title: Alanine aminotransferase/aspartate aminotransferase ratio is the best surrogate marker for insulin resistance in non-obese Japanese adults.
abstract: BACKGROUND
  The aim of the present study was to examine how liver markers are associated with insulin resistance in Japanese community-dwelling adults.
  
  
  METHODS
  This cross-sectional study included 587 men aged 58 ± 14 (mean ± standard deviation; range, 20-89) years and 755 women aged 60 ± 12 (range, 21-88) years. The study sample consisted of 998 (74.4%) non-obese [body mass index (BMI) <25.0 kg/m2] and 344 (25.6%) overweight (BMI ≥ 25 kg/m2) subjects. Insulin resistance was defined by homeostasis model assessment of insulin resistance (HOMA-IR) of at least 2.5, and HOMA-IR and potential confounders were compared between the groups. Areas under the curve (AUC) of the receiver operating characteristic curves (ROC) were used to compare the power of these serum markers.
  
  
  RESULTS
  In non-obese subjects, the best marker of insulin resistance was alanine aminotransferase (ALT)/aspartate aminotransferase (AST) ratio of 0.70 (95% confidence interval (CI), 0.63-0.77). In overweight subjects, AUC values for the ALT/AST ratio and ALT were 0.66 (0.59-0.72) and 0.66 (0.59-0.72), respectively. Multiple linear regression analyses for HOMA-IR showed that ALT/AST ratios were independently and significantly associated with HOMA-IR as well as other confounding factors in both non-obese and overweight subjects. The optimal cut-off point to identifying insulin resistance for these markers yielded the following values: ALT/AST ratio of ≥ 0.82 in non-obese subjects and ≥ 1.02 in overweight subjects. In non-obese subjects, the positive likelihood ratio was greatest for ALT/AST ratio.
  
  
  CONCLUSIONS
  In non-obese Japanese adults, ALT/AST ratio may be the best reliable marker of insulin resistance.
authors.affiliation: Department of Community Medicine, Ehime University Graduate School of Medicine, Toon-city, Ehime, Japan. rykawamo@m.ehime-u.ac.jp
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Kawamoto
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Kohara
authors.forename: Tomo
authors.initials: T
authors.lastname: Kusunoki
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Tabara
authors.forename: Masanori
authors.initials: M
authors.lastname: Abe
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Miki
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000410:Alanine Transaminase / Q000097:blood*; D019540:Area Under Curve; D044466:Asian People; D001219:Aspartate Aminotransferases / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D015992:Body Mass Index; D016009:Chi-Square Distribution; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007333:Insulin Resistance / Q000208:ethnology*; D007564:Japan; D016013:Likelihood Functions; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D012372:ROC Curve; D055815:Young Adult
chemical_list: D015415:Biomarkers; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase