Table 1

Description of the study population.

Variable
Fast decline (n = 275)
No decline (n = 304)
p Value*

Age, yr†
49.5 (6.4)
47.6 (6.9)
0.0007
Sex, n (%)
163 men (59)
203 men (67)
0.06
Smoking history, pk yrs†‡
43.3 (19.1)
38.3 (18.1)
0.0005
Baseline FEV1, % predicted†§
72.7 (8.9)
75.7 (8.1)
<0.0001
Methacholine response†ll
-23.4 (32.7)
-7.5 (14.0)
<0.0001

* p Values derived from Wilcoxon test or chi-square analysis.

† Mean (SD).

‡ Number of packs of cigarettes smoked per day × number of years of smoking.

§ Lung function at the start of the study as measured percent predicted FEV1 (postbronchodilator).

ll Measurement of the responsiveness of the airways to methacholine expressed as percent decline in FEV1 per final cumulative dose of methacholine administered[36] Methacholine response is strongly associated with rate of decline in lung function[37,38]

Wallace et al. Respiratory Research 2006 7:76   doi:10.1186/1465-9921-7-76