Bacopoulou F, et al. – The variations and predictors of serum 25–hydroxyvitamin D concentrations were gauged in this research, among women with polycystic ovary syndrome (PCOS) compared with non–PCOS controls, matched for body mass index. The data disclosed that serum 25–hydroxyvitamin D could be positively speculated through serum calcium and negatively by luteinizing hormone in women with PCOS. It could be predicted negatively by waist–to–hip ratio and positively by fasting glucose in both PCOS and non–PCOS women, independently of the presence of obesity.