Association of Serum Irisin with Metabolic Syndrome in Obese Chinese Adults

Abstract

Irisin, a recently identified novel myokine, drives brown-fat-like conversion of white adipose tissues and has been proposed to mediate beneficial effects of exercise on metabolism. Circulating irisin was significantly reduced in type 2 diabetes patients; however, no evidence is available about its association with metabolic syndrome (MetS) and effects of adiposity and muscle mass on circulating irisin have been controversial. Cross-sectional data on socio-demographic, lifestyle, clinical characteristics and serum irisin were collected for 1,115 community-living Chinese adults with central obesity. Associations of serum irisin with MetS (central obesity plus any two of the following four factors (raised blood pressure (BP), raised fasting plasma glucose (FPG), raised triglyceride (TG), and reduced HDL cholesterol) and each component of MetS were analyzed using multivariable logistic regression. Among the 1,115 obese Chinese adults with a mean age of 53.2(±7.2) years, serum irisin levels (log-transformed) were significantly reduced in subjects with MetS and raised FPG than their control groups (p = 0.034 and 0.041, respectively). After adjustment for potential confounders, serum irisin was significantly associated with reduced risks of MetS and raised FPG, with odds ratios (ORs) (95% CI) per standard deviation of log-transformed irisin of 0.796 (0.505–0.959, p = 0.027) and 0.873 (0.764–0.998, p = 0.046), respectively. Associations of irisin with raised BP, raised TG and reduced HDL were not statistically significant ((ORs) (95% CI): 0.733(0.454–1.182, p = 0.202), 0.954(0.838–1.086, p = 0.478) and 1.130(0.980–1.302, p = 0.092), respectively). Stepwise multivariable linear regression analysis showed that fasting insulin, HbA1c and albumin/globulin ratio were negatively associated with serum irisin level with statistical significance (all p-values <0.05) and waist circumference was negatively associated with serum risin with marginally statistical significance (p = 0.055). These results imply that irisin may play an important role in insulin resistance and MetS and should be confirmed in future prospective studies.

Relationship between serum irisin levels and urinary albumin excretion in patients with type 2 diabetes

“…It is conceivable that this association has a direct and/or indirect effect on the endothelial dysfunction in patients with type 2 diabetes. Besides, it has been suggested that waist circumference, fast insulin, FBG and 2-h BG, are related to serum irisin levels (Yan et al, 2014). Our findings indicate similar results.…”

Factors associated with increased irisin levels in the type 1 diabetes mellitus

“…We did not found any study examining the relation between irisin and HbA1c in T1DM patients. However, in studies conducted with patients with the T2DM and metabolic syndromein contrast with our study -irisin levels were negatively correlated with HbA1c (Choi et al 2013;Yan et al 2014). Th is relation between irisin and HbA1c have not been interpreted in these studies.…”

An update on the validity of irisin assays and the link between irisin and hepatic metabolism

“…Notably, within NAFLD group, those with mild steatosis had higher irisin levels than NAFLD patients with moderate-to-severe steatosis. It is also of interest that similar irisin levels were observed between obese in non-obese individuals, or between individuals with and without metabolic syndrome in this study [31], contrary to other studies showing increased [32] or decreased [33] irisin levels in individuals with metabolic syndrome. Choi et al speculated that irisin increases in early steatosis, as a compensatory mechanism to limit it, but if the mechanism fails and steatosis progresses, irisin decreases [31].…”