Circulating FGF21 levels are related to nutritional status and metabolic but not hormonal disturbances in polycystic ovary syndrome

Objective: The aim of this study was to analyse relationships between plasma fibroblast growth factor 21 (FGF21) levels and nutritional status, and metabolic and hormonal disturbances in polycystic ovary syndrome (PCOS) women. Design and setting: A cross-sectional study involving 85 PCOS (48 obese) and 72 non-PCOS women (41 obese) was conducted to evaluate the relationship between FGF21 levels and PCOS. Methods: Anthropometric parameters and body composition were determined. In the fasting state; serum concentrations of glucose, androgens, FSH, LH, SHBG, insulin and FGF21 were measured. Results: Plasma FGF21 levels were significantly higher in obese women compared with normal-weight women in both PCOS and non-PCOS subgroups (120.3 (18.2-698) vs 62.3 (16.4-323.6) pg/ml, P<0.05 and 87.2 (12.9-748.4) vs 62.9 (18.0-378.8) pg/ml, P<0.05 respectively). Additionally, circulating FGF21 levels were significantly higher in the obese PCOS subgroup compared with the non-PCOS subgroup (120.3 (18.2-698.0) vs 87.2 (12.9-748.4) pg/ml, P<0.05). Circulating FGF21 levels were proportional to BMI (R=0.27; P<0.001), body fat mass (R=0.24; P<0.01) and percentage (R=0.24; P<0.01), as well as waist circumference (R=0.26; P<0.01). Additionally, plasma insulin and homeostasis model assessment of insulin resistance (HOMA-IR) values were related to FGF21 levels (R=0.44; P<0.001 and R=0.19; P<0.05 respectively). In multiple regression analysis, circulating FGF21 level variability was explained by HOMA-IR values and fat percentage, as well as waist circumference, but not correlated with oestradiol levels and free androgen index values. Conclusions: Higher circulating FGF21 levels are related to nutritional status and insulin resistance independent of PCOS. Increased FGF21 is associated with metabolic but not hormonal disturbances.