Table 1.
Background characteristics — comparison of VP/VLBW and control samples, and groupwise dropouts.
| VP/VLBW |
Controls |
Between current samples: p | ||||||
|---|---|---|---|---|---|---|---|---|
| Current sample (n = 86) | Not included (n = 325) | Within group: p | Current sample (n = 100) | Not included (n = 208) | Within group: p | |||
| Sex: | Male | n = 54 (63%) | n = 158 (49%) | <.05 | n = 59 (59%) | n = 95 (46%) | p < .05 | n.s. |
| Female | n = 32 (37%) | n = 167 (51%) | n = 41 (41%) | n = 113 (54%) | ||||
| Age at examination (years) | 26.6 ± 0.6 | NA | NA | 26.8 ± 0.8 | NA | NA | <.1 | |
| Edinburgh Handedness Inventory | Right | n = 73 (84.9%) | NA | NA | n = 83 (83%) | NA | NA | >.9 |
| Ambidexter | n = 4 (4.7%) | NA | NA | n = 6 (6%) | NA | NA | ||
| Left | n = 8 (9.3%) | NA | NA | n = 9 (9%) | NA | NA | ||
| Missing | n = 1 (1.2%) | n = 2 (2%) | ||||||
| Gestational age (months) | 30.3 ± 2 | 30.6 ± 2.4 | n.s. | 39.8 ± 1 | 39.6 ± 1.2 | n.s. | <.001 | |
| Birth weight (g) | 1328 ± 321 | 1295 ± 304 | n.s. | 3419 ± 451 | 3366 ± 443 | n.s. | <.001 | |
| Multiple births | n = 23 (26.7%) | 80 (24.6%) | n.s. | n = 4 (4%) | 8 (3.8%) | n.s. | <.001 | |
| Maternal age (years) | 29.6 ± 4.7 | 28.2 ± 5.1 | <.05 | 29 ± 4.9 | 28.5 ± 4.8 | n.s. | n.s. | |
| Socioeconomic status at birth | Upper | n = 25 (29%) | n = 56 (17%) | <.05 | n = 32 (32%) | n = 60 (29%) | n.s. | n.s. |
| Middle | n = 37 (43%) | n = 136 (42%) | n = 44 (44%) | n = 78 (38%) | ||||
| Lower | n = 24 (28%) | n = 132 (41%) | n = 24 (24%) | n = 70 (34%) | ||||
| Complications | n = 86 | n = 323 | n = 100 | n = 208 | ||||
| Pre-pregnancy | 1.5 ± 0.8 | 1.3 ± 0.8 | n.s. | 1.1 ± 0.8 | 1.1 ± 0.8 | n.s. | .001 | |
| Pregnancy | 2.1 ± 1.2 | 2.5 ± 1.2 | <.05 | 0.7 ± 0.8 | 0.9 ± 1 | n.s. | <.001 | |
| Birth | 4.7 ± 1.4 | 4.5 ± 1.4 | n.s. | 2.3 ± 1.6 | 2 ± 1.5 | n.s. | <.001 | |
| Neonatal | 8.9 ± 2.6 | 9.5 ± 2.7 | <.05 | 0.3 ± 0.6 | 0.4 ± 0.7 | n.s. | <.001 | |
| Duration of neonatal treatment (DNTI) | 54.1 ± 30 (n = 85) | 57.5 ± 37.4 (n = 323) | n.s. | NA | NA | NA | NA | |
| Intensity of neonatal treatment (INTI) | 11.6 ± 3.8 (n = 85) | 11.8 ± 3.9 (n = 321) | n.s. | NA | NA | NA | NA | |
| Ventilation (days) | 12.5 ± 17.7 | 16.2 ± 21.8 | n.s. | NA | NA | NA | NA | |
| Duration of hospitalization (days) | 72.3 ± 26.4 | 79 ± 38.8 | n.s. | 7 ± 3.1 | 7.4 ± 3.9 | n.s. | <.001 | |
| Intraventricular hemorrhage | n = 86 | n = 323 | ||||||
| None | n = 71 (82.6%) | n = 251 (77.7%) | n.s. | NA | NA | NA | NA | |
| Stage 1 | n = 4 (4.7%) | n = 26 (8%) | NA | NA | NA | |||
| Stage 2 | n = 7 (8.1%) | n = 20 (6.2%) | NA | NA | NA | |||
| Stage 3 | n = 3 (3.5%) | n = 17 (5.3%) | NA | NA | NA | |||
| Stage 4 | n = 1 (1.2%) | n = 9 (2.8%) | NA | NA | NA | |||
| Cerebral palsy (56 months) | n = 86 | n = 310 | <.05 | n = 100 | n = 208 | NA | <.01 | |
| Severity # | Grade 1 and 2 | n = 6 (7%) | n = 24 (7.7%) | 0 (0%) | 0 (0%) | |||
| Grade 3 and 4 | n = 0 (0.0%) | n = 23 (7.4%) | 0 (0%) | 0 (0%) | ||||
| Neurosensory deficits (56 months), non-corrected | n = 82 | n = 269 | n = 100 | n = 207 | ||||
| Blindness | n = 1 (1.2%) | n = 2 (0.7%) | n.s. | 0 (0%) | 0 (0%) | NA | n.s. | |
| Deafness | n = 0 (0.0%) | n = 0 (0.0%) | NA | 0 (0%) | 2 (1%) | n.s. | NA | |
| Griffith Scales of Baby Abilities | 5 months | 102.1 ± 16.3 (n = 85) | 93.6 ± 21.2 (n = 299) | <.001 | 106.9 ± 10.6 | 106.2 ± 11 | n.s. | <.05 |
| 20 months | 100.2 ± 10.2 (n = 83) | 89.5 ± 22.8 (n = 287) | <.001 | 107.5 ± 6.3 | 105.8 ± 6.8 | <.05 | <.001 | |
| Kaufman assessment Battery for children | 6; 3 years | 92.6 ± 11.1 (n = 77) | 83.6 ± 17.1 (n = 254) | <.001 | 101.7 ± 10.1 | 99.9 ± 11.5 | n.s. | <.001 |
| 8; 5 years | 96.7 ± 10.5 (n = 79) | 85.6 ± 18.9 (n = 262) | <.001 | 102.7 ± 8.7 (n = 99) | 100 ± 10.6 (n = 206) | <.05 | <.001 | |
| WAIS-III: full-scale IQ | 26 years | 95.2 ± 12.2 | 84.4 ± 19.1 (n = 117) | p < .001 | 102.7 ± 12.2 | 102.6 ± 13 (n = 97) | n.s. | <.001 |
Within-group analyses compared present preterm-born (VP/VLBW) and term-born (Controls) samples with those preterm-born and term-born participants, respectively, not included in this study. Between-group analyses compared current preterm-born and term-born samples. For variables where data were not available for all participants, the actual group size is indicated separately. # Cerebral palsy: Grade 1 & 2 = can walk independently or with stick, Grade 3 & 4 = restricted mobility requiring wheel chair or no mobility. Abbreviations: WAIS-III — Wechsler Adult Intelligence Scale, Third edition. NA — not available. n.s. — not significant.