Characteristic | Engineers/brakemen | Unexposed | Total |
Whole cohort | |||
n | 21 234 | 9437 | 30 671 |
Mean (SD) | |||
Age at hire | 31.4 (5.5) | 32.7 (5.9) | 31.8 (5.6) |
Age in 1959 | 47.8 (5.4) | 48.7 (5.7) | 48.1 (5.5) |
Pack–years* | 43.3 (4.1) | 40.9 (3.7) | 42.1 (4.1) |
Cigarette smoking (%)† | |||
Never | 2739 (12.9) | 1680 (17.8) | 4419 (14.4) |
Current | 16 329 (76.9) | 6587 (69.8) | 22 916 (74.7) |
Former | 2166 (10.2) | 1170 (12.4) | 3336 (10.9) |
COPD deaths | 1219 | 464 | 1683 |
Hired <1945 | |||
n | 17 321 | 6785 | 24 106 |
Mean (SD) | |||
Age at hire | 31.1 (5.5) | 31.9 (5.8) | 31.3 (5.6) |
Age in 1959 | 48.1 (5.4) | 49.2 (5.7) | 48.4 (5.5) |
Pack–years* | 43.3 (4.1) | 40.8 (3.8) | 42.1 (4.1) |
Cigarette smoking (%)† | |||
Never | 12.9 | 17.5 | 15.2 |
Current | 76.8 | 70.0 | 77.4 |
Former | 10.3 | 12.5 | 11.4 |
COPD deaths | 1002 | 349 | 1351 |
Hired ⩾1945 | |||
n | 3913 | 2652 | 6565 |
Mean (SD) | |||
Age at hire | 32.9 (5.1) | 34.5 (5.7) | 33.5 (5.5) |
Age in 1959 | 46.4 (5.2) | 47.4 (5.6) | 46.8 (5.4) |
Pack–years* | 43.1 (4.6) | 40.9 (3.8) | 42.0 (4.3) |
Cigarette smoking (%)† | |||
Never | 12.9 | 18.4 | 15.7 |
Current | 77.1 | 69.3 | 73.2 |
Former | 10.0 | 12.3 | 11.1 |
COPD deaths | 217 | 115 | 332 |
*Average of five smoking imputations among ever-smokers.
†Average of five smoking imputations.
COPD, chronic obstructive pulmonary disease.