Table 3– Effects of smoking and lung function on timing of confirmation of asthma

	Subjects n	Visit 1	Visit 2	Visit 3	Visit 4	p-value^#
Smoker	113	25 (22.1)	85 (75.2)	3 (2.7)	0 (0)	0.006
Nonsmoker	233	29 (12.4)	190 (81.5)	7 (3.0)	7 (3.0)	0.006
FEV₁>80% pred	234	16 (6.8)	205 (87.6)	8 (3.4)	5 (2.1)	<0.0001
FEV₁≤80% pred	112	38 (33.9)	70 (62.5)	2 (1.7)	2 (1.7)	<0.0001

Data are presented as n (%), unless otherwise stated. FEV₁: forced expiratory volume in 1 s; % pred: % predicted. ^#: comparison between groups.