Table 3.

Spirometric lung function data comparing term-born with extremely preterm subjects (n=286 subjects)

	82–85 cohort*									91–92 cohort									99–00 cohort
Age (mean, range)	17.7 (15.3–19.9)			24.9 (22.5–27.0)			34.5 (32.1–37.6)			10.6 (9.7–11.5)			17.8 (17.0–19.2)			27.1 (26.1–28.4)			11.6 (10.1–13.8)				19.8 (18.2–21.4)
n/eligble
Term-born	46/46			40/46			34/46			35/35			28/35			26/34			54/57				43/57
EP no BPD	34/38			32–33/38			25–26/36			23/23			19/23			15/23			26/43				27/43
EP BPD	12/13			12/13			9–10/12			12/12			12/12			9/12			32/45				23/45
	Mean	95% CI	P value	Mean	95% CI	P value	Mean	95% CI	P value	Mean	95% CI	P value	Mean	95% CI	P value	Mean	95% CI	P value	Mean	95% CI	P value	Mean	95% CI	P value
FEV1 z-score
Term-born (ref)	0.0	−0.3 to 0.3	−	−0.1	−0.4 to 0.2	−	0.1	−0.2 to 0.4	−	−0.1	−0.4 to 0.3	−	−0.2	−0.6 to 0.1	−	0.1	−0.2 to 0.5	−	−0.3	−0.6 to −0.1	−	−0.1	−0.4 to 0.2	−
EP no BPD	−1.1	−1.5 to −0.8	<0.001	−0.9	−1.2 to −0.6	<0.001	−0.9	−1.2 to −0.5	<0.001	−0.6	−1.0 to −0.1	0.07	−0.6	−1.1 to −0.2	0.17	−0.4	−0.8 to 0.1	0.08	−0.6	−0.9 to −0.2	0.33	−0.5	−0.9 to −0.2	0.07
EP BPD	−1.5	−2.1 to −1.0	<0.001	−1.4	−1.9 to −0.8	<0.001	−1.6	−2.2 to −1.0	<0.001	−1.5	−2.1 to −0.9	<0.001	−1.4	−2.0 to −0.9	<0.001	−1.5	−2.1 to −0.9	<0.001	−0.7	−1.1 to −0.4	0.08	−0.6	−1.0 to −0.3	0.03
FVC z-score
Term-born (ref)	−0.2	−0.5 to 0.1	−	0.0	−0.3 to 0.3	−	0.2	−0.2 to 0.5	−	−0.1	−0.5 to 0.2	−	−0.2	−0.6 to 0.2	−	0.4	0.1 to 0.8	−	−0.2	−0.4 to 0.1	−	0.0	−0.3 to 0.3	−
EP no BPD	−0.9	−1.3 to −0.6	0.003	−0.4	−0.7 to 0.0	0.11	−0.3	−0.7 to 0.0	0.05	−0.5	−1.0 to −0.1	0.17	−0.4	−0.9 to 0.0	0.41	−0.1	−0.5 to 0.4	0.07	−0.1	−0.5 to 0.3	0.67	−0.1	−0.5 to 0.3	0.66
EP BPD	−1.1	−1.6 to −0.5	0.01	−0.6	−1.2 to 0.0	0.07	−0.9	−1.5 to −0.3	0.002	−0.7	−1.2 to −0.1	0.15	−0.2	−0.8 to 0.4	0.95	−0.1	−0.7 to 0.5	0.12	−0.2	−0.5 to 0.2	0.96	−0.3	−0.7 to 0.1	0.20
FEV1/FVC z-score
Term-born (ref)	0.4	0.1 to 0.6	−	−0.2	−0.4 to 0.1	−	−0.2	−0.5 to 0.1	−	0.1	−0.2 to 0.4	−	−0.1	−0.5 to 0.2	−	−0.5	−0.9 to −0.2	−	−0.3	−0.6 to 0.0	−	−0.2	−0.5 to 0.0	−
EP no BPD	−0.3	−0.7 to 0.0	0.002	−0.9	−1.3 to −0.6	<0.001	−0.9	−1.3 to −0.5	0.004	0.0	−0.4 to 0.4	0.73	−0.3	−0.7 to 0.2	0.55	−0.5	−1.0 to −0.1	0.96	−0.8	−1.2 to −0.4	0.03	−0.7	−1.1 to −0.3	0.06
EP BPD	−0.7	−1.2 to −0.1	0.001	−1.0	−1.6 to −0.5	0.007	−1.2	−1.8 to −0.6	0.003	−1.4	−2.0 to −0.8	<0.001	−1.7	−2.3 to −1.2	<0.001	−1.9	−2.5 to −1.3	<0.001	−0.9	−1.2 to −0.6	0.008	−0.5	−0.9 to −0.1	0.30
FEF 25–75% z-score
Term-born (ref)	0.2	−0.1 to 0.5	−	−0.1	−0.4 to 0.2	−	−0.1	−0.4 to 0.2	−	−0.2	−0.6 to 0.1	−	−0.3	−0.7 to 0.0	−	−0.4	−0.8 to −0.1	−	−0.6	−0.8 to −0.3	−	−0.3	−0.5 to 0.0	−
EP no BPD	−1.0	−1.3 to −0.7	<0.001	−1.2	−1.6 to −0.9	<0.001	−1.1	−1.5 to −0.8	<0.001	−0.8	−1.2 to −0.4	0.05	−0.6	−1.0 to −0.2	0.32	−0.7	−1.1 to −0.2	0.35	−1.0	−1.3 to −0.6	0.06	−0.8	−1.2 to −0.4	0.02
EP BPD	−1.5	−2.0 to −0.9	<0.001	−1.5	−2.0 to −0.9	<0.001	−1.6	−2.2 to −1.1	<0.001	−1.9	−2.5 to −1.4	<0.001	−1.9	−2.5 to −1.4	<0.001	−2.1	−2.7 to −1.5	<0.001	−1.2	−1.6 to −0.9	0.003	−0.9	−1.3 to −0.5	0.007

All results are based on longitudinal mixed-effects models. The p values compare EP subjects with controls.

*Two of the eligible non-participants could not be classified according to BPD status, but are presented in the non-BPD group.

BPD, bronchopulmonary dysplasia (supplemental oxygen or respiratory support at postmenstrual age ≥36 weeks); EP, subjects born extremely preterm or with extremely low birth weight (gestational age ≤28 weeks or birth weight ≤1000 g); FEF_25–75%, forced expiratory flow at 25%–75% of FVC; FEV₁, forced expiratory volume in 1 s; FVC, forced vital capacity; ref, reference level.