Table 1

Demographic, clinical, and metabolic characteristics of study population stratified into two groups: women in whom β-cell function did not decline between 3 and 12 months postpartum (nondecliners) and women in whom β-cell function declined between 3 and 12 months postpartum (decliners)

NondeclinersDeclinersP
n7492
At 3 months postpartum
 Age (years)35.3 [31.8–38.5]35.2 [33.8–38.3]0.4204
 Ethnicity (%)0.4097
  White77.072.8
  Asian13.510.9
  Other9.516.3
 Family history of diabetes (%)62.253.30.2492
 Current smoking (%)4.16.50.7325
 Current breastfeeding (%)97.391.30.1876
 Blood pressure (mmHg)
  Systolic108 [104–117]111 [103–116]0.6593
  Diastolic65 [59–70]64 [59–71]0.9634
 Physical activity
  Sport index2.0 [1.8–2.5]1.8 [1.5–2.5]0.6019
  Leisure-time index2.8 [2.5–3.3]2.8 [2.5–3.3]0.8009
 Waist circumference (cm)87 [82–99]90 [84–96]0.5303
 Weight (kg)70.2 [59.0–81.0]69.9 [62.1–80.7]0.7014
 BMI (kg/m2)26.5 [23.2–31.2]26.6 [24.0–30.2]0.6745
 Fasting insulin (pmol/L)36.5 [28.0–59.0]26.0 [20.0–49.5]0.0130
 Whole-body insulin sensitivity
  Matsuda index8.3 [5.7–14.0]9.8 [6.0–12.9]0.5413
 Hepatic insulin sensitivity
  1/HOMA-IR0.94 [0.56–1.32]1.3 [0.65–1.71]0.0112
  Fasting C-peptide:insulin15.6 [12.9–21.5]18.5 [14.5–27.0]0.0115
 β-Cell function
  ISSI-2785 [624–952]914 [748–1,207]0.0004
 OGTT
  Fasting glucose (mmol/L)4.8 [4.3–5.0]4.7 [4.3–5.0]0.1234
  30-min glucose (mmol/L)8.4 [7.4–9.5]8.7 [7.5–9.8]0.5027
  1-h glucose (mmol/L)8.6 [7.1–10.1]8.7 [7.2–10.0]0.9948
  2-h glucose (mmol/L)6.4 [5.3–7.3]6.7 [5.5–7.9]0.4479
  AUCgluc14.1 [12.3–15.8]14.2 [12.4–15.9]0.9288
 Glucose tolerance status (%)0.1356
  NGT78.472.8
  Isolated IFG2.70
  Isolated IGT17.627.2
  Combined IFG and IGT1.40
At 12 months postpartum
 Current breastfeeding (%)96.083.70.0123
 Physical activity
  Sport index2.1 [1.8–3.0]2.0 [1.8–2.5]0.3252
  Leisure-time index3.0 [2.8–3.5]3.0 [2.8–3.3]0.7867
  Work index2.9 [2.5–3.4]2.9 [2.4–3.4]0.7499
 Waist circumference (cm)85 [79–96]89 [82–95]0.2181
 Weight (kg)68.1 [56.5–78.0]68.3 [59.3–78.7]0.3084
 BMI (kg/m2)25.4 [21.5–29.4]25.9 [23.4–29.3]0.2976
 Fasting insulin (pmol/L)31.0 [20.0–48.0]45.5 [27.5–73.0]0.0015
 Whole-body insulin sensitivity
  Matsuda index9.1 [5.8–13.9]7.2 [4.4–10.9]0.0436
 Hepatic insulin sensitivity
  1/HOMA-IR1.11 [0.73–1.68]0.73 [0.45–1.18]0.0015
  Fasting C-peptide:insulin17.7 [14.0–23.9]15.1 [10.9–20.9]0.0116
 β-Cell function
  ISSI-21,034 [825–1,241]710 [572–902]<0.0001
 OGTT
  Fasting glucose (mmol/L)4.8 [4.5–4.9]4.9 [4.6–5.2]0.0570
  30-min glucose (mmol/L)8.0 [7.1–9.3]8.7 [7.8–9.8]0.0070
  1-h glucose (mmol/L)7.4 [5.8–9.2]9.1 [7.4–10.5]<0.0001
  2-h glucose (mmol/L)5.9 [4.9–7.3]6.7 [5.8–7.9]0.0007
  AUCgluc12.6 [10.8–14.8]14.8 [12.7–16.8]<0.0001
 Glucose tolerance status (%)0.3613
  NGT78.473.9
  Isolated IFG1.40
  Isolated IGT20.323.9
  Combined IFG and IGT00
  Diabetes02.2
Baseline-adjusted changes between 3 and 12 months
 Change in sport index0.16 [0.07]0.26 [0.08]0.3903
 Change in leisure-time index0.16 [0.05]0.24 [0.06]0.2940
 Change in waist−1.3 [0.7]−2.1 [0.8]0.4594
 Change in BMI−0.5 [0.2]−1.1 [0.2]0.0585
 Change in weight−1.5 [0.5]−2.9 [0.5]0.0482
 Change in Matsuda index−0.8 [0.6]0.2 [0.7]0.2701
 Change in 1/HOMA-IR−0.31 [0.05]0.07 [0.05]<0.0001
 Change in fasting C-peptide:insulin−2.6 [1.1]1.6 [1.2]0.0107
  • Baseline-adjusted changes are shown as adjusted mean [SE] and are adjusted for the value at 3 months postpartum. All other continuous data are shown as median [interquartile range]. Categorical data are shown as percentages. P values refer to differences between the two groups as determined by Kruskal-Wallis test for continuous variables and either χ2 test or Fisher exact test for categorical variables. AUCgluc, area under the glucose curve; IFG, impaired fasting glucose; IGT, impaired glucose tolerance; NGT, normal glucose tolerance.