title: comparative study of glucose homeostasis, lipids and lipoproteins, HDL functionality, and cardiometabolic parameters in modestly severely obese African Americans and White Americans with prediabetes: implications for the metabolic paradoxes.
abstract: OBJECTIVE
  To determine whether modestly severe obesity modifies glucose homeostasis, levels of cardiometabolic markers, and HDL function in African Americans (AAs) and white Americans (WAs) with prediabetes.
  
  
  METHODS
  We studied 145 subjects with prediabetes (N = 61 WAs, N = 84 AAs, mean age 46.5 ± 11.2 years, mean BMI 37.8 ± 6.3 kg/m(2)). We measured fasting levels of lipids, lipoproteins, and an inflammatory marker (C-reactive protein [CRP]); HDL functionality (i.e., levels of paraoxonase 1 [PON1]); and levels of oxidized LDL, adiponectin, and interleukin-6 (IL-6). We measured serum levels of glucose, insulin, and C-peptide during an oral glucose tolerance test. Values for insulin sensitivity index (Si), glucose effectiveness index (Sg), glucose effectiveness at zero insulin (GEZI), and acute insulin response to glucose (AIRg) were derived using a frequently sampled intravenous glucose tolerance test (using MINMOD software).
  
  
  RESULTS
  Mean levels of fasting and incremental serum glucose, insulin, and C-peptide tended to be higher in WAs versus AAs. The mean Si was not different in WAs versus AAs (2.6 ± 2.3 vs. 2.9 ± 3.0 × 10(-4) × min(-1) [μU/mL](-1)). Mean values for AIRg and disposition index as well as Sg and GEZI were lower in WAs than AAs. WAs had higher serum triglyceride levels than AAs (116.1 ± 55.5 vs. 82.7 ± 44.2 mg/dL, P = 0.0002). Mean levels of apolipoprotein (apo) A1, HDL cholesterol, PON1, oxidized LDL, CRP, adiponectin, and IL-6 were not significantly different in obese AAs versus WAs with prediabetes.
  
  
  CONCLUSIONS
  Modestly severe obesity attenuated the ethnic differences in Si, but not in Sg and triglyceride levels in WAs and AAs with prediabetes. Despite the lower Si and PON1 values, AAs preserved paradoxical relationships between the Si and HDL/apoA1/triglyceride ratios. We conclude that modestly severe obesity has differential effects on the pathogenic mechanisms underlying glucose homeostasis and atherogenesis in obese AAs and WAs with prediabetes.
authors.affiliation: Division of Endocrinology, Diabetes and Metabolism, Wexner Medical Center, The Ohio State University, Columbus, OH.
authors.forename: Sara J
authors.initials: SJ
authors.lastname: Healy
authors.affiliation: Division of Endocrinology, Diabetes and Metabolism, Wexner Medical Center, The Ohio State University, Columbus, OH.
authors.forename: Kwame
authors.initials: K
authors.lastname: Osei
authors.affiliation: College of Nursing, University of Cincinnati, Cincinnati, OH trudy.gaillard@uc.edu.
authors.forename: Trudy
authors.initials: T
authors.lastname: Gaillard
mesh_terms: D052242:Adiponectin / Q000378:metabolism; D000328:Adult; D001741:Black or African American / Q000208:ethnology*; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism*; D002096:C-Peptide / Q000378:metabolism; D002097:C-Reactive Protein / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000208:ethnology* / Q000378:metabolism; D005215:Fasting / Q000097:blood; D005260:Female; D005951:Glucose Tolerance Test; D006706:Homeostasis / Q000502:physiology; D006801:Humans; D007328:Insulin / Q000378:metabolism; D007333:Insulin Resistance / Q000502:physiology; D015850:Interleukin-6 / Q000378:metabolism; D050356:Lipid Metabolism / Q000502:physiology; D008074:Lipoproteins / Q000097:blood; D008075:Lipoproteins, HDL / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000208:ethnology* / Q000378:metabolism; D011236:Prediabetic State / Q000208:ethnology* / Q000378:metabolism; D014280:Triglycerides / Q000378:metabolism; D014481:United States; D044465:White People / Q000208:ethnology*; D055815:Young Adult
chemical_list: D052242:Adiponectin; D001786:Blood Glucose; D002096:C-Peptide; C034396:HDL-triglyceride; D007328:Insulin; D015850:Interleukin-6; D008074:Lipoproteins; D008075:Lipoproteins, HDL; D014280:Triglycerides; D002097:C-Reactive Protein