Table 1. Characteristics of START and BiB study participants included in the analysis.
| START | BiB | |||||
|---|---|---|---|---|---|---|
| No GDM | GDM | p Value | No GDM | GDM | p Value | |
| N (%) | 759 (75) | 253 (25) | – | 3809 (88.8) | 481 (11.2) | – |
| Age, years | 29.8 (3.8) | 31.6 (4) | 5.55×10–10 | 27.7 (5) | 30.5 (5.4) | 1.40×10–22 |
| Height, cm | 162.5 (6.27) | 161.13 (6.01) | 0.002 | 159.9 (5.69) | 158.3 (5.66) | 6.19×10–08 |
| Weight, kg a | 61.7 (11.7) | 65.6 (12.9) | 2.00×10–05 | 64.8 (14.1) | 71.1 (15.1) | 2.22×10–16 |
| BMI, kg/m2 b | 23.4 (4.3) | 25.3 (4.9) | 4.93×10–08 | 25.4 (5.2) | 28.4 (5.8) | 5.89×10–23 |
| Parity, n (%) | ||||||
| 0 | 328 (44.3%) | 78 (31.1%) | 0.001 | 1189 (32.2%) | 129 (27.4%) | 5.03×10–07 |
| 1 | 299 (40.4%) | 122 (48.6%) | 1026 (27.8%) | 94 (20%) | ||
| 2 or more | 114 (15.4%) | 51 (20.3%) | 1473 (39.9%) | 248 (52.7%) | ||
| Post-secondary education, n (%) | 641 (84.6%) | 208 (82.2%) | 0.43 | 952 (29.4%) | 110 (26.3%) | 0.22 |
| Country of origin/ancestry, n (%) | ||||||
| India | 567 (74.7%) | 160 (63.2%) | 0.001 | 175 (5.2%) | 19 (4.3%) | 0.37 c |
| Pakistan | 163 (21.5%) | 74 (29.2%) | 3198 (94.2%) | 425 (95.5%) | ||
| Other | 29 (3.8%) | 19 (7.5%) | 23 (0.7%) | 1 (0.2%) | ||
| Born in South Asia, n (%) | 671 (88.5%) | 225 (88.9%) | 0.95 | 1836 (54.2%) | 291 (65.7%) | 6.50×10–06 |
| Years in recruitment country (Canada/UK) d | 6.4 (5.8) | 7.4 (5.8) | 0.02 | 9.3 (9) | 12.1 (9.4) | 3.88×10–06 |
| Parental history of diabetes, n (%) | 282 (37.3%) | 142 (56.1%) | 2.25×10–07 | 891 (27.4%) | 170 (38.9%) | 8.88×10–07 |
| Vegetarians, n (%) | 266 (37%) | 84 (34.6%) | 0.54 | 12 (1.3%) | 1 (1.1%) | >0.99 c |
| Low diet quality, n (%) | 180 (24) | 88 (35.1) | 8.00×10–04 | – | – | – |
| Polygenic risk score (z-scores) | –0.11 (1) | 0.347 (0.93) | 1.51×10–08 | –0.04 (0.99) | 0.32 (1.04) | 4.98×10–12 |
| Polygenic risk score | ||||||
| Tertile 1 | 240 (37.7%) | 39 (19.4%) | 2.74×10–06 | 1309 (34.4%) | 117 (24.3%) | 7.60×10–10 |
| Tertile 2 | 206 (32.4%) | 73 (36.3%) | 1291 (33.9%) | 142 (29.5%) | ||
| Tertile 3 | 190 (29.9%) | 89 (44.3%) | 1209 (31.7%) | 222 (46.2%) | ||
| Fasting plasma glucose, mmol/L | 4.27 (0.32) | 5.02 (0.83) | 5.51×10–32 | 4.53 (0.41) | 5.34 (1.14) | 3.18×10–43 |
| 1 hr post-load glucose, mmol/L | 7.31 (1.38) | 10.26 (2.02) | 6.04×10–57 | – | – | – |
| 2 hr post-load glucose, mmol/L | 5.96 (1.16) | 8.47 (2.16) | 1.53×10–42 | 5.49 (1.02) | 9.14 (1.97) | 1.57×10–155 |
| Area under curve glucose, mmol.hr e | 12.43 (1.83) | 17.02 (2.89) | 2.27×10–63 | 10.02 (1.21) | 14.48 (2.77) | 3.82×10–133 |
Characteristics of participants with available PRS and GDM IADPSG, FPG, 1 hr, 2 hr post-load glucose levels or AUC glucose data. Presented data are means (standard deviation) unless otherwise indicated. p Values are calculated from Chi-squared test for categorical variables and independent t-test for continuous variables. a Pre-pregnancy values in START vs. weight at antenatal clinic (average 12 completed weeks of pregnancy) in BiB. b Derived using height measured at initial visit (in both studies) and pre-pregnancy weights (START) or antenatal clinic weights (BiB).c Approximation may be incorrect due to small counts. d Canada for START samples and UK for BiB. e Derived using fasting, 1 hr and 2 hr post-load measurements in START vs. fasting and 2 hr post-load measurements in BiB. Abbreviations: AUC, area under the curve glucose; BiB, Born in Bradford; BMI, body mass index; GDM, gestational diabetes mellitus; IADPSG, International Association of Diabetes and Pregnancy Study Groups; START, south Asian birth cohort; T2D, type 2 diabetes; UK, United Kingdom; vs., versus.