Variables | Mild group N (%) |  | Moderate/severe group N (%) | Z/χ2 | P |
---|---|---|---|---|---|
Sex | Â | Â | Â | 1.400 | 0.237 |
 Male | 208 (83.5%) |  | 209 (79.5%) |  |  |
 Female | 41 (16.5%) |  | 54 (20.5%) |  |  |
Age (median (Q1-Q3)) | 3.5 (3–5) |  | 3 (2.5–4) | −3.250 | 0.010* |
Birth month | Â | Â | Â | 2.961 | 0.398 |
 Nov-Jan | 66 (26.5%) |  | 79 (30.0%) |  |  |
 Feb-Apr | 51 (20.5%) |  | 50 (19.0%) |  |  |
 May-Jul | 65 (26.1%) |  | 54 (20.5%) |  |  |
 Aug-Oct | 67 (26.9%) |  | 80 (30.4%) |  |  |
Place of residence | Â | Â | Â | 4.505 | 0.034* |
 Urban | 193 (77.5%) |  | 182 (69.2%) |  |  |
 Rural | 56 (22.5%) |  | 81 (30.8%) |  |  |
Caregivers | Â | Â | Â | 7.986 | 0.046* |
 Parents | 159 (63.9%) |  | 137 (52.1%) |  |  |
 Grandparents | 66 (26.5%) |  | 93 (35.4%) |  |  |
 Both parents and grandparents | 20 (8.0%) |  | 30 (11.4%) |  |  |
 Others | 4 (1.6%) |  | 3 (1.1%) |  |  |
Siblings | Â | Â | Â | 1.762 | 0.184 |
 Yes | 52 (20.9%) |  | 68 (25.9%) |  |  |
 No | 197 (79.1%) |  | 195 (74.1%) |  |  |
Age of mother during pregnancy (median (Q1-Q3)) | 28 (25–30) |  | 28 (24–31.75) | −0.710 | 0.478 |
Age of father during pregnancy (median (Q1-Q3)) | 29.5 (27–33) |  | 29 (26–33) | −0.297 | 0.767 |
Maternal education | Â | Â | Â | 7.132 | 0.008* |
 Junior college or above | 109 (43.8%) |  | 85 (32.3%) |  |  |
 Senior high school or below | 140 (56.2%) |  | 178 (67.7%) |  |  |
Paternal education | Â | Â | Â | 4.506 | 0.034* |
 Junior college or above | 104 (41.8%) |  | 86 (32.7%) |  |  |
 Senior high school or below | 145 (58.2%) |  | 177 (67.3) |  |  |
Household income (10,000 yuan) (median (Q1-Q3)) | 5 (4–7) |  | 5 (4–6) | −1.918 | 0.055 |
Family history of mental illness | Â | Â | Â | 0.001 | 0.973 |
 Yes | 31 (12.4%) |  | 33 (12.5%) |  |  |
 No | 218 (87.6%) |  | 230 (87.5%) |  |  |
Vitamin intake during pregnancy | Â | Â | Â | 2.795 | 0.424 |
 None | 29 (11.6%) |  | 43 (16.3%) |  |  |
 Folic acid | 139 (55.8%) |  | 139 (52.9%) |  |  |
 Multivitamins | 57 (22.9%) |  | 53 (20.2%) |  |  |
 Others | 24 (9.6%) |  | 28 (10.6%) |  |  |
Mode of delivery | Â | Â | Â | 0.026 | 0.872 |
 Vaginal | 85 (34.1%) |  | 88 (33.5%) |  |  |
 Cesarean | 164 (65.9%) |  | 175 (66.5%) |  |  |
Eating problems | Â | Â | Â | 0.247 | 0.619 |
 Yes | 111 (44.6%) |  | 123 (46.8%) |  |  |
 No | 138 (55.4%) |  | 140 (53.2%) |  |  |
Sleeping problems | Â | Â | Â | 0.529 | 0.467 |
 Yes | 74 (29.7%) |  | 86 (32.7%) |  |  |
 No | 175 (70.3%) |  | 177 (67.3%) |  |  |
Gastrointestinal problems | Â | Â | Â | 4.709 | 0.030* |
 Yes | 53 (21.3%) |  | 78 (29.7%) |  |  |
 No | 196 (78.7%) |  | 185 (70.3%) |  |  |
Comorbidity with ADHD | Â | Â | Â | 0.250 | 0.617 |
 Yes | 30 (12.0%) |  | 28 (10.6%) |  |  |
 No | 219 (88.0%) |  | 235 (89.4%) |  |  |