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
| n‡ | Gender* | Gender×pack-years† | |||
| 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.