Table 1.
Sample characteristics, stratified by gender
| All Population Group | Allergen Test Subgroup | |||||
|---|---|---|---|---|---|---|
| Boy (n = 3289) | Girl (n = 2947) | χ2/t | Boy (n = 1975) | Girl (n = 1902) | χ2/t | |
| n (%) | n (%) | n (%) | n (%) | |||
| Demographic characteristics | ||||||
| Age (years); mean (SD) | 5.16 (0.87) | 5.15 (0.88) | 0.318 | 5.15 (0.87) | 5.14 (0.89) | 0.251 |
| Childhood overweight/ obesity | 666 (20.3%) | 469 (16.0%) | 19.768*** | 418 (21.3%) | 298 (15.7%) | 19.508*** |
| Child’s sleep duration on weekdays (≥10 h./day) | 557 (16.9%) | 496 (16.8%) | 0.013 | 377 (17.1%) | 309 (16.3%) | .466 |
| Child’s sleep duration on weekends (≥10 h./day) | 960 (29.3%) | 980 (33.3%) | 12.001*** | 612 (31.1%) | 620 (32.7%) | 1.167 |
| Child’s screen exposure frequency (≥5 times./week) | 436 (13.3%) | 400 (13.6%) | 0.134 | 250 (12.7%) | 250 (13.1%) | 0.204 |
| Child’s exercise frequency (≥1 h./day) | 1450 (44.1%) | 1225 (41.6%) | 4.025* | 909 (46.0%) | 803 (42.2%) | 5.694* |
| Family income # | 0.265 | 0.993 | ||||
| > 8000RMB | 1705 (51.8%) | 1519 (51.5%) | 1030 (52.2%) | 963 (50.6%) | ||
| 4000- 8000RMB | 1228 (37.3%) | 1117 (37.9%) | 727 (36.8%) | 728 (38.3%) | ||
| < 4000RMB | 356 (10.8%) | 311 (10.6%) | 218 (11.0%) | 211 (11.1%) | ||
| Family structure | 0.587 | 0.001 | ||||
| Single parent | 89 (2.7%) | 81 (2.7%) | 51 (2.6%) | 49 (2.6%) | ||
| Nuclear family | 1864 (56.7%) | 1697 (57.6%) | 1141 (57.8%) | 1098 (57.7%) | ||
| Extended family | 1336 (40.6%) | 1169 (39.7%) | 783 (39.6%) | 755 (39.7%) | ||
| Mother’s education level | 6.026* | 4.590 | ||||
| College and above | 2442 (74.2%) | 2243 (76.1%) | 1464 (74.1%) | 1458 (76.7%) | ||
| Secondary education | 509 (15.5%) | 454 (15.4%) | 310 (15.7%) | 285 (15.0%) | ||
| Primary education | 338 (10.3%) | 250 (8.5%) | 201 (10.2%) | 159 (8.4%) | ||
| Father’s education level | 2.524 | 2.290 | ||||
| College and above | 2439 (74.2%) | 2234 (75.8%) | 1456 (73.7%) | 1440 (75.7%) | ||
| Secondary education | 564 (17.1%) | 482 (16.4%) | 347 (17.6%) | 316 (16.6%) | ||
| Primary education | 286 (8.7%) | 231 (7.8%) | 172 (8.7%) | 146 (7.7%) | ||
| First-degree relative with allergies | 897 (27.3%) | 767 (26.0%) | 1.234 | 471 (23.8%) | 427 (22.5%) | 1.064 |
| Obstetric and parental health condition | ||||||
| Gestational weeks | 2.022 | 2.113 | ||||
| Premature delivery | 248 (7.6%) | 202 (6.9%) | 142 (7.2%) | 124 (6.6%) | ||
| Post-term delivery | 128 (3.9%) | 130 (4.5%) | 69 (3.5%) | 81 (4.3%) | ||
| Term delivery | 2890 (88.5%) | 2589 (88.6%) | 1754 (89.3%) | 1679 (89.1%) | ||
| Delivery mode | 6.525* | 7.401** | ||||
| Cesarean delivery | 1717 (52.2%) | 1443 (49.0%) | 1025 (51.9%) | 904 (47.5%) | ||
| Vaginal delivery/ midwifery | 1572 (47.8%) | 1504 (51.0%) | 950 (48.1%) | 998 (52.5%) | ||
| Mother’s age at delivery | 0.612 | 1.101 | ||||
| ≥ 30 | 1286 (39.6%) | 1139 (39.2%) | 765 (39.2%) | 731 (39.0%) | ||
| 25–29 | 1458 (44.9%) | 1332 (45.9%) | 875 (44.8%) | 864 (46.1%) | ||
| ≤ 24 | 500 (15.4%) | 433 (14.9%) | 311 (15.9%) | 278 (14.8%) | ||
| Full breastfeeding ≥6 month | 1885 (57.3%) | 1754 (59.5%) | 3.112 | 1151 (58.3%) | 1117 (58.7%) | 0.081 |
| Gestational smoking exposure | 71 (2.2%) | 63 (2.1%) | 0.003 | 35 (1.8%) | 39 (2.1%) | 0.401 |
| Gestational drinking | 84 (2.6%) | 2878 (97.7%) | 0.294 | 47 (2.4%) | 46 (2.4%) | 0.006 |
| Gestational hypertension | 60 (1.8%) | 85 (2.9%) | 7.690** | 33 (1.7%) | 45 (2.4%) | 2.374 |
| Gestational diabetes | 149 (4.5%) | 142 (4.8%) | 0.290 | 87 (4.4%) | 82 (4.3%) | 0.020 |
| Gestational anemia | 189 (5.7%) | 200 (6.8%) | 2.875 | 113 (5.7%) | 124 (6.5%) | 1.075 |
| Pre-pregnancy overweight/obesity | 328 (10.0%) | 267 (9.1%) | 1.453 | 203 (10.3%) | 163 (8.6%) | 3.269 |
| Environmental condition | ||||||
| Farmlands and orchards | 574 (17.5%) | 518 (17.6%) | .017 | 329 (16.7%) | 305 (16.0%) | 0.274 |
| Chemical emission sources | 82 (2.5%) | 87 (3.0%) | 1.242 | 45 (2.3%) | 48 (2.5%) | 0.249 |
| Smog-emitting factory | 79 (2.4%) | 91 (3.1%) | 2.758 | 41 (2.1%) | 56 (2.9%) | 2.995 |
| Large garbage dump | 232 (7.1%) | 208 (7.1%) | .000 | 136 (6.9%) | 129 (6.8%) | .898 |
| Respiratory allergic disease | ||||||
| Asthma | 533 (16.2%) a | 380 (12.9%) a | 13.635*** | 150 (7.6%) b | 78 (4.1%) b | 21.370*** |
| Wheeze | 586 (17.8%) a | 427 (14.5%) a | 12.650*** | 165 (8.4%) b | 90 (4.7%) b | 20.693*** |
| Allergic rhinitis | 802 (24.4%) a | 509 (17.3%) a | 47.357*** | 225 (11.4%) b | 129 (6.8%) b | 24.818*** |
* p < 0.05, **p < 0.01, ***p < 0.001; #Family income is calculated as RMB/person/month, RMB is China’s currency (yuan)
as Children only with screened respiratory allergies. b Children with both screened respiratory allergies and allergen test positive