Table 3

Lung function in term and very preterm-born adolescents and young adults

	Term controls (reference)	Preterm	Preterm
	Term controls (reference)	Preterm	No-BPD	BPD
Forced flows and volumes (spirometry)
n successful	40	121	43	78
FEV₁ z-score	−0.03 (1.14)	−0.88 (1.16)*	−0.48 (1.10)	−1.10 (1.14)*†
FEV1 z-score post-BD	0.34 (1.12)	−0.28 (1.02)*	0.00 (1.07)	−0.43 (0.97)*
n successful	38	113	41	72
FVC z-score	0.09 (1.07)	−0.01 (1.02)	0.21 (1.03)	−0.14 (1.01)
FEV₁/FVC z-score	−0.19 (1.08)	−1.17 (1.12)*	−0.99 (1.14)*	−1.27 (1.10)*
FEF_25-75 z-score	−0.27 (1.11)	−1.29 (1.15)*	−0.98 (1.15)*	−1.47 (1.13)*
Bronchodilator assessment, n	39	119	42	77
No with BDR	3 (7.7%)	31 (26.1%)*	7 (16.7%)	24 (31.2%)*
Gas exchange (DLCO)
n successful	41	120	45	75
DLCO z-score	1.48 (0.97)	0.85 (1.08)*	1.06 (1.11)	0.73 (1.05)*
VA z-score	0.74 (0.88)	0.64 (1.18)	0.71 (1.15)	0.60 (1.20)
KCO z-score	0.89 (0.85)	0.33 (1.01)*	0.49 (1.07)	0.24 (0.97)*
Lung volumes (whole body plethysmography)
n successful	40	123	44	79
TLC z-score	0.27 (0.70)	0.28 (0.82)	0.34 (0.81)	0.25 (0.83)
FRC z-score	0.42 (0.69)	0.55 (0.92)	0.42 (0.89)	0.62 (0.93)
RV z-score	0.47 (0.53)	0.69 (0.79)	0.51 (0.74)	0.79 (0.81)*
RV/TLC (%) z-score	0.50 (0.73)	0.77 (0.93)	0.52 (0.85)	0.91 (0.95)*
Respiratory system mechanics (oscillometry)
n successful	41	125	45	80
Rrs₅ z-score	1.25 (0.87)	1.33 (1.18)	1.20 (1.46)	1.40 (0.98)
Fres z-score	1.13 (1.04)	1.90 (1.42)*	1.42 (1.42)	2.17 (1.36)*†
AX z-score	1.25 (0.85)	1.92 (1.15)*	1.61 (1.23)	2.10 (1.08)*†
Xrs₅ z-score	0.75 (0.92)	1.36 (1.49)*	1.04 (1.41)	1.54 (1.51)*
Rrs_5-20 (cmH₂O.s/L)	0.10 (0.34)	0.51 (0.81)*	0.40 (0.77)	0.57 (0.83)*
Median (IQR)
Airway Inflammation
n successful	41	125	45	80
FeNO (ppm)	19 (12, 25)	15 (10, 26)	19 (12, 32)	13 (10, 19)†
Ventilation distribution (multiple breath wash-out)
n successful	36	97	40	57*
LCI	6.54 (5.99, 7.19)	7.26 (6.46, 8.19)*	7.14 (5.96, 7.79)	7.39 (6.63, 8.49)*
MR1 (M1/M0)	1.79 (1.50, 1.97)	1.94 (1.57, 2.19)*	1.94 (1.52, 2.15)	1.94 (1.61, 2.34)*
MR2 (M2/M0)	5.68 (4.16, 6.98)	6.92 (4.59, 8.85)*	6.90 (4.14, 8.57)	7.02 (4.70, 10.11)*
Airway resistance (plethysmography)
n successful	40	119	43	76
sGaw (1 /s*cmH₂0)	0.20 (0.17, 0.25)	0.15 (0.11, 0.23)*	0.17 (0.11, 0.25)	0.15 (0.11, 0.20)*

Data are presented as mean (SD) unless otherwise indicated, except for the number of successful tests. The ‘preterm’ group is composed of all preterm participants, recruited using a deliberate 1 preterm without BPD: 2 preterm with BPD strategy.
Bold font indicates statistical significance.
*p<0.05 compared with term-born group.
†p<0.05 compared with no-BPD group.
AX, area under the reactance curve; BD, bronchodilator; BDR, bronchodilator response; BPD, bronchopulmonary dysplasia; DLCO, diffusing capacity of the lung for carbon monoxide; FEF_25–75, forced expiratory flow at 25%–75% of the pulmonary volume; FeNO, fractional exhaled nitric oxide; FEV₁, forced expiratory volume in 1 s; FRC, functional residual capacity; Fres, resonant frequency; FVC, forced vital capacity; KCO, carbon monoxide transfer coefficient; LCI, Lung Clearance Index; MR1/2, moment ratio 1/2; Rrs_5-20, difference in respiratory system resistance between 20 and 5 Hz; RV, residual volume; sGaw, specific airway conductance; TLC, total lung capacity; VA, alveolar volume; Xrs₅, respiratory system reactance at 5 Hz.