Table 4

Multivariable associations between doctor-diagnosed childhood pneumonia-pleurisy, FEV₁ and measures of spirometric restriction from childhood to middle age

Episodes of pneumonia/pleurisy†	Complete case (n)	Measures of spirometric restriction at ages 7, 45 and 53 years‡§¶
		FVC		FVC <LLN without post-BD AO
		(z-score (SD, 95% CI))	P value	OR (95% CI)	P value
At age 7
0	5390	Ref		Ref
≥1	852	+0.01 (−0.1 to +0.1)	0.623	0.92 (0.6 to 1.3)	0.630
1–2	767	+0.03 (−0.04 to +0.1)	0.419	0.87 (0.6 to 1.3)	0.487
>2	85	−0.14 (−0 to .3 to +0.1)	0.149	1.31 (0.5 to 3.3)	0.560
At age 45
0	984	Ref		Ref
≥1	210	−0.16 (−0.3 to 0.02)*	0.028	3.02 (1.5 to 6.0)**	0.002
1–2	189	−0.14 (−0.3 to 0.03)	0.069	2.88 (1.4 to 5.9)**	0.004
>2	21	−0.36 (−0.7 to +0.05)	0.091	4.50 (0.94 to 21)	0.058
At age 53
0	2064	Ref		Ref
≥1	312	−0.12 (−0.2 to 0.01)*	0.044	1.76 (0.9 to 3.5)	0.104
1–2	287	−0.10 (−0.2 to +0.01)	0.735	1.57 (0.8 to 3.3)	0.236
>2	25	−0.22 (−0.6 to +0.1)	0.213	3.91 (0.9 to 18)	0.076

*P<0.05, **p<0.01, ***p<0.001.
†≥1 and >2 episodes refer to childhood pneumonia/pleurisy-ever and recurrent pneumonia/pleurisy in the main text, respectively.
‡Spirometric restriction was defined by FVC <LLN in the absence of post-BD AO (FEV₁:FVC ≥LLN).
§Multivariable adjustments include sampling weights (at age 45), maternal/paternal smoking, socioeconomic status (paternal occupation, rurality of primary school) and history of breast/bottle feeding.
¶If a statistical interaction is present, stratified results have been presented in the main text and correspond to online supplementary table E5 (by current childhood asthma), online supplementary table E6 (by participant sex) and online supplementary table E7 (by never/ever smoking).
FEV₁:FVC, the ratio between FEV₁ and FVC; LLN, lower limit of normal; post-BD AO, postbronchodilator airflow obstruction; Ref, reference.