Table 1. General characteristics at each check-up period by BW groups.
| BW group | No. (%) or mean (± SD) | ||||
|---|---|---|---|---|---|
| LBW (n = 2,312) | NBW (n = 34,332) | HBW (n = 1,405) | P value | ||
| BW, kg | 2.25 ± 0.31 | 3.23 ± 0.32 | 4.14 ± 0.17 | ||
| Sex | < 0.001 | ||||
| Male | 1,012 (44.0) | 17,469 (50.9) | 899 (64.0) | ||
| SES | 0.960 | ||||
| 1 | 67 (2.9) | 967 (2.8) | 39 (2.8) | ||
| 2 | 514 (22.3) | 7,612 (22.2) | 326 (23.2) | ||
| 3 | 643 (27.9) | 9,831 (28.6) | 407 (29.0) | ||
| 4 | 584 (25.4) | 8,663 (25.2) | 334 (23.8) | ||
| 5 | 494 (21.5) | 7,259 (21.1) | 299 (21.3) | ||
| Feeding | < 0.001 | ||||
| Breastfeed | 724 (31.9) | 16,487 (48.4) | 673 (47.9) | ||
| Formula milk | 1,071 (47.1) | 10,780 (31.6) | 416 (29.6) | ||
| Mixed | 477 (21.0) | 6,816 (20.0) | 303 (22.5) | ||
BW = birth weight, SES = socioeconomic status, SD = standard deviation, LBW = low birth weight, NBW = normal birth weight, HBW = high birth weight.