Table 1. Sample characteristics of the weighted BLS Phase II study participants according to gestational age groups (cases with severe neurological impairment excluded) at 8;5 years.
| <32 w GA | 32–33 w GA | 34–36 w GA | 37–38 w GA | 39–41 w GA | ||
| n = 255 | n = 90 | n = 209 | n = 186 | n = 586 | ||
| GA | 29.55 (1.59) | 32.52 (0.50) | 35.10 (0.76) | 37.52 (0.50) | 39.92 (0.67) | |
| Birth weight | 1294 (348) | 1656 (379) | 2207 (558) | 2809 (562) | 3364 (524) | |
| OPTI score1 | 9.55 (2.66) | 7.92 (2.60) | 5.48 (2.83) | 3.61 (2.53) | 2.63 (2.14) | |
| Ventilation (duration/days) | 19 (23) | 5 (9) | 1 (4) | 0 (2) | 0 (1) | |
| Hospitalization (days) | 83 (41) | 53 (22) | 29 (20) | 16 (16) | 12 (19) | |
| Neonatal risk score | ||||||
| none | 0% | 0% | 5% | 14% | 17% | |
| low | 0% | 2% | 17% | 27% | 35% | |
| moderate | 0% | 23% | 31% | 38% | 34% | |
| high | 0% | 74% | 46% | 21% | 14% | |
| very high | 100% | 0% | 0% | 0% | 0% | |
| Child sex (male) | 57% | 48% | 51% | 48% | 50% | |
| Family SES | low | 36% | 35% | 35% | 34% | 35% |
| medium | 43% | 37% | 29% | 31% | 25% | |
| high | 21% | 28% | 36% | 35% | 40% | |
1
Higher OPTI scores indicate less optimal neonatal course. Data is presented as mean (SD) for continuous variables and percentages (%) for categorical variables.