Table 3.
The characteristics of the subjects in each time point based on panel data 1 (According to longitudinal community-based retrospective birth cohort study conducted in Changsha in 2013–2014).
| Variable | Months Old | p-Value | ||||
|---|---|---|---|---|---|---|
| 1 | 3 | 6 | 8 | 12 | ||
| Number of subjects (n) | 519 | 519 | 519 | 519 | 519 | |
| Weight (kg) | 4.61 (0.61) | 6.77 (1.63) | 8.45 (2.32) | 9.19 (2.38) | 9.97 (1.03) | <0.001 |
| Number of breast-feedings per day (n) | 9.7 (4.6) | 7.7 (4.6) | 5.1 (4.7) | 3.0 (2.8) | 1.3 (2.5) | <0.001 |
| Breast feeding (%) | 502 (96.7) | 478 (92.1) | 413 (79.6) | 318 (61.3) | 161 (31.0) | <0.001 |
| Number of formula per day (n) | 1.2 (2.6) | 1.5 (2.5) | 1.9 (2.3) | 2.4 (2.6) | 2.6 (2.7) | <0.001 |
| Formula feeding (%) | 146 (28.1) | 174 (33.5) | 269 (51.8) | 350 (67.4) | 433 (83.4) | <0.001 |
| Complimentary feeding (%) | 2 (0.4) | 23 (4.3) | 483 (93.1) | 513 (98.8) | 517 (99.6) | <0.001 |
| Sleep problems (%) | 18 (3.46) | 16 (3.08) | 18 (3.46) | 16 (3.08) | 24 (4.62) | 0.344 |
| Sleep duration (hours) | 17.78 (1.89) | 16.11 (1.67) | 14.78 (1.60) | 13.67 (1.30) | 12.29 (1.90) | <0.001 |
| Time of outdoor activities (hours) | 0.16 (0.88) | 1.65 (0.72) | 2.14 (0.94) | 2.45 (0.86) | 2.77 (1.34) | <0.001 |
| Taking Vitamin D (n) | 482 (92.7) | 512 (98.7) | 507 (97.7) | 505 (97.3) | 496 (95.6) | <0.001 |
1 Data are expressed as means (standard deviation) or number (percentages).