Table 1.
Background characteristics from the mid-adulthood spirometry assessment.
| 1. BPD-VLBW | 2. Non-BPD-VLBW | 3. (all) VLBW | 4. Term (reference) | p-value between 1 and 4 | p-value between 2 and 4 | p-value between 3 and 4 | |
|---|---|---|---|---|---|---|---|
| Number of participants | 20 | 95 | 115 | 142 | |||
| HeSVA | 16 | 61 | 77 | 83 | |||
| NTNU | 4 | 34 | 38 | 59 | |||
| Maternal background characteristics | Mean (SD) or n (%) | Mean (SD) or n (%) | Mean (SD) or n (%) | Mean (SD) or n (%) | |||
| Maternal age (years) | 29.5 (5.5) | 30.2 (4.5) | 30.1 (4.7) | 30.05 (4.8) | 0.66 | 0.84 | 0.98 |
| Height (cm) | 163.9 (7.3) | 165.2 (6.0) | 165.0 (6.2) | 166.1 (5.6) | 0.15 | 0.27 | 0.16 |
| Smoking during pregnancya | 2 (20.0%) | 12 (26.1%) | 14 (25.0) | 11 (16.9) | 0.81 | 0.24 | 0.27 |
| Parental educational attainment | 0.73 | 0.11 | 0.12 | ||||
| Basic or less | 4 (21.1%) | 19 (20.4%) | 23 (20.5%) | 15 (11.5%) | |||
| Upper secondary | 4 (21.1%) | 15 (16.1%) | 19 (17.0%) | 28 (21.4%) | |||
| Lower-level tertiary | 5 (26.3%) | 32 (34.4%) | 37 (33.0%) | 37 (28.2%) | |||
| Upper-level tertiary | 6 (31.6%) | 27 (29.0%) | 33 (29.5%) | 51 (38.9%) | |||
| Study participant characteristics | |||||||
| Sex, women | 12 (60.0%) | 56 (58.9%) | 68 (59.1%) | 82 (57.7%) | 0.84 | 0.85 | 0.82 |
| Gestational age (weeks) | 27.5 (2.5) | 29.8 (2.3) | 29.4 (2.5) | 40.1 (1.2) | <0.001 | <0.001 | <0.001 |
| Birth weight (g) | 997 (261) | 1207 (193) | 1171 (220) | 3653 (481) | <0.001 | <0.001 | <0.001 |
| Birth weight SD score Finnish reference | −0.87 (1.20) | −1.33 (1.69) | −1.24 (1.6) | 0.14 (1.0) | 0.001 | <0.001 | <0.001 |
| Birth weight SD score Norwegian reference | −0.67 (0.90) | −1.09 (1.17) | −1.02 (1.1) | 0.05 (1.0) | 0.002 | <0.001 | <0.001 |
| C-section as a delivery mode | 8 (40.0%) | 66 (70.2%) | 74 (64.9%) | 11 (13.3%) | 0.010 | <0.001 | <0.001 |
| Ventilator treatment (days) | 32.3 (21.5) | 3.3 (4.4) | 8.2 (14.5) | - | - | - | - |
| Supplemental oxygen (days) | 72.7 (84.3) | 11.8 (15.3) | 21.9 (42.8) | - | - | - | - |
| Age at discharge from hospital (days) | 105.9 (82.2) | 61.7 (20.5) | 70.7 (44.2) | - | - | - | - |
| Bronchopulmonary dysplasia diagnosed by clinician | 20 (100%) | - | 20 (25.0%) | - | - | - | - |
| RDS | 18% (90.0%) | 37 (39.8%) | 55 (48.7%) | - | - | - | - |
| Study participant mid-adulthood assessment characteristics | |||||||
| Age (years) | 36.3 (2.7) | 36.1 (3.4) | 36.1 (3.3) | 35.8 (3.3) | 0.48 | 0.24 | 0.36 |
| Height, cm | 164.0 (9.9) | 168.9 (9.5) | 168.0 (9.7) | 173.7 (9.6) | <0.001 | <0.001 | <0.001 |
| BMI (kg/m2) | 27.4 (6.9) | 25.7 (5.66) | 26.0 (5.89) | 25.7 (4.41) | 0.29 | 0.91 | 0.58 |
| Daily smoking | 0 (0) | 13 (14.0%) | 13 (11.5%) | 15 (10.6%) | 0.04 | 0.43 | 0.81 |
| Never smoked vs. others | 14 (70.0%) | 51 (54.8%) | 65 (57.5%) | 71 (50.0%) | 0.09 | 0.47 | 0.23 |
| Current use of inhaled glucocorticoids or adrenergic bronchodilators | 4 (20.0%) | 17 (17.9%) | 21 (12.8%) | 12 (8.5%) | 0.12 | 0.03 | 0.02 |
| History of asthma (treated or diagnosed by a physician) | 4 (20.0%) | 27 (28.4%) | 31 (27.0%) | 30 (21.1%) | 1.0 | 0.20 | 0.28 |
| Respiratory symptoms in the last 12 months | 8 (40.0%) | 32 (34.4%) | 40 (35.4%) | 44 (31.0%) | 0.42 | 0.67 | 0.46 |
| Educational attainment | 0.14 | 0.003 | 0.049 | ||||
| Lower (ISCED levels 1–2) | 0 (0) | 3 (3.2%) | 3 (2.6%) | 2 (1.4%) | |||
| Intermediate (ISCED levels 3–5) | 11 (55%) | 43 (45.3%) | 54 (47.0%) | 47 (33.1%) | |||
| Lower tertiary or higher (ISCED levels 6–8) | 9 (45.0%) | 49 (51.6%) | 58 (50.4%) | 93 (65.5%) |
BPD bronchopulmonary dysplasia, BMI body mass index, HeSVA Helsinki study of very low birth weight adults, ISCED International Standard of Classification of Education, NTNU NTNU low birth weight in a lifetime perspective study, SD standard deviation, VLBW very low birth weight.
aData available only for HeSVA participants.