Introduction: Several cross-sectional studies evidence the association between hypovitaminosis D, obesity, insulin resistance (IR), and polycystic ovary syndrome (PCOS) cohorts, although the role of obesity per se is still debatable. Increased leptin-to-adiponectin ratio (L/A) and low-grade chronic inflammation markers, both due to accumulation of dysfunctional adipocytes, have been recently reported in PCOS. Aim of our study was to investigate the relative roles of obesity, low-grade chronic inflammation and dysfunctional adiposity in hypovitaminosis D in PCOS according to BMI.
Methods: Eighty-eight women (age 24.3±4.3 years; BMI range 1847 kg/m2; FerrimanGallwey score ≥8) were consecutively recruited in the study from those referred for PCOS to our unit (42 lean and 46 overweight-obese (O/O) subjects). Testosterone, sex hormone-binding globulin, fasting plasma glucose and insulin, 25-hydroxy vitamin D (25OHD), C-reactive protein (CRP), interleukin (IL) 6, leptin and adiponectin were measured using commercially available kits. homeostasis model assessment of IR (HOMA-IR), free androgen index (FAI), and L/A were calculated.
Results: In O/O PCOS women FAI, HOMA-IR, 25OHD, CRP, IL6, L/A, and waist were significantly higher compared to lean PCOS (P<0.001). In subgroup analyses, the strengths of the associations between all the study variables were similar between lean and O/O PCOS, out of the association between 25OHD and CPR and IL6 that retained an inverse statistical significance in only O/O PCOS women.
Conclusion: While lower 25OHD and higher L/A were associated in both lean and O/O PCOS, lower 25OHD with higher CRP and IL6 were evidenced only in O/O PCOS. In other terms, in the complex relationships between hypovitaminosis D and PCOS, L/A might represent an early marker of the negative effect of adiposity on circulating 25OHD levels, while an increasing amount of dysfunctional adipocytes were likely required to evidence the association of low 25OHD levels with different markers of low-grade chronic inflammation, such as CRP and IL6.
Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.
05 - 09 May 2012
European Society of Endocrinology