Demographic data, asbestos exposure, and multivariate analysis of lung functional parameters according to CT scan abnormalities
| Group 1 | Group 0 | Group 2 | p Value¶ | p Value | |
| Pleural plaques* | Normal CT scan† | Diffuse pleural thickening‡ | Group 1/Group 0 | Group 0/Group 2 | |
| Number of subjects | 526 | 1802 | 41 | ||
| Gender | 0.0008 | 0.12 | |||
| Male, n (%) | 515 (97.9) | 1700 (94.3) | 41 (100) | ||
| Female, n (%) | 11 (2.1) | 102 (5.7) | – | ||
| Mean (SD¶) age (years) | 64.8 (5.5) | 62.3 (5.3) | 65.9 (6.8) | <0.0001 | <0.0001 |
| Smoking status | <0.0001 | 0.25 | |||
| Non-smokers, n (%) | 81 (15.4) | 548 (30.4) | 8 (19.5) | ||
| Ex-smokers, n (%) | 403 (76.6) | 1145 (63.5) | 29 (70.7) | ||
| Smokers, n (%) | 42 (8.0) | 109 (6.0) | 4 (9.8) | ||
| Mean (SD) BMI, kg/m2 | 27.4 (3.9) | 27.4 (3.7) | 27.4 (3.9) | 0.9705 | 1.00 |
| Duration of exposure to asbestos (years) | 0.0059 | 0.26 | |||
| 1–9, n (%) | 23 (4.4) | 111 (6.2) | 2 (4.9) | ||
| 10–19, n (%) | 40 (7.6) | 202 (11.2) | 2 (4.9) | ||
| 20–29, n (%) | 89 (16.9) | 365 (20.3) | 7 (17.1) | ||
| 30–39, n (%) | 251 (47.7) | 752 (41.7) | 16 (39.0) | ||
| ≥40, n (%) | 123 (23.4) | 372 (20.6) | 14 (34.1) | ||
| Cumulative exposure index to asbestos (unit of exposure × years) | <0.0001 | 0.14 | |||
| 0–3.4, n (%) | 66 (12.5) | 461 (25.6) | 6 (14.6) | ||
| 3.4–17.2, n (%) | 65 (12.4) | 385 (21.4) | 7 (17.1) | ||
| 17.2–33.1, n (%) | 85 (16.2) | 365 (20.3) | 9 (21.9) | ||
| 33.1–91.9, n (%) | 110 (20.9) | 338 (18.8) | 8 (19.5) | ||
| ≥ 91.9, n (%) | 200 (38.0) | 253 (14.0) | 11 (26.8) | ||
| Mean (SD) | 110.9 (126.1) | 47.9 (83.1) | 81.3 (112.0) | ||
| Median | 40.0 | 20.0 | 30.0 | ||
| Pulmonary function (% predicted FVC, FEV1, FEF25-75, RV and TLC, absolute ratio for FEV1/FVC)§ | |||||
| FVC, mean (SD) | 96.4 (17.3) | 100.4 (16.6) | 87.7 (20.5) | <0.0001 | <0.0001 |
| FEV1, mean (SD) | 96.9 (20.3) | 101.9 (19.2) | 85.8 (20.9) | <0.001 | <0.0001 |
| FEV1/FVC, mean (SD) | 78.4 (9.3) | 80.0 (7.9) | 76.1 (7.2) | 0.87 | 0.04 |
| FEF25-75, mean (SD) | 88.9 (36.7) | 95.9 (35.5) | 75.9 (35.0) | 0.08 | 0.0019 |
| FEF25, mean (SD) | 84.3 (51.9) | 92.4 (60.5) | 73.8 (56.2) | 0.06 | 0.06 |
| FEF50, mean (SD) | 88.7 (45.4) | 93.9 (34.2) | 69.6 (34.0) | 0.31 | <0.0001 |
| FEF75, mean (SD) | 86.0 (29.8) | 91.8 (28.7) | 74.8 (26.7) | 0.04 | 0.001 |
| RV, mean (SD) | 108.0 (31.1) | 109.1 (35.4) | 91.9 (31.9) | 0.97 | 0.0056 |
| TLC, mean (SD) | 98.4 (14.1) | 101.2 (16.0) | 88.4 (16.6) | 0.03 | <0.0001 |
↵* Subjects with isolated pleural plaques and subjects with pleural plaques and other abnormalities (except asbestosis and diffuse pleural thickening).
↵† Subjects with no CT scan abnormalities.
↵‡ Subjects with diffuse pleural thickening and other abnormalities (except asbestosis).
↵§ Adjusting for age, smoking status, BMI, cumulative exposure index (CEI) for asbestos and the centres where pulmonary function tests were conducted.
↵¶ χ2 or Fisher tests.
BMI, body mass index; FEF25-75, forced expiratory flow at 25–75% FVC; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; RV, residual volume; TLC, total lung capacity.