Table 2 Characteristics of participants at approximately 1 year postpartum based on breastfeeding practice groups

Clinical characteristics

Duration of any breastfeeding (years)

1.1 (1.0–1.2)

1.0 (1.0–1.2)

1.0 (1.0–1.1)

0.156

Current contraceptive use

0.602

 No or non-hormonal method

41 (71.9)

14 (53.8)

31 (66.0)

 Combined estrogen-progestin method

6 (10.5)

4 (15.4)

5 (10.6)

 Progestin-only method

10 (17.5)

8 (30.8)

11 (23.4)

Weight (kg)

69.1 ± 16.2

69.0 ± 11.2

59.1 ± 9.6^{c, d}

< 0.001

BMI (kg/m²)

27.7 ± 6.0

28.0 ± 4.5

24.1 ± 3.4^{c, d}

< 0.001

Systolic BP (mmHg)

119.0 (112.0–126.5)

126.0 (117.0–133.0)

114.0 (109.0–121.0)^{c, d}

< 0.001

Diastolic BP (mmHg)

74.0 (67.0–82.0)

76.5 (71.0–82.3)

72.0 (66.0–79.0)

0.108

WC (cm)

90.5 ± 13.9

90.2 ± 8.7

87.8 ± 12.3^{c, d}

< 0.001

Laboratory tests

FPG (mg/dL)

100.0 (90.0–106.5)

97.5 (94.0–108.3)

93.0 (87.0–101.0)^{c, d}

0.030

HbA1c (%)

5.6 (5.3–5.9)

5.6 (5.4–5.7)

5.5 (5.2–5.8)

0.675

Fasting insulin (mU/L)

11.0 (8.4–20.9)

17.1 (9.6–23.4)

8.3 (5.3–11.8)^{c, d}

< 0.001

Fasting C-peptide (ng/mL)

2.4 (1.9–3.2)

2.8 (2.2–3.3)

1.8 (1.5–2.3)^{c, d}

< 0.001

HOMA-IR

2.8 (1.9–5.3)

4.3 (2.4–5.7)

1.9 (1.2–2.7)^{c, d}

< 0.001

Cholesterol (mg/dL)

183.0 (169.0–208.0)

197.0 (176.8–228.0)

191.0 (175.0–221.0)

0.160

TG (mg/dL)

101.0 (73.0–165.5)

97.5 (83.5–167.8)

79.0 (50.0–113.0)^{c, d}

0.009

LDL-cholesterol (mg/dL)

118.0 (109.0–147.0)

141.0 (109.3–170.5)

130.0 (114.0–152.0)

0.050

HDL-cholesterol (mg/dL)

49.0 (44.5–56.0)

50.0 (41.8–58.8)

61.0 (55.0–70.0)^{c, d}

< 0.001

AST (U/L)

21.0 (19.0–25.5)

22.0 (18.0–27.5)

21.0 (16.0–23.0)

0.076

ALT (U/L)

17.0 (8.0–23.5)

12.5 (8.0–22.8)

12.0 (8.0–18.0)

0.462

ALP (U/L)

74.0 (59.5–84.5)

79.5 (69.0–93.3)

81.0 (63.0–97.0)

0.235

FibroScan measurements

CAP value (dB/m)

279.0 (191.5–324.0)

257.5 (205.3–317.3)

219.0 (189.0–271.0)^c

0.034

Liver stiffness value (kPa)

4.4 (3.6–5.4)

4.6 (3.9–5.2)

4.4 (3.5–5.5)

0.803