title: Elevated circulating irisin is associated with lower risk of insulin resistance: association and path analyses of obese Chinese adults.
abstract: BACKGROUND
  Evidence on the role of irisin in insulin resistance is limited and controversial, and pathways between them remain unknown. We aimed to examine the independent effects of circulating irisin and different adiposity measurements, as well as their potential interactions, on insulin resistance. We also aimed to explore possible pathways among circulating irisin, adiposity, glucose and insulin levels and insulin resistance.
  
  
  METHODS
  A cross-sectional study of 1,115 community- living obese Chinese adults, with data collection on clinical characteristics, glucose and lipid metabolic parameters and circulating irisin levels.
  
  
  RESULTS
  Among the 1,115 subjects, 667 (59.8 %) were identified as insulin-resistance, and showed significantly decreased serum irisin than their controls (log-transformed irisin: 1.19 ± 2.34 v.s. 1.46 ± 2.05 ng/ml, p = 0.042). With adjustment for potential confounders, elevated circulating irisin was significantly associated with reduced risk of insulin resistance, with adjusted odds ratio per standard deviation increase of irisin of 0.871 (0.765-0.991, p = 0.036). As for different adiposity measurements, body fat percentage, but neither BMI nor waist, was significantly associated with increased risk of insulin resistance (OR: 1.152 (1.041-1.275), p = 0.006). No significant interaction effect between serum irisin and adiposity on insulin resistance was found. A one pathway model about the relationship between serum irisin and insulin resistance fits well (χ (2) = 44.09, p < 0.001; CFI-0.994; TLI =0.986; and RMSEA = 0.067), and shows that elevated circulating irisin might improve insulin resistance indirectly through lowering fasting insulin levels (standardized path coefficient = -0.046, p = 0.032).
  
  
  CONCLUSIONS
  Elevated circulating irisin is associated with lower risk of insulin resistance indirectly through lowering fasting insulin.
authors.affiliation: Department of Endocrinology and Diabetes, The First Affiliated Hospital, Xiamen University, 55# Zhenhai Road, Xaimen, 361003, China.
authors.forename: Xiulin
authors.initials: X
authors.lastname: Shi
authors.affiliation: Department of Endocrinology and Diabetes, The First Affiliated Hospital, Xiamen University, 55# Zhenhai Road, Xaimen, 361003, China.
authors.forename: Mingzhu
authors.initials: M
authors.lastname: Lin
authors.affiliation: Department of Endocrinology and Diabetes, The First Affiliated Hospital, Xiamen University, 55# Zhenhai Road, Xaimen, 361003, China.
authors.forename: Changqin
authors.initials: C
authors.lastname: Liu
authors.affiliation: Department of Endocrinology and Diabetes, The First Affiliated Hospital, Xiamen University, 55# Zhenhai Road, Xaimen, 361003, China.
authors.forename: Fangsen
authors.initials: F
authors.lastname: Xiao
authors.affiliation: Department of Endocrinology and Diabetes, The First Affiliated Hospital, Xiamen University, 55# Zhenhai Road, Xaimen, 361003, China.|Department of Nursing, The First Affiliated Hospital, Xiamen University, Xiamen, China.
authors.forename: Yongwen
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Endocrinology and Diabetes, The First Affiliated Hospital, Xiamen University, 55# Zhenhai Road, Xaimen, 361003, China.
authors.forename: Peiying
authors.initials: P
authors.lastname: Huang
authors.affiliation: Department of Endocrinology and Diabetes, The First Affiliated Hospital, Xiamen University, 55# Zhenhai Road, Xaimen, 361003, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Zeng
authors.affiliation: Xiamen Diabetes Institute, The First Affiliated Hospital, Xiamen University, No. 55 Zhenhai Road, Xaimen, 361003, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Yan
authors.affiliation: Xiamen Diabetes Institute, The First Affiliated Hospital, Xiamen University, No. 55 Zhenhai Road, Xaimen, 361003, China.
authors.forename: Suhuan
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Endocrinology and Diabetes, The First Affiliated Hospital, Xiamen University, 55# Zhenhai Road, Xaimen, 361003, China.|Xiamen Diabetes Institute, The First Affiliated Hospital, Xiamen University, No. 55 Zhenhai Road, Xaimen, 361003, China.|Department of Endocrinology, Zhongshan Hospital, Fudan University, Shanghai, China.
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Endocrinology and Diabetes, The First Affiliated Hospital, Xiamen University, 55# Zhenhai Road, Xaimen, 361003, China.|Xiamen Diabetes Institute, The First Affiliated Hospital, Xiamen University, No. 55 Zhenhai Road, Xaimen, 361003, China.
authors.forename: Shuyu
authors.initials: S
authors.lastname: Yang
authors.affiliation: Department of Endocrinology and Diabetes, The First Affiliated Hospital, Xiamen University, 55# Zhenhai Road, Xaimen, 361003, China. xmlixuejun@163.com.|Xiamen Diabetes Institute, The First Affiliated Hospital, Xiamen University, No. 55 Zhenhai Road, Xaimen, 361003, China. xmlixuejun@163.com.
authors.forename: Xuejun
authors.initials: X
authors.lastname: Li
authors.affiliation: Xiamen Diabetes Institute, The First Affiliated Hospital, Xiamen University, No. 55 Zhenhai Road, Xaimen, 361003, China. zhibinli33@hotmail.com.|Epidemiology Research Unit, The First Affiliated Hospital, Xiamen University, Xiamen, China. zhibinli33@hotmail.com.
authors.forename: Zhibin
authors.initials: Z
authors.lastname: Li
mesh_terms: D050154:Adiposity; D001823:Body Composition; D015992:Body Mass Index; D002681:China; D003430:Cross-Sectional Studies; D005260:Female; D005353:Fibronectins / Q000097:blood*; D006706:Homeostasis; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000378:metabolism*; D016017:Odds Ratio; D012307:Risk Factors; D055105:Waist Circumference
chemical_list: C577593:FNDC5 protein, human; D005353:Fibronectins; D007328:Insulin
keywords: Adiposity; Insulin resistance; Irisin; Structural equation modeling