Table 2 Median (P₂₅–P₇₅)* post-bronchodilator FEV₁, FVC and FEV₁/FVC ratio in the respiratory (R) and non-respiratory (NR) cases stratified by age at inclusion

	All	R cases	NR cases	p Value
All age groups	n = 524	n = 141	n = 383
FEV₁ (% predicted)	93 (78–105)	69 (49–93)	97 (87–107)	<0.001
FVC (% predicted)	92 (80–100)	86 (68–97)	93 (84–101)	<0.001
FEV₁/FVC (%)	80 (68–87)	56 (40–76)	83 (77–89)	<0.001
Age at inclusion <50 years	n = 320	n = 37	n = 283
FEV₁ (% predicted)	98 (90–107)	94 (85–109)	99 (90–107)	0.2
FVC (%predicted)	94 (87–102)	92 (83–102)	95 (88–102)	0.5
FEV₁/FVC (%)	85 (80–89)	83 (77–90)	85 (80–89)	0.2
Age at inclusion >50 years	n = 204	n = 104	n = 100
FEV₁ (% predicted)	77 (54–95)	59 (43–80)	90 (75–105)	<0.001
FVC (%predicted)	83 (69–96)	79 (64–96)	85 (73–96)	<0.050
FEV₁/FVC (%)	63 (50–77)	51 (38–65)	76 (62–82)	<0.001

*Upper and lower quartile values.
FEV₁, forced expiratory volume in 1 s; FVC, forced vital capacity; R, respiratory; NR, non-respiratory.