Table 2– Main characteristics of the two study groups

	All	Intervention	Control	p-value
Subjects n	4581	3383	1198
Males %	55.7	55.2	56.8	0.335
Age yrs	53.6±18.9	54.5±18.0	51.1±21.0	<0.001
Height cm	163.2±10.5	163.5±10.0	162.2±11.7	0.030
FEV₁ % pred	78.5±22.8	78.5±22.9	78.3±22.4	0.784
FVC % pred	83.5±19.6	83.8±19.6	82.5±19.3	0.037
FEV₁/FVC %	71.6±13.1	71.2±13.3	72.6±12.6	0.001

Data are presented as mean±sd, unless otherwise stated. FEV₁: forced expiratory volume in 1 s; % pred: % predicted; FVC: forced vital capacity. Bold indicates statistically significant p-values.