Characteristics at first visit with paediatrician (7–45 days old)
| North n (%) | Centre n (%) | South n (%) | Total n (%) | P value | |
| Breast feeding | < 0.0001 * | ||||
| Exclusive | 1577 (67.9) | 639 (65.5) | 971 (56.7) | 3187 (63.6) | |
| Mixed breast feeding | 476 (20.4) | 252 (25.8) | 440 (25.6) | 1168 (23.3) | |
| Artificial formula only | 270 (11.6) | 84 (8.6) | 300 (17.5) | 654 (13.1) | |
| Usual sleep position | <0.0001* | ||||
| Supine | 2069 (90.3) | 849 (87.3) | 1444 (84.5) | 4362 (87.7) | |
| Side | 92 (4.0) | 65 (6.7) | 215 (12.6) | 372 (7.5) | |
| Prone | 130 (5.7) | 59 (6.1) | 50 (2.9) | 239 (4.8) | |
| Vitamin D prophylaxis ongoing/initiated at visit | 2.297 (98.7) | 942 (96.3) | 1.642 (95.6) | 4881 (97.4) | <0.0001* |
| Drug prescribed at visit (excluding vitamin D) | 108 (4.6) | 27 (2.8) | 41 (2.4) | 176 (3.5) | <0.0001* |
* Statistically significant