The Levels of Serum Irisin as a Predictor of Insulin Resistance in Han Chinese Adults with Metabolically Healthy Obesity.

BACKGROUND: The aim of this study was to evaluate serum irisin levels and analyze its related factors in Han adults with metabolically healthy obesity. METHODS: This cross-sectional study included 75 metabolically healthy, non-obese adults and 51 metabolically healthy, obese adults. Anthropometric measurements, including height, weight, waist circumference (WC), and blood pressure, were performed. All patients underwent an oral glucose tolerance test (OGTT) after 8 hours of fasting, and the levels of glucose, insulin, lipids, and serum irisin were measured. RESULTS: The levels of serum irisin (5.40 ± 1.69 vs. 6.46 ± 1.37 µg/mL) were significantly lower in the metabolically healthy obese group (p < 0.05). Irisin correlated positively with high density lipoprotein cholesterol (HDL-C) (r = 0.303) and correlated negatively with body mass index (BMI) (r = -0.389), WC (r = -0.324), fasting plasma glucose (FPG) (r = -0.441), HOMA-IR (r = -0.429), triglycerides (TG) (r = -0.185), total cholesterol (TC) (r = -0.209), low density lipoprotein cholesterol (LDL-C) (r = -0.157) (p < 0.05). Multiple regression analysis revealed that FPG (ß = -1.720, p = 0.001) and HOMA-IR (ß = -0.399, p = 0.006) were still significantly associated with irisin. Serum irisin (ß = -0.246, p = 0.005) and BMI (ß = 0.078, p = 0.043) were significant independent predictors for HOMAIR. CONCLUSIONS: Serum irisin levels were reduced in metabolically healthy, obese Han adults. Irisin reduction appears to be associated with elevated FPG and insulin resistance but not obesity. In additional, falling irisin may increase the occurrence of insulin resistance in metabolically healthy Han adults and should be examined in future studies.