Study participants' characteristics.
| Nonsmokers | Former smokers | Current smokers | p-value | |
| Males/females | 29/35 | 40/28 | 22/24 | |
| Age years | 45 (18–80) | 59 (23–83)# | 47 (19–73) | 0.0091 |
| Height cm | 172 (156–194) | 174 (139–194) | 176 (160–205) | 0.6208 |
| Weight kg | 75 (51–125) | 80 (50–135) | 74 (50–120) | 0.3674 |
| Smoking intensity pack-years | 15.0 (0.2–96)¶ | 23 (0.3–82) | 0.0258 | |
| Z-scores | ||||
| FEV1 | 0.22 (−2.08–3.35) | −0.07 (−3.37–3.32) | −0.92 (−4.3–2.02)+ | <0.0001 |
| FVC | −0.10 (−2.8–2.69) | −0.05 (−3.49–3.05) | −0.45 (−3.19–2.26) | 0.0449 |
| FEV1/FVC | 0.34 (−2.06–3.42) | −0.06 (−2.56–1.84) | −0.64 (−4.08–1.71)§ | <0.0001 |
Data are presented as median (range) unless otherwise stated. FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity. #: significant difference between former smokers and nonsmokers and current smokers; ¶: significant differences between former and current smokers; +: significant differences between current smokers and former smokers and nonsmokers; §: significant differences among current and former smokers and nonsmokers.