Table 1 Characteristics of participants
Characteristics | All | Non-case group* | Case group* | P-value§ |
|---|---|---|---|---|
Total, n (%) | 183,449 (100) | 158,305 (86.3) | 25,144 (13.7) | / |
Grade, n (%) |  |  |  | < 0.001†|
 1–6 | 136,771 (74.6) | 117,450 (74.2) | 19,321 (76.8) |  |
 7–9 | 33,013 (18.0) | 29,014 (18.3) | 3999 (15.9) |  |
 10–12 | 13,665 (7.45) | 11,841 (7.48) | 1824 (7.25) |  |
Age, Years, n (%)# |  |  |  | < 0.001†|
 6–10 | 114,026 (62.2) | 97,603 (61.7) | 16,423 (65.3) |  |
 11–15 | 59,374 (32.4) | 51,961 (32.8) | 7413 (29.5) |  |
  > 15 | 10,049 (5.48) | 8741 (5.52) | 1308 (5.20) |  |
 Mean (SD) | 9.94 (2.99) | 9.97 (3.00) | 9.76 (2.96) | < 0.001¶ |
Sex, n (%) | ||||
 Male | 98,565 (53.7) | 83,995 (53.1) | 14,570 (58.0) | < 0.001‡ |
 Female | 84,884 (46.3) | 74,310 (46.9) | 10,574 (42.1) |  |
 Birth weight, kg, Mean (SD) | 2.99 (0.42) | 2.98 (0.42) | 3.02 (0.43) | < 0.001¶ |
Neonatal feeding, n (%) |  |  |  | < 0.001‡ |
 Breast feeding | 80,718 (44.0) | 70,723 (44.7) | 9995 (39.8) |  |
 Breast+ formula feeding | 71,363 (38.9) | 60,184 (38.0) | 11,179 (44.5) |  |
 Formula feeding | 31,368 (17.1) | 27,398 (17.3) | 3970 (15.8) |  |
Delivery, n (%) |  |  |  | < 0.001‡ |
 Vaginal delivery | 107,830 (58.8) | 94,232 (59.5) | 13,598 (54.1) |  |
 Cesarean | 75,619 (41.2) | 64,073 (40.5) | 11,546 (45.9) |  |
Delivery date, n (%) |  |  |  | < 0.001‡ |
 On the due date | 50,595 (27.6) | 45,627 (28.8) | 4968 (19.8) |  |
 Overdue | 44,520 (24.3) | 37,855 (23.9) | 6665 (26.5) |  |
 Before the due date | 88,334 (48.2) | 74,823 (47.3) | 13,511 (53.7) |  |
Diseases in pregnancy, n (%) | ||||
 Hypertension | 3005 (1.64) | 2472 (1.56) | 533 (2.12) | < 0.001‡ |
 Diabetes | 4290 (2.34) | 3329 (2.10) | 961 (3.82) | < 0.001‡ |
 Intrahepatic cholestasis | 486 (0.26) | 383 (0.24) | 103 (0.41) | < 0.001‡ |
 Hypothyroidism | 590 (0.32) | 470 (0.30) | 120 (0.48) | < 0.001‡ |
 Hyperthyroidism | 760 (0.41) | 626 (0.40) | 134 (0.53) | 0.002‡ |
 Anemia | 13,515 (7.37) | 10,701 (6.76) | 2814 (11.2) | < 0.001‡ |
 Viral hepatitis | 1950 (1.06) | 1604 (1.01) | 346 (1.38) | < 0.001‡ |
 Other | 1331 (0.73) | 968 (0.61) | 363 (1.44) | < 0.001‡ |
 Any disease above | 23,175 (12.6) | 18,434 (11.6) | 4741 (18.9) | < 0.001‡ |
 Only child, n (%) | 70,832 (38.6) | 59,201 (37.4) | 11,631 (46.3) | < 0.001‡ |
 One or both parents’ education> 12 years, n (%) | 133,304 (72.7) | 113,317 (71.6) | 19,987 (79.5) | < 0.001‡ |
Father smoking, n (%) |  |  |  | 0.129†|
 Never smoked | 90,370 (49.3) | 78,172 (49.4) | 12,198 (48.5) |  |
 Quit for > 1 year | 14,584 (7.95) | 12,410 (7.84) | 2174 (8.65) |  |
 Quit for < 1 year | 4291 (2.34) | 3698 (2.34) | 593 (2.36) |  |
 Current smoking | 74,204 (40.5) | 64,025 (40.4) | 10,179 (40.5) |  |
Mother smoking, n (%) |  |  |  | 0.519†|
 Never smoked | 181,814 (99.1) | 156,903 (99.1) | 24,911 (99.1) |  |
 Quit for > 1 year | 672 (0.37) | 575 (0.36) | 97 (0.39) |  |
 Quit for < 1 year | 218 (0.12) | 189 (0.12) | 29 (0.12) |  |
 Current smoking | 745 (0.41) | 638 (0.40) | 107 (0.43) |  |
Average Household monthly income per person, US$, n (%) |  |  |  | < 0.001†|
  < 735 | 61,248 (33.4) | 54,362 (34.3) | 6886 (27.4) |  |
 735–1764 | 74,842 (40.8) | 64,471 (40.7) | 10,371 (41.3) |  |
  > =1764 | 47,359 (25.8) | 39,472 (24.9) | 7887 (31.4) |  |