Serum Adipocyte Fatty Acid-binding Protein Levels: An Indicator of Non-alcoholic Fatty Liver Disease in Chinese Individuals

Background & Aims: Serum adipocyte fatty acid-binding protein (A-FABP) is closely correlated to metabolic disorders such as obesity and insulin resistance (IR). Non-alcoholic fatty liver disease (NAFLD) is a typical feature of IR in the liver. The aim of this study was to explore the relationship between serum A-FABP levels and NAFLD.

Methods: The study enrolled 728 subjects with normal glucose tolerance from communities. Serum A-FABP levels were measured using a sandwich enzyme-linked immunosorbent assay. The liver fat content was assessed by ultrasonography. The fatty liver index (FLI) was calculated to quantify the degree of liver steatosis. The upper quartile of homoeostasis model assessment-insulin resistance (HOMA-IR) in the total population was defined as IR. Adipose tissue insulin resistance (Adipo-IR) was calculated to evaluate the impaired suppression of lipolysis in IR.

Results: Serum A-FABP levels were significantly higher in subjects with NAFLD than in those without (P < 0.01). Moreover, subjects with IR had higher levels of A-FABP than those without (P < 0.01). The proportion of IR or NAFLD and the levels of fasting free fatty acid (FFA) or Adipo-IR displayed an upward trend as A-FABP increased (P for trend < 0.05). After adjusting for gender, age, body fat, metabolic factors and liver enzymes, A-FABP was independently correlated with NAFLD (P < 0.01). A-FABP was a positive determinant of FLI (P = 0.006).

Conclusions: Serum A-FABP levels were significantly elevated in NAFLD patients among a population with normal glucose tolerance. Serum A-FABP levels were independently correlated with NAFLD after adjusting for confounding factors.