BACKGROUND: Adiponectin, an adipocytokine-mediating insulin action, has recently been found to be involved in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). The aim of this study was to assess possible associations between serum adiponectin levels and factors of the metabolic syndrome or histologic parameters in biopsy-proven NAFLD.METHODS: Patients with persistently abnormal liver function tests satisfying inclusion criteria were subjected to liver biopsy. Fibrosis stage and the NAFLD activity score were recorded for each patient. Body mass index, waist-to-hip ratio, factors of the metabolic syndrome (central obesity, hyperglycemia, hypertriglyceridemia, low high-density lipoprotein, and hypertension), and biochemical tests were also recorded. Insulin resistance was calculated by the homeostasis model assessment method. Serum adiponectin concentration was measured by an enzyme-linked immunosorbent assay.RESULTS: Forty-two NAFLD patients, including 9 with compensated cirrhosis, were included in the study. The presence of each factor of the metabolic syndrome was associated with hypoadiponectinemia. Adiponectin negatively correlated with homeostasis model assessment (r=-0.551, P=0.001). Adiponectin concentration was negatively associated with higher stages of fibrosis (one-wayanalysis of variance, P=0.007), and was not associated with NAFLD activity score. Using multivariate logistic regression, adiponectin concentration, aspartate aminotransferase/alanine aminotransferase ratio, and the presence of waist-to-hip ratio >1 were independent predictors of advanced fibrosis. The receiver operating characteristic curve for detecting advanced fibrosis using a combination of the independent variables had an area under the curve of 0.902+/-0.054, P<0.0001.CONCLUSIONS: Low serum adiponectin levels in NAFLD patients are suggestive of advanced fibrosis. Therefore, assessment of serum adiponectin levels may be useful in clinical follow-up.