Interleukin-6 Levels in Women with Polycystic Ovary Syndrome: A Systematic Review and Meta-Analysis

Zheng Peng, Yifan Sun, Xiaolan Lv, Hongyu Zhang, Chunming Liu, Shengming Dai, Zheng Peng, Yifan Sun, Xiaolan Lv, Hongyu Zhang, Chunming Liu, Shengming Dai

Abstract

Background: The change of serum interleukin-6(IL-6) levels in women with polycystic ovary syndrome (PCOS), as well as the relations between IL-6 levels and body mass index (BMI), insulin resistance(IR) and androgen status of PCOS patients, are not fully understood.

Methods: A literature search was performed in October 2015 using PubMed, Embase and the Cochrane Library databases to identify studies. Random-effects model was used to estimate the standardized mean differences (SMDs) with 95% confidence intervals (CIs).

Results: Twenty articles with 25 case-control studies included 1618 women (922 PCOS patients and 696 controls) were included in this study. IL-6 levels in controls were significantly lower than that of PCOS patients (SMD = 0.78, 95%CI = 0.41-1.16, P<0.001), with significant heterogeneity across studies (I2 = 91% and P<0.001). Meta-regression analysis model indicated IR status was the main source of heterogeneity (P = 0.005). Results from group analysis suggested that high IL-6 levels in PCOS were significantly associated with Homeostasis Model Assessment of Insulin Resistance (HOMA2-IR) ratio and total testosterone ratio (T ratio), and was found in both lean and obese women with PCOS. Cumulative meta-analysis results indicated the total effect size (SMD) had tend to be stable since 2012(0.79 to 0.92).

Conclusions: A high IL-6 level is not an intrinsic characteristic of PCOS, but may be a useful monitoring biomarker for the treatment of PCOS.

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Fig 1. Flow diagram of included studies…
Fig 1. Flow diagram of included studies for this meta-analysis.
Fig 2. The pooled quantitative synthesis for…
Fig 2. The pooled quantitative synthesis for IL-6 levels in PCOS patients compared with controls.
Fig 3. Summary of categorical meta-analysis.
Fig 3. Summary of categorical meta-analysis.
Fig 4. Cumulative meta-analysis.
Fig 4. Cumulative meta-analysis.

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