title: Urine Albumin-to-Creatinine Ratio: A Marker of Early Endothelial Dysfunction in Youth.
abstract: BACKGROUND
  The urine albumin-to-creatinine ratio (UACR) is a useful predictor of cardiovascular (CV) events in adults. Its relationship to vascular function in children is not clear.
  
  
  OBJECTIVE
  We investigated whether UACR was related to insulin resistance and endothelial function, a marker of subclinical atherosclerosis, in adolescents across the spectrum of glucose regulation.
  
  
  METHODS
  Participants were 58 adolescents: 13 normal weight (NW), 25 overweight with normal glucose tolerance (OW-NGT), and 20 overweight with prediabetes (OW-PreD).
  
  
  METHODS
  Interventions included oral glucose tolerance test, hyperinsulinemic-euglycemic clamp with determination of insulin sensitivity (IS), endothelial function assessment by peripheral arterial tonometry determination of the reactive hyperemia index (RHI), body composition (dual-energy x-ray absorptiometry), and abdominal fat distribution (magnetic resonance imaging).
  
  
  METHODS
  Fasting UACR was determined.
  
  
  RESULTS
  The 3 groups did not differ with respect to age, sex, or Tanner stage. The NW group had significantly lower percent body fat, higher IS (10.4 ± 0.9, 3.5 ± 0.6, and 2.1 ± 0.2 mg/kg/min per μU/mL; P < .001), and higher RHI (1.84 ± 0.1, 1.56 ± 0.1, and 1.56 ± 0.1, P = .04) than the OW-NGT and OW-PreD groups, respectively. lnUACR was related to percent body fat (r = 0.4, P = .001), RHI (r = -0.33, p = .01), and IS (r = -0.27, P = .043). In multiple regression analysis with lnUACR as the dependent variable and RHI, percent body fat, age, sex, race, systolic blood pressure, cholesterol, glycated hemoglobin, and IS as independent variables, RHI (β = -0.3, P = .045) and sex (β = 0.31, P = .06) contributed to the variance in UACR (R(2) = 0.35, P = .02).
  
  
  CONCLUSIONS
  UACR is an early marker of endothelial dysfunction in youth, independent of glycemia. Endothelial dysfunction may mediate the link between obesity-related insulin resistance and early microalbuminuria.
authors.affiliation: Children's Nutrition Research Center (S.K.B., M.C.C., A.T., F.B.), Baylor College of Medicine, Houston, Texas 77030; and Division of Pediatric Diabetes and Endocrinology (S.K.B., M.C.C., A.T., F.B.) and Department of Radiology, (R.K.), Texas Children's Hospital, Houston, Texas 77030.
authors.forename: Sara Klinepeter
authors.initials: SK
authors.lastname: Bartz
authors.affiliation: Children's Nutrition Research Center (S.K.B., M.C.C., A.T., F.B.), Baylor College of Medicine, Houston, Texas 77030; and Division of Pediatric Diabetes and Endocrinology (S.K.B., M.C.C., A.T., F.B.) and Department of Radiology, (R.K.), Texas Children's Hospital, Houston, Texas 77030.
authors.forename: Maria C
authors.initials: MC
authors.lastname: Caldas
authors.affiliation: Children's Nutrition Research Center (S.K.B., M.C.C., A.T., F.B.), Baylor College of Medicine, Houston, Texas 77030; and Division of Pediatric Diabetes and Endocrinology (S.K.B., M.C.C., A.T., F.B.) and Department of Radiology, (R.K.), Texas Children's Hospital, Houston, Texas 77030.
authors.forename: Anca
authors.initials: A
authors.lastname: Tomsa
authors.affiliation: Children's Nutrition Research Center (S.K.B., M.C.C., A.T., F.B.), Baylor College of Medicine, Houston, Texas 77030; and Division of Pediatric Diabetes and Endocrinology (S.K.B., M.C.C., A.T., F.B.) and Department of Radiology, (R.K.), Texas Children's Hospital, Houston, Texas 77030.
authors.forename: Ramkumar
authors.initials: R
authors.lastname: Krishnamurthy
authors.affiliation: Children's Nutrition Research Center (S.K.B., M.C.C., A.T., F.B.), Baylor College of Medicine, Houston, Texas 77030; and Division of Pediatric Diabetes and Endocrinology (S.K.B., M.C.C., A.T., F.B.) and Department of Radiology, (R.K.), Texas Children's Hospital, Houston, Texas 77030.
authors.forename: Fida
authors.initials: F
authors.lastname: Bacha
mesh_terms: D000293:Adolescent; D000418:Albumins; D000419:Albuminuria / Q000652:urine*; D050197:Atherosclerosis / Q000175:diagnosis* / Q000503:physiopathology / Q000652:urine; D015415:Biomarkers / Q000652:urine; D002648:Child; D003404:Creatinine / Q000652:urine*; D004730:Endothelium, Vascular / Q000503:physiopathology*; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology; D008297:Male; D050177:Overweight / Q000503:physiopathology / Q000652:urine*; D011236:Prediabetic State / Q000503:physiopathology / Q000652:urine*
chemical_list: D000418:Albumins; D015415:Biomarkers; D003404:Creatinine