Table 1. Parental Characteristics.
| Parental characteristica | No. (%) | P value | ||
|---|---|---|---|---|
| All | Allergic diseases | |||
| No | Yes | |||
| Maternal age at delivery, y | ||||
| ≤24 | 3020 (20.6) | 1524 (25.2) | 1496 (17.4) | <.001 |
| 25-29 | 6967 (47.6) | 2645 (43.8) | 4322 (50.2) | |
| ≥30 | 4657 (31.8) | 1874 (31.0) | 2783 (32.4) | |
| Paternal age at delivery, y | ||||
| ≤24 | 1762 (11.7) | 930 (14.9) | 832 (9.4) | <.001 |
| 25-34 | 11 023 (73.0) | 4306 (68.9) | 6717 (75.8) | |
| ≥35 | 2320 (15.4) | 1101 (16.2) | 1309 (14.8) | |
| Family income (RMB), ¥b | ||||
| <6000 | 4957 (32.7) | 2482 (39.6) | 2475 (27.9) | <.001 |
| ≥6000 | 10 188 (67.3) | 3786 (60.4) | 6402 (72.1) | |
| Parity (No. of previous deliveries) | ||||
| <1 | 10 552 (69.7) | 4365 (69.6) | 6187 (69.7) | .94 |
| ≥2 | 4593 (30.3) | 1903 (30.4) | 2690 (30.3) | |
| Maternal smoking during pregnancy | ||||
| No | 14 887 (98.3) | 6138 (97.9) | 8749 (98.6) | .003 |
| Yes | 258 (1.7) | 130 (2.1) | 128 (1.4) | |
| Maternal alcohol intake during pregnancy | ||||
| No | 14 833 (97.9) | 6133 (97.8) | 8700 (98.0) | .50 |
| Yes | 312 (2.1) | 135 (2.2) | 177 (2.0) | |
| Paternal smoking during pregnancy | ||||
| No | 9789 (64.6) | 4099 (65.4) | 5690 (64.1) | .10 |
| Yes | 5356 (35.4) | 2169 (34.6) | 3187 (35.9) | |
| Family history of allergic disease | ||||
| No | 11 323 (74.8) | 5687 (90.7) | 5636 (63.5) | <.001 |
| Yes | 3822 (25.2) | 581 (9.3) | 3241 (36.5) | |
a
Data missing for some variables.
b
RMB, currency in circulation in China; ¥1 is equivalent to $1.