. Author manuscript; available in PMC: 2021 Jun 10.

Published in final edited form as: Thorax. 2010 Jun;65(6):480–485. doi: 10.1136/thx.2009.122002

Table 3.

The association between gender and FEV₁% predicted in subjects with chronic obstructive pulmonary disease (COPD), with regression coefficients (β) and p values for female gender and for the interaction between gender and smoking

		Gender^*		Gender×pack-years^†
	n^‡	β (95% CI)	p Value	β (95% CI)	p Value
All subjects with COPD	948	−0.2 (−2.5 to 2.1)	0.865	0.2 (0.02 to 0.3)	0.027
Early onset, age <60	315	−3.8 (−7.6 to 0.1)	0.057	0.3 (0.1 to 0.6)	0.014
Low exposure, <20 pack-years	239	−5.7 (−10.2 to −1.3)	0.012	0.8 (−0.1 to 1.8)	0.066

Basic model with no interaction term, adjusted for pack-years, self-reported asthma and educational level.

^†

Gender×pack-years interaction terms are included in the basic models.

^‡

Educational level was missing for five subjects with COPD; asthma history was missing for one subject with COPD.

FEV₁, forced expiratory volume in 1 s.