| Resident county, n (%) |
| Lin | 181 (14.1) | 110 (13.4) † | 14 (6.0) ‡§ | 150 (13.8) | 98 (12.5) † | 21 (6.2) ‡§ |
| Fenxi | 157 (12.2) | 242 (29.5) | 7 (3.0) | 113 (10.4) | 239 (30.5) | 71 (21.1) |
| Fangshan | 229 (17.8) | 170 (20.8) | 17 (7.3) | 191 (17.5) | 114 (14.5) | 20 (5.9) |
| Songtao | 120 (9.3) | 28 (3.4) | 43 (18.5) | 100 (9.2) | 29 (3.7) | 37 (11.0) |
| Liping | 100 (7.8) | 74 (9.0) | 110 (47.4) | 109 (10.0) | 87 (11.1) | 76 (22.6) |
| Pan | 498 (38.8) | 195 (23.8) | 41 (17.7) | 426 (39.1) | 217 (27.7) | 112 (33.2) |
| Boys, n (%) | 727 (56.6) | 467 (57.0) | 121 (52.2) | 601 (55.2) | 440 (56.1) | 169 (50.1) |
| Child age (months), median (25th, 75th) | 20 (13, 27) | 19 (11, 27) | 23 (17, 28) ठ| 20 (12, 27) | 20 (12, 27) | 22 (18, 29) ठ|
| Preterm children, n (%) | 39 (3.0) | 24 (2.9) | 2 (0.9) | 54 (5.0) | 47 (6.0) | 11 (3.3) |
| Minority ethnic of children, n (%) | 435 (33.9) | 199 (24.3) † | 167 (72.0) ‡§ | 394 (36.2) | 205 (26.1) † | 163 (48.4) ‡§ |
| Relationship of caregivers to the child, n (%) |
| Parents | 1243 (96.7) | 776 (94.7) | 0 (0.0) ‡§ | 1048 (96.2) | 733 (93.5) † | 0 (0.0) ‡§ |
| Grandparents | 39 (3.0) | 42 (5.1) | 229 (98.7) | 39 (3.6) | 47 (6.0) | 321 (95.3) |
| Others | 3 (0.2) | 1 (0.1) | 3 (1.3) | 2 (0.2) | 4 (0.5) | 16 (4.7) |
| Female gender of caregiver, n (%) | 1035 (80.5) | 809 (98.8) † | 187 (80.6) § | 938 (86.1) | 762 (97.2) † | 279 (82.8) § |
| Caregiver age (years), median (25th, 75th) | 27 (24, 31) | 26 (24, 30) | 51 (48, 56) ठ| 27 (24, 32) | 27 (24, 31) | 52 (47, 56) ठ|
| Education attainment of caregivers, n (%) |
| High school or above | 165 (12.9) | 123 (15.0) | 8 (3.4) ठ| 218 (20.0) | 158 (20.2) | 18 (5.3) ठ|
| Middle school | 694 (54.0) | 462 (56.4) | 42 (18.1) | 560 (51.4) | 423 (54.0) | 87 (25.8) |
| Primary school | 343 (26.7) | 186 (22.7) | 66 (28.4) | 249 (22.9) | 162 (20.7) | 104 (30.9) |
| Illiteracy | 83 (6.5) | 48 (5.9) | 116 (50.0) | 62 (5.7) | 41 (5.2) | 128 (38.0) |
| Depression among caregivers a, n (%) | 485 (40.0) | 291 (37.1) | 117 (50.6) ‡§ | 388 (35.9) | 249 (31.8) | 128 (38.0) § |
| Low household economic status b, n (%) | 180 (14.0) | 79 (9.6) † | 44 (19.0) § | 157 (14.4) | 122 (15.6) | 89 (26.4) ‡§ |
