Table 1—

Insulin, proinsulin, and C-peptide secretion by glucose tolerance status

CharacteristicNGTIGTGDMP*
n933948
Age (years)33.2 ± 4.532.8 ± 4.734.0 ± 4.30.3980
Weeks’ gestation29.2 ± 2.729.7 ± 1.929.1 ± 2.20.4268
Prepregnancy BMI (kg/m2)23.9 ± 4.524.1 ± 4.224.7 ± 5.10.5977
Insulin (pmol/l)
    Fasting58 (40–77)63 (47–81)74 (54–104)0.0036
    AUC1,320 (925–1,837)1,561 (1,091–1,920)1,709 (1,267–2,538)0.0046
Proinsulin (pmol/l)
    Fasting17.7 (9.3–29.4)15.2 (7.9–22.9)17.2 (9.1–27.3)0.5286
    AUC70.5 (51.7–91.5)66 (39.6–83.4)57.7 (44.9–102.3)0.6586
C-peptide (pmol/l)
    Fasting742 ± 288758 ± 258863 ± 3300.0654
    AUC7,076 (5,571–9,611)7,928 (6,071–9,200)8,717 (6,877–9,748)0.1156
C-peptide–to–insulin ratio
    Fasting12.3 (10.5–15.1)12.3 (9.5–14.9)11.2 (8.9–13.0)0.0623
    AUC21.1 (17.1–24.9)19.6 (16.4–24.9)17.3 (14.8–21.2)0.0211
Proinsulin-to-insulin ratio
    Fasting0.277 (0.16–0.60)0.197 (0.13–0.43)0.221 (0.11–0.50)0.1317
    AUC0.292 (0.18–0.48)0.230 (0.13–0.36)0.224 (0.11–0.36)0.0155
Proinsulin–to–C-peptide ratio
    Fasting0.024 (0.01–0.04)0.022 (0.01–0.04)0.019 (0.01–0.03)0.4414
    AUC0.039 (0.02–0.05)0.035 (0.02–0.05)0.028 (0.02–0.05)0.3465
  • Data are means ± SD for age, weeks’ gestation, prepregnancy BMI, and fasting C-peptide. All other values are medians (interquartile range).

  • *

    * P values refer to overall differences across groups as derived from ANOVA. P values in bold are <0.05.