Impact of interlukin-6 on central obesity measures in women with polycystic ovarian syndrome

Abstract

Our aim was to investigate the relationship between plasma interleukin-6 (IL-6) levels with different measures of central obesity among Saudi women with and without polycystic ovarian syndrome (PCOS). One hundred and sixty-four Saudi females, between 22 and 38 years of age, with and without PCOS were enrolled in this case-control study. Physical examination and laboratory tests were completed for every subject. 2/3 of the study population were obese. Fasting serum insulin, plasma IL-6 levels and insulin resistance show significant increase among POCS than the controls (p<.05). Based on linear regression analysis, C-reactive protein (hs-CRP) was the only independent predictor of plasma IL-6 levels, accounting for 4% of the variability in plasma IL-6 (β = 0.217, p=.005, 95% CI: 0.049–0.275). Coexistence of metabolic and inflammatory factors in PCOS females is accompanied by central obesity which overpowers the effect of insulin resistance, contributing to higher plasma levels of IL-6 and CRP.

Impact statement

• What is already known on this subject? Polycystic ovary syndrome (PCOS) is a cluster of many cardiovascular risk factors, but is also known as an inflammatory condition. Insulin resistance and abdominal obesity are classic components of PCOS. High circulatory levels of inflammatory markers in PCOS patients have been reported but it remains unclear whether their elevation is related to PCOS itself, or are a function of abdominal adiposity.

• What the results of this study add? The relationship between plasma interleukin-6 levels and different measures of central obesity was investigated among Saudi women with and without PCOS. Elevations of proinflammatory cytokines and inflammatory markers were reported in PCOS patients independently of insulin resistance. It remains to be established whether the proinflammatory state in PCOS is primarily due to inflamed adipose tissue.

• What the implications are of these findings for clinical practice and/or further research? The present study demonstrates that coexistence of metabolic and inflammatory factors in PCOS females are accompanied by central obesity which overpowers the effect of insulin resistance, contributing to higher plasma levels of IL-6 and CRP. Future studies including a larger population are needed to investigate the mechanisms by which IL-6 and hs-CRP promote cardiovascular risk in PCOS patients.

Keywords:

• IL-6
• hs-CRP
• waist circumference
• waist height ratio
• waist hip ratio

Acknowledgements

The authors would like to thank all the individuals who took part in the study.

Authors’ contributions

The contributions of the authors are as follows: EA designed research; NM and AK provided cases; SG conducted subject recruitments and data collection; EA analysed data and wrote the paper; EA had primary responsibility for final content. All authors read and approved the final manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was supported by a grant number (KACST, 30-37) from the King Abdulaziz City for Science and Technology (KACST). The funding source has no role in publication.