title: The natural logarithm of zinc-α2-glycoprotein/HOMA-IR is a better predictor of insulin sensitivity than the product of triglycerides and glucose and the other lipid ratios.
abstract: OBJECTIVE
  The euglycemic-hyperinsulinemic clamp (EHC) is not available in most clinical settings and is costly, time consuming and invasive, and requires trained staff. Therefore, an accessible and inexpensive test to identify insulin resistance (IR) is needed. The aim of this study is to assess whether zinc-α2-glycoprotein (ZAG) index [Ln ZAG/homeostasis model assessment of IR (HOMA-IR)] is a better surrogate index for estimating IR or metabolic syndrome (MetS) compared with other surrogate indices.
  
  
  METHODS
  We performed a population-based cross-sectional study. Two hundred healthy subjects, 102 polycystic ovary syndrome (PCOS) patients, 97 newly diagnosed type 2 diabetes mellitus (nT2DM) and 84 impaired glucose tolerance (IGT) subjects were enrolled. The EHC was performed to identify IR. Circulating ZAG and adiponectin levels were determined by ELISA.
  
  
  RESULTS
  The ZAG index was significantly lower in participants with IR including IGT, nT2DM and PCOS than in those without IR. In addition, subjects with MetS had lower ZAG indices and higher the product of fasting triglycerides and glucose (TyG) indices than those without MetS. The ZAG index showed a significantly stronger association with M values than the other surrogate indices, whereas the TyG index showed a stronger association with MetS. The optimal cutoff value of the ZAG index for detection of IR was 2.97 with a sensitivity of 88% and a specificity of 91%, whereas the optimal cutoff value of TyG index for detection of MetS was 4.90 with a sensitivity of 82% and a specificity of 86%.
  
  
  CONCLUSIONS
  The ZAG index is a better marker than the other surrogate indices for identifying IR, whereas the TyG index has high sensitivity and specificity for identifying MetS.
authors.affiliation: Department of Endocrinology, Chongqing Red Cross Hospital (People's Hospital of Jiangbei District), Chongqing 400020, China.
authors.forename: Chunmei
authors.initials: C
authors.lastname: Qu
authors.affiliation: Department of Endocrinology, The Second Affiliated Hospital Chongqing Medical University, Chongqing 400010, China.
authors.forename: Xiaoxin
authors.initials: X
authors.lastname: Zhou
authors.affiliation: Department of Endocrinology, The Second Affiliated Hospital Chongqing Medical University, Chongqing 400010, China.
authors.forename: Gangyi
authors.initials: G
authors.lastname: Yang
authors.affiliation: Key Laboratory of Diagnostic Medicine (Ministry of Education) and Department of Clinical Biochemistry, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Pediatrics, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216-4505, USA.
authors.forename: Hua
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Endocrinology, Chongqing Red Cross Hospital (People's Hospital of Jiangbei District), Chongqing 400020, China. Electronic address: zerongliang@126.com.
authors.forename: Zerong
authors.initials: Z
authors.lastname: Liang
mesh_terms: D052242:Adiponectin / Q000097:blood; D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis*; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000175:diagnosis; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D018149:Glucose Intolerance / Q000097:blood* / Q000175:diagnosis; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood* / Q000175:diagnosis; D008875:Middle Aged; D011085:Polycystic Ovary Syndrome / Q000097:blood* / Q000175:diagnosis; D029589:Seminal Plasma Proteins / Q000097:blood*; D014280:Triglycerides / Q000097:blood*; D000090203:Zn-Alpha-2-Glycoprotein
chemical_list: D052242:Adiponectin; D001786:Blood Glucose; D029589:Seminal Plasma Proteins; D014280:Triglycerides; D000090203:Zn-Alpha-2-Glycoprotein
keywords: Insulin resistance; Metabolic syndrome; The product of triglycerides and glucose; Zinc-α2-glycoprotein