Maternal serum osteocalcin at 11-14 weeks of gestation in gestational diabetes mellitus

Background Recent studies support that osteocalcin (OC), apart from its skeletal role, is implicated in glucose homoeostasis. Aims of this study were to examine the first-trimester maternal serum concentrations of OC in pregnancies that developed gestational diabetes mellitus (GDM) and to create a first-trimester prediction model for GDM. Design Case-control study in a prospective cohort of pregnant women. Maternal serum levels of OC were measured in 40 cases that developed GDM and 94 unaffected controls. First-trimester biophysical parameters, biochemical indices, maternal-pregnancy characteristics, and OC concentrations were assessed in relation to GDM occurrence. Results In the GDM group, first-trimester OC serum levels were increased compared to the control group (mean = 8.81 ng/mL, SD = 2.59 vs. mean = 7.34 ng/ml, SD = 3.04, P = 0.0058). Osteocalcin was independent of first-trimester biophysical and biochemical indices. Osteocalcin alone (OR = 1.21, CI: 1.02-1.43, P = 0.023) was a significant predictor of GDM [Model R-2 = 0.04, area under the curve (AUC) = 0.61, CI: 0.55-0.72, P < 0.001]. The combination of maternal and pregnancy characteristics with OC resulted in an improved prediction model for GDM (Model R-2 = 0.21, AUC = 0.80, CI: 0.71-0.88, P < 0.001). The combined model yields a sensitivity of 72.2% for 25% false-positive rate. Conclusions First-trimester maternal serum levels of OC are increased in GDM pregnancies. Osteocalcin combined with maternal and pregnancy characteristics provides an effective screening for GDM at 11-14 weeks.