Group 1A | Group 1B | Group 0 | p Value¶ | p Value | |
Isolated pleural plaques* | Pleural plaques and other abnormalities† | Normal CT scan‡ | Group 1A/Group0 | Group 1B/Group 0 | |
Number of subjects | 403 | 123 | 1802 | ||
Gender | 0.0005 | 0.45 | |||
Male, n (%) | 397 (98.5) | 118 (95.9) | 1700 (94.3) | ||
Female, n (%) | 6 (1.5) | 5 (4.1) | 102 (5.7) | ||
Mean (SD) age, years | 64.6 (5.4) | 65.2 (5.8) | 62.3 (5.3) | <0.0001 | <0.0001 |
Smoking status | <0.0001 | <0.0001 | |||
Non-smokers, n (%) | 66 (16.4) | 15 (12.2) | 548 (30.4) | ||
Ex-smokers, n (%) | 311 (77.2) | 92 (74.8) | 1145 (63.5) | ||
Smokers, n (%) | 26 (6.4) | 16 (13.0) | 109 (6.0) | ||
Mean (SD) BMI, kg/m2 | 27.7 (3.8) | 26.1 (3.8) | 27.4 (3.7) | 0.06 | 0.0004 |
Mean (SD) duration of exposure to asbestos (years) | 0.02 | 0.33 | |||
1–9, n (%) | 17 (4.2) | 6 (4.9) | 111 (6.2) | ||
10–19, n (%) | 33 (8.2) | 7 (5.7) | 202 (11.2) | ||
20–29, n (%) | 65 (16.1) | 24 (19.5) | 365 (20.3) | ||
30–39, n (%) | 193 (47.9) | 58 (47.1) | 752 (41.7) | ||
≥40, n (%) | 95 (23.6) | 28 (22.8) | 372 (20.6) | ||
Cumulative exposure index to asbestos (unit of exposure × years) | <0.0001 | <0.0001 | |||
0–3.4 | 46 (11.4) | 20 (16.3) | 461 (25.6) | ||
3.4–17.2 | 54 (13.4) | 11 (8.9) | 385 (21.4) | ||
17.2–33.1 | 71 (17.6) | 14 (11.4) | 365 (20.3) | ||
33.1–91.9 | 79 (19.6) | 31 (25.2) | 338 (18.8) | ||
≥91.9 | 153 (38.0) | 47 (38.2) | 253 (14.0) | ||
Mean (SD) | 112.6 (128.6) | 107.3 (118.2) | 47.9 (83.1) | ||
Median | 39.0 | 42.0 | 20.0 | ||
Pulmonary function (% predicted FVC, FEV1, FEF25-75, RV and TLC, absolute ratio for FEV1/FVC)§ | |||||
FVC, mean (SD) | 96.6 (16.6) | 95.9 (19.6) | 100.4 (16.6) | <0.0001 | 0.0004 |
FEV1, mean (SD) | 97.9 (19.4) | 93.5 (22.9) | 101.9 (19.2) | 0.0032 | <0.0001 |
FEV1/FVC, mean (SD) | 79.2 (9.0) | 75.9 (9.8) | 80.0 (7.9) | 0.27 | 0.0025 |
FEF25-75, mean (SD) | 91.8 (36.2) | 79.5 (37.1) | 95.9 (35.5) | 0.53 | 0.0005 |
FEF25, mean (SD) | 88.5 (53.7) | 70.9 (43.3) | 92.4 (60.5) | 0.50 | 0.0006 |
FEF50, mean (SD) | 89.3 (34.5) | 86.5 (70.1) | 93.9 (34.2) | 0.42 | 0.32 |
FEF75, mean (SD) | 87.5 (29.4) | 81.1 (30.6) | 91.8 (28.7) | 0.20 | 0.009 |
RV, mean (SD) | 106.5 (28.9) | 112.6 (36.7) | 109.1 (35.4) | 0.8838 | 0.30 |
TLC, mean (SD) | 98.1 (14.2) | 99.3 (14.0) | 101.2 (16.0) | 0.0494 | 0.20 |
↵* Subjects with isolated pleural plaques.
↵† Subjects with pleural plaques and other abnormalities (except interstitial abnormalities and diffuse pleural thickening).
↵‡ Subjects with no CT scan abnormalities.
↵§ 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.