex interactions between the insulin and sympathoadrenal systems may lead to the development of obesity and the metabolic syndrome. Copyrig ht (C) 2007 by W.B. Saunders Company.