Table 1.

Prevalence of bronchial obstruction according to different classification systems, by age

	Age 65 - 74 years N (%)	Age ≥ 75 years N (%)
ATS/ERS
No obstruction	451 (61.8)	245 (57.1)
Mild obstruction	137 (18.8)	93 (21.7)
Moderate/severe obstruction	142 (19.4)	91 (21.1)
BTS
No obstruction	527 (72.2)	302 (70.4)
Mild obstruction	135 (18.5)	96 (22.4)
Moderate/severe obstruction	68 (9.3)	31 (7.2)
GOLD
No obstruction	448 (61.4)	206 (48.0)
Mild obstruction	79 (10.8)	96 (22.4)
Moderate/severe obstruction	203 (27.8)	127 (29.6)