Higher circulating irisin levels in patients with polycystic ovary syndrome:a meta-analysis.

Insulin resistance (IR) has been reported to be highly associated with the pathogenesis of polycystic ovary syndrome (PCOS). Although irisin, a newly identified myokine that may be closely associated with IR, has been implicated in the development of PCOS, the results are still ambiguous. We performed this meta-analysis to compare the circulating irisin levels between PCOS and healthy women and assess the association of irisin with IR. Published works were retrieved from PubMed and Embase databases using combinations of 'irisin' and ('polycystic ovary syndrome' or 'PCOS'). Eight studies involving 1918 PCOS patients and 528 controls were included in the meta-analysis. Publication bias was observed using a funnel plot and Egger's regression asymmetry test. The pooled data indicated that the levels of irisin were at least 45.78 ng/ml [95% confidence interval (CI)] (12.45, 79.12, p = .007) higher in patients with PCOS than that in the healthy controls. Additionally, we did not observe a significant correlation between circulating irisin levels and IR in study populations, although the results may not be reliable for small sample sizes. The current meta-analysis suggested that irisin might contribute to the development of PCOS independent of IR.