TABLE 1

Characteristics and prevalence of bronchodilator reversibility

	No airway disease (controls)	Current asthma	*p-value versus* controls**	COPD	*p-value versus* controls**	*p-value asthma versus* COPD**
Subjects n	31 649	2833		1146
Characteristics
Female	53.0	63.1	<0.0001	26.4	<0.0001	<0.0001
Age years	54±11	53±12	<0.0001	60±11	<0.0001	<0.0001
Smoking history			<0.0001		<0.0001	<0.0001
Never-smoker	61.2	54.6		0
Ex-smoker	21.8	30.4		40.9
Current smoker	17.0	15.1		59.1
BMI kg·m⁻²			<0.0001		<0.0001	<0.0001
<20	8.3	5.3		14.8
20–25	33.6	29.6		37.4
>25–30	35.3	32.2		32.8
>30	22.8	32.9		15.0
Pre-bronchodilator FEV₁ % pred	87±18	78±21	<0.0001	65±20	<0.0001	<0.0001
Pre-bronchodilator FVC % pred	90±18	88±18	<0.0001	87±20	<0.0001	0.58
Pre-bronchodilator FEV₁/FVC %	77±7	69±13	<0.0001	57±10	<0.0001	<0.0001
Post-bronchodilator FEV₁ % pred	89±18	82±21	<0.0001	69±20	<0.0001	<0.0001
Post-bronchodilator FVC % pred	90±18	90±18	>0.99	92±20	0.001	0.001
Post-bronchodilator FEV₁/FVC %	79±7	73±12	<0.0001	58±9	<0.0001	<0.0001
Flow response
ΔFEV₁ ≥12% from baseline	5.9	20.2	<0.0001	24.5	<0.0001	<0.0001
ΔFEV₁ ≥10% pred	8.9	25.8	<0.0001	29.8	<0.0001	0.10
ΔFEV₁ ≥12% and 200 mL from baseline	5.1	17.3	<0.0001	18.4	<0.0001	0.39
Volume response
ΔFVC ≥10.5% from baseline	5.3	15.8	<0.0001	25.2	<0.0001	<0.0001
ΔFVC ≥9.2% pred	10.7	22.8	<0.0001	31.6	<0.0001	<0.0001
ΔFVC ≥10.5% and 320 mL from baseline	3.6	11.8	<0.0001	21.6	<0.0001	<0.0001

Data are presented as % or mean±sd, unless otherwise stated. COPD: chronic obstructive pulmonary disease; BMI: body mass index; FEV₁: forced expiratory volume in 1 s; FVC: forced vital capacity.