| Study | Subjects | COPD cases | Females | Smoking status never/former/current | Age years | |||
| Overall | Cases | Controls | Difference | |||||
| ERF | 2580 | 41 (1.6) | 1468 (56.9) | 981/691/908 | 49.80±15.67 | 51.14±13.35 | 49.78±15.71 | 1.36 |
| EX-ATHLETES | 577 | 44 (7.6) | 0 (0) | 361/177/39 | 72.68±5.92 | 73.23±5.98 | 72.63±5.92 | 0.60 |
| FITSA | 423 | 33 (7.8) | 423 (100) | 369/32/21 | 68.61±3.41 | 68.27±3.48 | 68.64±3.41 | −0.37 |
| GRAPHIC | 2007 | 76 (3.8) | 994 (49.5) | 1109/491/407 | 39.31±14.50 | 37.09±14.20 | 39.38±14.51 | −2.29 |
| KORA Age | 868 | 51 (5.9) | 435 (50.1) | 494/332/42 | 75.65±6.34 | 76.02±6.10 | 75.63±6.36 | 0.39 |
| KORA F3 | 2532 | 191 (7.5) | 1314 (51.9) | 1133/863/536 | 53.62±10.80 | 55.77±9.85 | 53.44±10.86 | 2.33 |
| KORA F4 | 2797 | 231 (8.3) | 1477 (52.8) | 1228/1045/524 | 54.90±12.85 | 54.15±12.75 | 54.97±12.85 | −0.82 |
| NAG-FIN | 1718 | 97 (5.6) | 782 (45.5) | 204/804/710 | 55.89±7.63 | 59.72±9.07 | 55.67±7.48 | 4.05 |
| NFBC 1966 | 4843 | 434 (9.0) | 2516 (52.0) | 2463/590/1790 | 31.0±0.2 | 31.0±0.2 | 31.0±0.2 | 0 |
| NTR | 7529 | 906 (12.0) | 4688 (62.3) | 3734/2213/1582 | 42.50±15.29 | 41.51±14.80 | 42.64±15.35 | −1.13 |
| QIMR | 315 | 149 (47.3) | 161 (51.1) | NA | 20.94±5.48 | 20.60±5.40 | 21.25±5.56 | −0.65 |
| TwinGene | 597 | 50 (8.4) | 597 (100) | 358/239# | 71.72±5.89 | 71.69±7.56 | 71.73±5.73 | −0.04 |
| TwinsUK | 4243 | 531(12.5) | 3869 (91.2) | 3003/784/456 | 51.07±13.39 | 49.09±14.20 | 51.37±13.25 | −2.28 |
| Total | 31 029 | 2834 (9.1) | 18 724 (60.3) | −0.27¶ | ||||
Data are presented as n, n (%) or mean±sd, unless otherwise stated. ERF: Erasmus Rucphen Family; FITSA: Finnish Twin Study on Ageing; KORA: Cooperative Health Research in the Region Augsburg; NAG-FIN: Nicotine Addiction Genetics Finland; NFBC: Northern Finland Birth Cohort Study; NTR: Netherlands Twin Register; QIMR: Queensland Institute of Medical Research; NA: not available. #: current smoking no/yes; ¶: mean age difference between cases and controls, weighted by total sample size.