RETN and metabolic disease: Pearson’s correlation between levels of adipsin (serum and FF), C5a, and various inflammatory and metabolic disease markers showed positive correlations between pre-IVF serum adipsin and levels of vitamin D (R = 0.5, p = 0.02), glucagon (R = 0.4, p = 0.03), leptin (R = 0.4, p = 0.01), resistin (R = 0.4, p = 0.02), and visfatin (R = 0.4, p = 0.02), but a negative correlation with total protein (R = −0.5, p = 0.03).