Cross-sectional (internal comparison group) X-ray studies of pleural plaques and lung function included in meta-analysis
| Reference, population | X-ray details | Smoking consideration | Study groups |
|---|---|---|---|
| Bresnitz et al25 Philadelphia Construction—elevator Screening programme through union, 1988. n=91 (n eligible not available) | Two readers, blinded | Authors noted no association between pleural abnormalities and smoking | Excluded profusion scores ≥1/0 Pleural thickening, n=20 (15 bilateral, 5 unilateral) No pleural abnormalities, n=71 |
| Di Lorenzo et al26 Italy Asbestos cement factory Recruited through union n=30 (of 35, 86% participation) Eligibility criteria not described | Two readers, blinded | Authors noted smoking distribution similar across groups | Excluded profusion scores ≥1/1 Pleural plaques, n=10, No bronchial, parenchymal or pleural disease, n=9 |
| Dujić et al27 Croatia Asbestos cement factory Current and retired workers n=344, 284 current and 58 retired workers (92% and 52% participation, respectively) | Two readers, blinded | Difference in smoking prevalence (62% vs 38%) not addressed | Excluded profusion scores ≥1/1 Isolated pleural plaques, n=55, Workers with no radiographic change, n=255 |
| García-Closas and Christiani28 Massachusetts Construction—carpenters Invited by union 1987–1988 n=631, 618 current and 13 retired workers (16% and 3% participation, respectively) | Two readers, blinded | Less than 10% difference in smoking prevalence between groups | Excluded profusion scores ≥0/1 Circumscribed plaque without obliteration of costophrenic angle, n=64 No X-ray abnormalities, n=457 |
| Hilt et al29 Norway Asbestos-exposed workers County-wide screening, n=21 483; 1431 referred for re-examination if X-ray abnormalities n=1372 (96%) participated | Two readers, blinding not reported | Percentage predicted included smoking variable | Profusion scores details not discussed Pleural plaques only, n=363 No abnormalities, previous exposure reported, n=98 |
| Järvholm and Sandén30 Sweden Shipping industry General screening 1977–1979 n=3904 participated; participation rate not reported | One reader from group of three, blinding not reported | Limited to nonsmokers | Circumscribed thickening, n=87 No X-ray abnormalities, n=115 |
| Järvholm and Larsson23 Sweden Asbestos-exposed workers General screening 1976 n=4268, participation rate not reported | One reader from group, blinding not reported | Analyses stratified by smoking status | Profusion scores details not discussed Calcifications typically localised on the diaphragm or chest wall, n=130 No pleural plaques, n=1103 |
| Miller et al31 USA, Canada Insulation workers 1981–1983 screening of cohort established in 1967 n=2611, participation rate approximately 40% | One reader, blinded | Smoking data by group not reported and not included in analysis. | Included profusion scores 0/− or 0/0 Circumscribed pleural plaques, n=121 No pleural thickening, n=203 |
| Miller et al32 USA (four states) Screening programme through unions, 1997–2004 (medicolegal evaluation) n=4003 | One reader, blinded | Smoking data by group not reported and not included in analysis. | |
| Ohlson et al33 Sweden Asbestos cement plant Screening in 1976 (after plant closed), participation rate 96% n=75 (used follow-up data because quantitative results reported) | One reader, blinding not reported | Less than 10 pack-year difference between groups | Profusion scores details not discussed Pleural plaques (not defined), n=42 No pleural plaques, n=51 |
| Oliver et al34 Pennsylvania Railroad workers Screening study n=377 | Two readers, blinding not reported | Adjusts for smoking in the analysis | Excluded profusion scores ≥0/1 Plaque-like thickening, n=81 No plaques, n=278 |
| Schwartz et al35 Iowa Sheet metal workers union, 1223 of 2646 (46%) participated n=1211 with X-rays | One reader (plus 10% validation study), blinded | Adjusts for pack-years in analysis | Excluded profusion scores ≥1/0 (table 9) Circumscribed plaque without obliteration of costophrenic angle, n=260 (before profusion score exclusion) No pleural changes, n=877 (before profusion score exclusion) |
| Singh et al21 Australia Asbestos-exposed (various sources) Seen in outpatient clinic because of asbestos exposure, 1994–1995 n=26 | One reader, blinding not reported | Difference in smoking prevalence (8% and 0%, based on single individuals) not addressed | Profusion scores details not discussed Costal and/or diaphragmatic plaques with no involvement of costophrenic angle, n=12 No pleural disease, n=7 |
| Weill et al36 Montana (Libby) Community screening, former workers, family members and other area residents n=4397 | Consensus of two of three readers, blinding not reported | Stratified by smoking status (ever/never) within men and women | Excluded profusion scores ≥1/0 Pleural abnormality excluding DPT, costophrenic angle obliteration or interstitial disease, n=482 No abnormality, n=4065 |
| Zavalić and Bogadi-Sare37 Croatia Shipyard workers | Consensus of two of three readers, blinding not reported | Authors noted smoking distribution similar across groups | Excluded profusion scores >0/0 from analysis of table 5 Pleural plaques only, n=68 No changes, n=101 |