Table 2.
Participant demographics by phenotypes
| Characteristic | POLD-reversible | POLD-fixed | pPRISm | pDysanapsis | Preterm—normal spirometry (PTc) | Term |
| Number | 24 | 18 | 49 | 32 | 421 | 195 |
| Per cent of preterm population | 4.4% | 3.3% | 9.0% | 5.9% | 77.4% | – |
| Male | 9 (38%) | 9 (50%) | 28 (57%) | 17 (53%) | 216 (51%) | 100 (51%) |
| Caucasian ethnicity | 21 (88%) | 17 (94%) | 49 (100%) | 30 (94%) | 398 (95%) | 188 (96%) |
| Current age, years (SD) | 9.6 (9.6) | 10.0 (10) | 10.3 (1.3)*†‡ | 9.4 (9.4) | 9.6 (1.3) | 9.7 (1.2) |
| Current height, cm (SD) | 137.7 (10.0) | 140.4 (10.4) | 143.5 (10.3) | 138.7 (10.2) | 139.5 (10.4) | 142.0 (9.3) |
| Current height, z-score (SD) | 0.243 (1.19) | 0.315 (0.96) | 0.551 (1.36) | 0.544 (1.06) | 0.580 (1.14)* | 0.889 (1.09) |
| Current weight, kg (SD) | 33.6 (11.7) | 34.4 (9.2) | 36.4 (10.4) | 36.6 (11.9) | 35.2 (10.6) | 37.0 (10.4) |
| Current weight, z-score (SD) | 0.090 (1.46) | 0.226 (1.02) | 0.237 (1.42) | 0.729 (1.22) | 0.512 (1.12) | 0.744 (1.07) |
| Current body mass index, kg/m2 (SD) | 17.3 (3.9) | 17.2 (2.4) | 17.4 (3.2) | 18.6 (4.1) | 17.7 (3.3) | 18.1 (3.3) |
| Current body mass index, z-score (SD) | −0.048 (1.50) | 0.070 (1.16) | −0.039 (1.35) | 0.627 (1.34) | 0.311 (1.21) | 0.438 (1.18) |
| z-score change from birth to current weight (SD) | 0.458 (1.515) | 0.232 (1.370) | 0.410 (1.717) | 0.919 (1.252) | 0.240 (1.497)** | 0.682 (1.226) |
| Median gestational age, weeks, (range) | 30 (24, 34)*** | 29.5 (24, 34)*** | 32 (25, 34)*** | 32.5 (23, 34)*** | 32 (23, 34)*** | 40 (37, 42) |
| Median birth weight, g (range) | 1120 (550, 2353)*** | 1349 (625, 2608)*** | 1644 (500, 2750)*** | 1691 (620, 2810)*** | 1757 (450, 3912)*** | 3430 (2155, 4916) |
| Birth weight, z-score (SD) | −0.368 (1.48) | −0.006 (1.18) | −0.173 (1.24) | −0.19 (1.17) | 0.272 (1.36) | 0.062 (0.97) |
| Intrauterine growth restriction | 9 (38%) §‡‡‡ *** | 4 (22%)** | 7 (14%)* | 7 (22%)*** | 49 (12%)** | 9 (5%) |
| Antenatal steroids | 21 (88%)*** | 16 (94%)*** | 44 (90%)*** | 27 (96%)*** | 343 (87%)*** | 4 (2%) |
| Bronchopulmonary dysplasia | 10 (42%) †‡‡ *** | 8 (44%) †‡‡ *** | 12 (25%)*** | 4 (13%)*** | 74 (18%)*** | 0 (0%) |
| Wheeze ever | 19 (79%) §‡‡ *** | 13 (72%) ‡ *** | 25 (51%)** | 23 (72%)‡‡*** | 201 (48%)*** | 51 (26%) |
| Recent wheeze (<12 months) | 14 (58%)§§‡‡‡*** | 7 (39%)** | 11 (22%) | 18 (56%)§§‡‡‡*** | 102 (24%)** | 25 (13%) |
| Doctor diagnosed asthma | 9 (38%)‡‡‡*** | 6 (33%)‡ *** | 10 (20%)** | 11 (36%)‡‡‡*** | 52 (12%)** | 10 (5%) |
| Inhalers last 12 months | 10 (42%) §‡‡‡ *** | 6 (33%) ‡ *** | 8 (16%)* | 13 (41%) § ‡‡‡*** | 56 (13%)** | 12 (6%) |
| Current preventer inhaler | 7 (29%)‡‡*** | 5 (28%) ‡ *** | 7 (14%)** | 9 (28%)‡‡*** | 39 (9%)* | 8 (4%) |
| Maternal smoking in pregnancy | 2 (8%) | 2 (11%) | 5 (10%) | 5 (17%)* | 48 (12%)* | 11 (6%) |
| Current maternal smoking | 4 (17%)* | 1 (6%) | 5 (10%) | 6 (19%)** | 58 (14%)*** | 8 (4%) |
| FEV1, %predicted (SD) | 63.8 (10.2)§§§†††‡‡‡*** | 69.7 (10.6)†††‡‡‡*** | 75.8 (4.5)†††‡‡‡*** | 89.2 (6.1) ‡‡‡ *** | 95.6 (8.9) | 95.7 (10.2) |
| FEV1, z-score (SD) | −3.04 (0.81) §§§†††‡‡‡ *** | −2.58 (0.89) †††‡‡‡ *** | −2.07 (0.37) †††‡‡‡ *** | −0.94 (0.53) ‡‡ ** | −0.38 (0.77) | −0.38 (0.87) |
| FEF25%–75%, %predicted (SD) | 36.2 (10.6) §§§†††‡‡‡ *** | 41.6 (10.0) §§§‡‡‡ *** | 63.1 (10.2) ‡‡‡ *** | 54.7 (6.4) ‡‡ ** | 84.1 (16.3) | 86.4 (19.3) |
| FEF25%–75%, z-score (SD) | −3.24 (0.64)§§§†††‡‡‡*** | −3.05 (0.79) §§§††‡‡‡ *** | −1.8 (0.54) ‡‡‡ *** | −2.2 (0.36) ‡‡ ** | −0.75 (0.75) | −0.66 (0.91) |
| FVC, %predicted (SD) | 82.8 (9.0)†††‡‡‡*** | 85.8 (9.1)†††‡‡‡*** | 77.6 (6.0)†††¶‡‡‡*** | 106.1 (8.0) | 96.4 (9.6) ††† | 96.2 (10.3) ††† |
| FVC, z-score (SD) | −1.51 (0.80) †††‡‡‡ *** | −1.22 (0.77) †††‡‡‡ *** | −1.94 (0.52) †††¶‡‡‡*** | 0.51 (0.67) | −0.32 (0.82) ††† | −0.33 (0.88) ††† |
| FEV1/FVC, ratio (SD) | 0.68 (0.08)§§§††‡‡‡*** | 0.71 (0.07)§§§‡‡‡*** | 0.85 (0.06) | 0.74 (0.03) §§§‡‡‡ *** | 0.87 (0.05) | 0.87 (0.06) |
| FEV1/FVC, z-score (SD) | −2.58 (0.63) §§§‡‡‡ *** | −2.35 (0.56) §§§‡‡‡ *** | −0.33 (0.90) | −2.06 (0.29) §§§‡‡‡ *** | −0.12 (0.90) | −0.07 (0.98) |
Data are given as means and SDs for continuous variables, or number and percentage for categorical variables, unless specifically stated.
Significant vs ¶POLD – Fixed, §pPRISm, †pDysanapsis, ‡PTc, * Tc (single symbol denotes significance level <0.05, double symbol <0.01, triple symbol<0.001).
FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; pDysanapsis, dysanapsis of prematurity; POLD, prematurity-associated obstructive lung disease; pPRISm, prematurity-associated PRISm.