Table 3 Association between vitamin D status in the second trimester and the risk of GDM

All participants

Sufficiency (≥ 30 ng/mL)

1.00

1.00

Insufficiency (20–30 ng/mL)

1.98 (1.37, 2.87)

< 0.001

1.85 (1.28, 2.67)

0.001

Deficiency (< 20 ng/mL)

1.44 (0.91, 2.27)

0.119

1.37 (0.88, 2.14)

0.168

Overweight participants

Sufficiency (≥ 30 ng/mL)

1.00

1.00

Insufficiency (20–30 ng/mL)

3.23 (1.55, 6.70)

0.002

3.55 (1.75, 7.20)

0.001

Deficiency (< 20 ng/mL)

2.36 (0.95, 5.86)

0.065

2.38 (1.03, 5.53)

0.043

Non-overweight participants

Sufficiency (≥ 30 ng/mL)

1.00

1.00

Insufficiency (20–30 ng/mL)

1.60 (1.01, 2.53)

0.043

1.47 (0.92, 2.36)

0.106

Deficiency (< 20 ng/mL)

1.26 (0.74, 2.15)

0.392

1.21 (0.72, 2.04)

0.472

Participants ≥ 35 years

Sufficiency (≥ 30 ng/mL)

1.00

1.00

Insufficiency (20–30 ng/mL)

3.06 (1.41, 6.65)

0.005

2.88 (1.25, 6.61)

0.013

Deficiency (< 20 ng/mL)

1.70 (0.56, 5.13)

0.346

1.67 (0.53, 5.26)

0.378

Participants < 35 years

Sufficiency (≥ 30 ng/mL)

1.00

1.00

Insufficiency (20–30 ng/mL)

1.72 (1.15, 2.65)

0.012

1.67 (1.09, 2.56)

0.018

Deficiency (< 20 ng/mL)

1.39 (0.84, 2.30)

0.194

1.34 (0.82, 2.18)

0.246