The Graded Relationship between Glucose Tolerance Status in Pregnancy and Postpartum Levels of Low-Density-Lipoprotein Cholesterol and Apolipoprotein B in Young Women: Implications for Future Cardiovascular Risk

Abstract

Both gestational diabetes mellitus (GDM) and gestational impaired glucose tolerance (GIGT) identify women at risk of future cardiovascular disease, although the mediators of this risk are unknown. Because lipid factors can contribute to cardiovascular risk, we sought to characterize the relationship between gestational glucose tolerance status and lipid profile in pregnancy and the postpartum. Fasting lipids were measured in 482 women in pregnancy and at 3 months postpartum. Antepartum glucose challenge test (GCT) and oral glucose tolerance test (OGTT) defined four gestational glucose tolerance groups: GDM (n = 136), GIGT (n = 89), abnormal GCT with normal glucose tolerance (NGT) on OGTT (abnormal GCT NGT) (n = 170), and normal GCT with NGT on OGTT (normal GCT NGT) (n = 87). In pregnancy, there were no significant differences between the groups in total and low-density lipoprotein (LDL) cholesterol, triglycerides, total cholesterol to high-density lipoprotein (HDL) cholesterol ratio, apolipoprotein B (apoB), apolipoprotein A1 (apoA1), and apoB to apoA1 ratio. At 3 months postpartum, however, each of the following lipid parameters progressively increased from normal GCT NGT to abnormal GCT NGT to GIGT to GDM: total cholesterol (P = 0.0047), LDL (P = 0.0002), triglycerides (P = 0.0002), total cholesterol to HDL ratio (P < 0.0001), apoB (P = 0.0003), and apoB to apoA1 ratio (P = 0.0014). Furthermore, on multiple linear regression analyses, GDM emerged as an independent predictor of postpartum total cholesterol (t = 3.09, P = 0.0021), LDL (t = 3.81, P = 0.0002), triglycerides (t = 3.38, P = 0.0008), total cholesterol to HDL ratio (t = 3.76,P = 0.0002), apoB (t = 4.12, P < 0.0001), and apoB to apoA1 ratio (t = 3.07, P = 0.0023). GIGT was an independent predictor of postpartum total cholesterol to HDL ratio (t = 2.27, P = 0.0239), apoB (t = 2.04, P = 0.0416), and apoB to apoA1 ratio (t = 1.97, P = 0.049). Compared with their peers, women with GDM and GIGT have a more atherogenic lipid profile by 3 months postpartum, characterized by increased LDL and apoB.