Table 1.
Baseline characteristics of study participants by gestational diabetes mellitus (GDM) status
| Total (N = 906,319) | No GDM (N = 856,126) | GDM (N = 50,193) | Standardized difference* | |
|---|---|---|---|---|
| Age at index pregnancy (years) | 29.74 ± 5.58 | 29.59 ± 5.56 | 32.32 ± 5.28 | 0.5 |
| Ethnicity | ||||
| Chinese | 53,136 (5.9) | 48,404 (5.7) | 4,732 (9.4) | 0.14 |
| General population | 811,524 (89.5) | 770,600 (90.0) | 40,924 (81.5) | 0.24 |
| South Asian | 41,659 (4.6) | 37,122 (4.3) | 4,537 (9.0) | 0.19 |
| Neighborhood income quintile | ||||
| 1 (lowest) | 207,754 (22.9) | 193,980 (22.7) | 13,774 (27.4) | 0.11 |
| 2 | 186,621 (20.6) | 175,611 (20.5) | 11,010 (21.9) | 0.03 |
| 3 | 184,881 (20.4) | 174,598 (20.4) | 10,283 (20.5) | 0 |
| 4 | 183,203 (20.2) | 174,241 (20.4) | 8,962 (17.9) | 0.06 |
| 5 (highest) | 140,591 (15.5) | 134,634 (15.7) | 5,957 (11.9) | 0.11 |
| Rurality | ||||
| Rural | 62,756 (6.9) | 60,443 (7.1) | 2,313 (4.6) | 0.10 |
| Semiurban | 150,534 (16.6) | 145,025 (16.9) | 5,509 (11.0) | 0.17 |
| Urban | 693,029 (76.5) | 650,658 (76.0) | 42,371 (84.4) | 0.21 |
| Gestational age at delivery (weeks) | 38.92 ± 1.84 | 38.96 ± 1.84 | 38.23 ± 1.72 | 0.41 |
| Preterm delivery (gestational age ≤36 weeks) | 57,775 (6.4) | 52,974 (6.2) | 4,801 (9.6) | 0.13 |
| Number of previous live births, mean | 0.52 ± 0.90 | 0.52 ± 0.89 | 0.64 ± 1.02 | 0.13 |
| Parity (number of previous births) | ||||
| 0 | 595,792 (65.7) | 565,249 (66.0) | 30,543 (60.9) | 0.11 |
| 1 | 199,252 (22.0) | 187,466 (21.9) | 11,786 (23.5) | 0.04 |
| ≥2 | 111,275 (12.3) | 103,411 (12.1) | 7,864 (15.7) | 0.10 |
| Pregestational hypertension | 19,749 (2.2) | 17,342 (2.0) | 2,407 (4.8) | 0.15 |
| Preeclampsia | 54,176 (6.0) | 49,142 (5.7) | 5,034 (10.0) | 0.16 |
| Prevalent chronic kidney disease | 2,587 (0.3) | 228 (0.5) | 2,815 (0.3) | 0.02 |
| Proportion without 50-g GCT data | 546,732 (60.3) | 517,894 (60.5) | 28,838 (57.5) | 0.06 |
| 50-g GCT, mmol/L | 6.53 ± 1.72 | 6.32 ± 1.48 | 9.85 ± 1.89 | 2.08 |
| Preexisting CVD | 8,455 (0.9) | 7,924 (0.9) | 531 (1.1) | 0.01 |
| Postpartum diabetes | 20,459 (2.3) | 11,759 (1.4) | 8,700 (17.3) | 0.57 |
| Postpartum hypertension | 28,704 (3.2) | 25,481 (3.0) | 3,223 (6.4) | 0.16 |
| Postpartum CAD | 491 (0.1) | 442 (0.1) | 49 (0.1) | 0.02 |
Data are mean ± SD or N (%). CAD, coronary artery disease. CVD, cardiovascular disease. GCT, glucose challenge test.
*
An absolute standardized difference of >0.1 is considered to indicate imbalance between the groups.