Table 1.
Characteristics of participants according to serum blood urea nitrogen quartiles
| Characteristics | BUN (mmol/L) | P‐trend | |||
|---|---|---|---|---|---|
| Q1 (<2.40) | Q2 (2.40‐2.91) | Q3 (2.91‐3.50) | Q4 (≥3.50) | ||
| No. of patients | 3209 (23.86) | 3509 (26.09) | 3225 (23.99) | 3505 (26.06) | |
| Maternal age (y) | 27.33 ± 4.07 | 27.67 ± 4.05 | 27.79 ± 4.13 | 27.70 ± 4.09 | .001 |
| Gravidity | |||||
| <2 | 1188 (37.02) | 1257 (35.82) | 1072 (33.24) | 1199 (34.21) | .007 |
| ≥2 | 2021 (62.98) | 2252 (64.18) | 2153 (66.76) | 2306 (65.79) | |
| Parity | |||||
| No | 1007 (31.38) | 980 (27.93) | 747 (23.16) | 647 (18.46) | <.001 |
| Yes | 2202 (68.62) | 2529 (72.07) | 2478 (76.84) | 2858 (81.54) | |
| Education attainment | |||||
| Junior middle school or below | 552 (17.20) | 557 (15.87) | 465 (14.42) | 457 (13.04) | <.001 |
| Senior high school | 2589 (80.68) | 2882 (82.13) | 2683 (83.19) | 2993 (85.39) | <.001 |
| College or higher | 68 (2.12) | 70 (1.99) | 77 (2.39) | 55 (1.57) | .225 |
| Baseline BMI, (kg/m2) | 21.20 ± 2.61 | 21.06 ± 2.66 | 20.98 ± 2.61 | 20.82 ± 2.62 | <.001 |
| Gestational weight gain (kg) | 14.87 ± 5.39 | 15.02 ± 5.38 | 15.01 ± 5.38 | 15.18 ± 5.46 | .027 |
| Systolic BP (mm Hg) | 110.85 ± 26.17 | 109.98 ± 19.92 | 110.46 ± 10.69 | 110.65 ± 18.48 | .065 |
| Diastolic BP (mm Hg) | 70.80 ± 18.20 | 70.00 ± 7.69 | 70.07 ± 7.75 | 70.24 ± 17.73 | .017 |
| BUN (mmol/L) | 2.10 (1.90‐2.26) | 2.65 (2.51‐2.80) | 3.19 (3.04‐3.30) | 4.00 (3.70‐4.43) | <.001 |
| FPG (mmol/L) | 4.61 ± 0.44 | 4.64 ± 0.46 | 4.66 ± 0.46 | 4.65 ± 0.47 | .002 |
| WBC (109/L) | 7.70 (6.50‐8.90) | 7.71 (6.54‐9.04) | 7.68 (6.50‐9.00) | 7.67 (6.42‐8.91) | .543 |
| Haemoglobin (g/L) | 125.50 ± 9.53 | 125.02 ± 9.96 | 125.14 ± 9.97 | 124.60 ± 10.28 | .001 |
| Creatinine (mmol/L) | 46.00 (40.30‐53.35) | 47.00 (41.40‐54.00) | 48.70 (42.80‐56.00) | 48.60 (41.40‐57.70) | <.001 |
| eGFR (mL/min per 1.73 m2) | 144.47 ± 16.69 | 143.41 ± 19.43 | 141.37 ± 18.16 | 142.24 ± 26.38 | <.001 |
Data given as mean ± SD, mean (IQR) or n (%).
Abbreviations: BMI, body mass index; BP, blood pressure; BUN, blood urea nitrogen; eGFR, estimated glomerular filtration rate; FPG, fasting plasma glucose; WBC, white blood cell.