Table 2 Basic demographic characteristics of the study cohort (n = 1730) and of non‐study cohort who were in survey 1 (n = 7309), US, National Study of Coal Workers' Pneumoconiosis, 1969–97.
| Characteristic | Cohort | Non‐study cohort | |||
|---|---|---|---|---|---|
| Alive | Dead | n (%) | |||
| n, % | 1,445 | 83.5 | 285 | 16.5 | 7309* (100) |
| Initial age (years) (mean, SD) | 41.6 | 6.6 | 46.1 | 6.4 | 45.5 (12.9) |
| Person‐years of mortality follow‐up (mean, SD) | 13.5 | 3.7 | 7.14 | 4.3 | 21.2† (7.7)† |
| Initial BMI (mean, SD) | 25.9 | 3.4 | 26.2 | 3.8 | 25.9 (3.8) |
| Change in weight (kg/year) (mean, SD) | 0.36 | 0.61 | 0.19 | 0.6 | NA |
| Pack‐years (mean, SD) | 19.2 | 18.9 | 22.6 | 18.9 | 17.8 (18.1) |
| Initial FEV1 (l) (mean, SD) | 3.8 | 0.6 | 3.5 | 0.6 | 3.5 (0.8) |
| Obstructive/restrictive patterns at first survey | |||||
| Obstructive pattern only (n, %) | 239 | 16.5 | 51 | 17.9 | 1267 (17.3) |
| Restrictive pattern only (n, %) | 150 | 10.3 | 48 | 16.8 | 765 (10.5) |
| Both obstructive and restrictive pattern (n, %) | 31 | 2.1 | 13 | 4.6 | 1124 (15.4) |
| FEV1 rate of decline (ml/year) (mean, SD) | 43.5 | 31.5 | 53.6 | 39.0 | NA |
| Years between PFT (mean, SD) | 13.2 | 3.6 | 10.9 | 3.6 | NA |
| Smoking status | |||||
| Current smoker (n, %) | 487 | 33.7 | 145 | 50.9 | 3966 (54.3) |
| Never smoked (n, %) | 284 | 19.7 | 43 | 15.1 | 1470 (20.1) |
| Former smoker (n, %) | 607 | 42.0 | 82 | 28.8 | 1873 (25.6) |
| Indeterminate smoker (n, %) | 67 | 4.6 | 15 | 5.2 | NA |
BMI, body mass index; FEV1, forced expiratory volume in one second; PFT, NA, not available; PFT, pulmonary function test.
*Dead (2971, 40.7%).
†Calculated from survey 1.