Background: Irisin is a myokine that leads to increased energy expenditure by stimulating the browning of white adipose tissue. We aimed to investigate the association of serum irisin levels with metabolic parameters in middle aged Chinese population.
Methods: The study was based on a cross-sectional analysis of data from 524 nondiabetic subjects aged 40~65. All participants were recruited from a screening survey for Metabolic Syndrome in a community in Southwest China, including 294 subjects categorized as overweight (defined as BMI≧25 kg/m2) and 230 subjects as normal control (defined as 18.5≦BMI < 25 kg/m2). Serum irisin concentration was quantified by enzyme linked immunosorbent assay (ELISA). The relationship of irisin with metabolic factors was determined by Pearson correlation. Multivariate linear regression was used to analyze the association of irisin with insulin resistance. Logistic regression was performed to assess the association of irisin with odds of overweight.
Results: Serum irisin levels were significantly lower in nondiabetic overweight subjects compared with control (11.46 ± 4.11vs14.78 ± 7.03 μg/mL, p = 0.02). Circulating irisin was positively correlated with quantitative insulin sensitivity check index (QUICKI, r = 0.178, p = 0.045) and triglycerides (r = 0.149, p = 0.022); while irisin was negatively correlated with waist circumference (WC, r = - 0.185, p = 0.037), waist-to-hip ratio (WHR, r = - 0.176, p = 0.047), fasting insulin (r = - 0.2, p = 0.024), serum creatinine (r = - 0.243, p = 0.006), homeostasis model assessment for insulin resistance (HOMA-IR, r = - 0.189, p = 0.033). Multiple linear regression showed that irisin was inversely associated with HOMA-IR (β = - 0.342 ± 0.154, p = 0.029). Higher irisin was associated with decreased odds of being overweight (OR = 0.281, β = - 1.271, p = 0.024).
Conclusions: We found that serum irisin levels were lower in overweight subjects. Moreover, serum irisin levels were inversely correlated with adverse metabolic parameters including WC, WHR, creatinine, HOMA-IR and fasting insulin, suggesting that irisin may play a role in obesity related insulin resistance.
Keywords: Insulin resistance; Irisin; Myokines; Obesity.