Table 2 Odds ratios and 95% confidence intervals of gestational diabetes by different groups of pre-pregnancy BMI and seasons.

From: Seasonal variation and its interaction with pre-pregnancy BMI for GDM: a large population-based study in Tianjin, China

 

No. of subjects

No. of cases

Crude prevalence (%)

Odds ratios (95% confidence intervals)

Model 1

Model 2

Model 3

Pre-pregnancy BMI group, kg/m2

   < 18.5

11,641

1181

10.1

0.55 (0.52–0.59)

0.66 (0.62–0.71)

0.67 (0.62–0.71)

   18.5–< 24

67,349

11,426

17.0

1.00

1.00

1.00

   24–< 28

23,382

6735

28.8

1.98 (1.91–2.05)

1.60 (1.54–1.66)

1.59 (1.53–1.66)

   ≥ 28

10,267

4112

40.1

3.27 (3.13–3.42)

2.19 (2.07–2.31)

2.17 (2.06–2.30)

Seasons

   Spring

29,792

6124

20.6

1.00

1.00

1.00

   Summer

35,650

7029

19.7

0.95 (0.91–0.99)

1.00 (0.96–1.05)

1.00 (0.96–1.05)

   Autumn

30,211

6406

21.2

1.04 (1.00–1.08)

1.17 (1.12–1.23)

1.15 (1.09–1.20)

   Winter

16,986

3895

22.9

1.15 (1.10–1.20)

1.23 (1.17–1.30)

1.22 (1.16–1.29)

  1. Significant values are in bold.
  2. Model 1, Univariate analyses.
  3. Model 2, Adjusted for age, height, education, Han-ethnicity, cigarette smoking, alcohol drinking, family history of diabetes, variables at first antenatal care visit (gestational age, fasting glucose level, and systolic blood pressure), and variables at GDM screening (gestational age and weight gain).
  4. Model 3, Adjusted for variables in model 2 and also seasons (in pre-pregnancy BMI analyses), and pre-pregnancy BMI (in seasons analysis).
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