1.

两组患者吸烟情况的比较[n (%)]

Comparison of smoking index between the two groups of patients [n (%)]

Group	Number of smokers			Smoking index (branch/year)
	Yes	No		≥400	< 400
Smoking is less than 3 years for smoking cessation or smoking ≥1/day and for ≥1 year. COPD: chronic obstructive pulmonary disease.
COPD with bronchopulmonary carcinoma (n=118)	65(55.1)	53 (44.9)		59 (90.8)	6 (9.2)
Simple COPD (n=120)	25(20.8)	95 (79.2)		12 (48.0)	13 (52.0)
X2	27.34			16.64
P	< 0.01			< 0.01