Summary of characteristics of the lung cancer cases and control smokers before and after matching
Parameter | Unmatched cohorts | Matched cohorts | p-value# | ||
Control smokers | Lung cancer | Control smokers | Lung cancer | ||
Subjects n | 654 | 446 | 301 | 301 | |
Males % | 57 | 53 | 53 | 53 | |
Age yrs | 59±10 | 69±10 | 64±9 | 65±9 | 0.23 |
Height cm | 170±0.09 | 167±0.08 | 168±0.09 | 168±0.08 | 0.58 |
Weight kg | 80±16 | 69±15 | 78±15 | 71±16 | <0.001 |
Smoking history | |||||
Age started smoking yrs | 18±4 | 17±4 | 18±4 | 18±4 | 0.62 |
Cigarettes·day−1 | 17±9 | 20±10 | 20±7 | 19±9 | 0.33 |
Current smokers % | 24 | 35 | 22 | 39 | <0.001 |
Pack-yrs | 35±20 | 41±25 | 38±18 | 38±18 | 0.93 |
Lung function | |||||
FEV1 L | 2.84±0.82 | 1.86±0.69 | 2.56±0.80 | 1.90±0.69 | <0.001 |
FEV1 % pred | 97±18 | 73±23 | 96±20 | 71±23 | <0.001 |
FEV1/FVC % | 81±9 | 64±13 | 80±10 | 64±13 | <0.001 |
Prevalence of COPD % | |||||
GOLD 1+ | 10 | 60 | 15 | 65 | <0.001 |
GOLD 2+ | 6 | 51 | 8 | 50 | <0.001 |
GOLD 3+ | 1.2 | 14 | 1.3 | 15 | <0.001 |
History of comorbidities % | |||||
Chronic bronchitis | 5 | 18 | 6 | 16 | <0.001 |
Asthma | 12 | 12 | 11 | 13 | 0.45 |
Data are presented as mean±sd, unless otherwise stated. FEV1: forced expiratory volume in 1 s; % pred: % predicted; FVC: forced vital capacity; COPD: chronic obstructive pulmonary disease; GOLD: Global Initiative for Chronic Obstructive Lung Disease. #: comparison for matched cohorts only.