Table 1.
Characteristics of postpartum subjects
| Anthropometric and Metabolic Characteristics | Lactating versus Formula Groups |
||
|---|---|---|---|
| Lactating (n = 18) | Formula (n = 10) | P Value | |
| Age (years) | 34 ± 4 | 34 ± 4 | 0.859 |
| Parity | 3.1 ± 0.8 | 2.7 ± 1.3 | 0.640 |
| History of GDM in last pregnancy (%) | 67 | 40 | 0.243 |
| Exclusive lactation (%) | 72 | 0 | <0.001 |
| BMI at 6-week postpartum (kg/m2) | 29.8 ± 4.5 | 30.6 ± 2.0 | 0.356 |
| Intrahepatic lipid (%) | 9.9 ± 5.7 | 10.7 ± 6.0 | 0.860 |
| Body composition by DEXA | |||
| Fat mass (kg) | 29.9 ± 9.4 | 29.1 ± 4.0 | 0.532 |
| Fat-free mass (kg) | 42.9 ± 6.1 | 42.6 ± 5.2 | 0.878 |
| HDL cholesterol (mmol/l) | 1.3 ± 0.3 | 1.1 ± 0.2 | 0.020 |
| Total plasma TG (mmol/l) | 1.4 ± 0.6 | 2.0 ± 1.1 | 0.133 |
| VLDL-TG (mmol/l) | 0.4 ± 0.3 | 0.9 ± 0.8 | 0.020 |
| FFA (mmol/l) | 0.60 ± 0.14 | 0.59 ± 0.13 | 0.768 |
| HbA1c (%) | 5.7 ± 0.3 | 5.6 ± 0.3 | 0.104 |
| Fasting glucose (mg/dl) | 84 ± 8 | 86 ± 5 | 0.768 |
| Fasting insulin (μU/ml) | 2.6 ± 2.1 | 4.5 ± 2.4 | 0.027 |
| HOMA-IR | 1.0 ± 1.0 | 1.5 ± 0.9 | 0.027 |
| Adipo-IR | 2.7 ± 3.3 | 4.3 ± 2.6 | 0.011 |
| Matsuda index | 11.9 ± 9.8 | 6.9 ± 4.4 | 0.133 |
| First-phase Stumvoll (μU/ml) | 97 ± 61 | 170 ± 82 | 0.007 |
| Second-phase Stumvoll (μU/ml) | 28 ± 15 | 45 ± 20 | 0.014 |
| Insulin secretion sensitivity index 2 | 2.32 ± 1.55 | 2.34 ± 1.04 | 0.471 |
| Fasting EGP (mg/kg FFM/min) | 4.3 ± 0.9 | 3.3 ± 0.5 | 0.002 |
| Prolactin (ng/ml) | 242 ± 138 | 14 ± 9 | <0.001 |
| Total Adiponectin (μg/ml) | 4.1 ± 1.2 | 3.9 ± 1.0 | 0.588 |
| Leptin (ng/ml) | 5.1 ± 4.0 | 6.8 ± 2.5 | 0.031 |
| Estradiol (pg/ml) | 29 ± 17 | 75 ± 29 | <0.001 |
| Progesterone (ng/ml) | 0.49 ± 0.01 | 1.52 ± 2.20 | 0.028 |
| Fasting RQa | 0.82 ± 0.08 | 0.85 ± 0.04 | 0.122 |
| Clamp RQa | 0.85 ± 0.07 | 0.89 ± 0.05 | 0.136 |
Adipo-IR, adipose tissue insulin resistance; GDM, gestational diabetes; HOMA-IR, homeostatic model of insulin resistance; RQ, respiratory quotient; TGs, triacylglycerols.
All data are mean ± SD. Subjects were women at 6-week postpartum who were either lactating or feeding their infants with formula. Mann-Whitney tests were used for unpaired cross-sectional analyses.
a
A two-way ANOVA was also used on RQ because this variable was measured under basal and insulin-stimulated conditions (feeding group P = 0.145, time P = 0.003, interaction P = 0.408).