Radiological study of pleural changes in relation to mesothelioma in Turkey

Our plain-English summary of Radiological study of pleural changes in relation to mesothelioma in Turkey, by G. Hillerdal, Y.I. Baris (Thorax, 1983).

The study

• Authors: G. Hillerdal, Y.I. Baris
• Journal: Thorax
• Published: 1983;38(6):443-8
• Cited by: 20 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 000612).

Abstract

In some villages in central Turkey pleural changes occur as a result of environmental exposure to mineral fibres. In most cases the fibre is asbestos but in some cases the non-asbestos fibre erionite, a zeolite, is responsible. The incidence of malignant mesothelioma is much higher in "erionite villages" than in "asbestos villages" despite similar frequencies of pleural changes. In this study chest radiographs from 466 people from asbestos villages, 549 from erionite villages, and 382 controls were compared. The frequency of pleural calcification was about the same in the two groups of villages studied, but the minor fissures were visible to a greater degree in erionite cases. In people from erionite villages "atypical" pleural calcification, due to calcification of the visceral rather than the parietal pleura, was more common. These differences may indicate that the fibres have different lengths and diameters.

In plain English

This study re-examined chest X-rays taken during earlier field surveys in villages in central Anatolia, Turkey. It compared 466 adults from four villages with environmental asbestos exposure, 549 from two villages exposed to erionite (a non-asbestos fibrous mineral, a zeolite), and 382 from control villages. The authors noted that mesothelioma is far more common in the erionite villages. Pleural calcification was seen in 22.3% of asbestos-village adults, 14.2% of erionite-village adults and under 1% of controls. A visible minor fissure (pleura between lung lobes) was more common in erionite villages (34.2% versus 21.2%, p less than 0.001). An 'atypical' calcification on the lung surface was found in 8 of 10 erionite-village cases of diffuse pleural thickening, against 3 of 15 in asbestos villages. Discrete calcified plaques, excluding the atypical cases, were equally common in both. The authors concluded that the differences can probably be explained by differences in fibre length and diameter, a hypothesis needing further research. Only one X-ray view, of varied quality, was available. All films showing no pleural change had been withdrawn from one asbestos village, Mihaliccik.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Radiological comparison (re-reading of existing chest X-rays from earlier field studies) of asbestos-exposed, erionite-exposed and control villages
• Who was studied: Adults from a randomised sample of villages in central Anatolia, Turkey: 549 radiographs from erionite villages (Sarihidir and Tuzkoy), 466 from asbestos villages (Gurpinar, Maden, Mihaliccik, Sarihaya), 382 from control villages without pleural disease. Dates of the original surveys not given.
• Exposure: Environmental (non-occupational) exposure to mineral fibres. In asbestos villages the soil and rocks yield chrysotile and amphiboles, mostly the amphibole tremolite, used locally for baby powder and whitewashing houses. In erionite villages the exposure is to erionite, a fibrous zeolite in volcanic tuff, starting in infancy. Control villages had no such exposure.
• Main results:
  • Pleural calcification was found in 22.3% (104 of 466) of adults from asbestos villages, 14.2% (78 of 549) from erionite villages, and less than 1% (3 of 382) from control villages.
  • A visible minor fissure was seen in 188 (34.2%) erionite-village radiographs versus 99 (21.2%) asbestos-village radiographs, a significant difference (p less than 0.001). Among those without pleural calcification, thickening of the minor fissure was seen in 26% of erionite-exposed and 15.7% of asbestos-exposed villagers.
  • Bilateral loss of the costophrenic angle was not seen in controls and was most common in erionite villagers. Obscured costophrenic angle overall: 36 (7.7%) in asbestos villages versus 53 (9.7%) in erionite villages, difference not significant.
  • Among people with calcified pleura, visible minor fissures (45 of 78, 57.7%, erionite versus 44 of 104, 42%, asbestos) and rounded costophrenic angles (25, 32%, versus 25, 24%) were more frequent in erionite villages, but the difference was not significant.
  • 'Atypical' calcification, affecting the lung surface rather than the parietal pleura, was found in 8 of the 10 cases of diffuse pleural thickening from erionite villages (three bilateral), compared with three of the 15 cases from asbestos villages (all unilateral).
  • The prevalence of discrete pleural plaques, excluding atypical cases, was the same in erionite and asbestos villages. Plaques were recorded only when calcified, so this refers to discrete calcified plaques.
• The authors' conclusion: The authors concluded that the differences between areas with endemic pleural changes can probably be explained by differences in the length and diameter of the fibres responsible, and that this hypothesis needs to be tested by further epidemiological and mineralogical research. They also noted that atypical changes were associated with mesothelioma in the asbestos villages and even more so in the erionite villages.
• Limitations the authors state:
  • Only posteroanterior films were available and their quality varied, so plaques were recorded only when calcified.
  • All films showing no pleural change had been withdrawn from the Mihaliccik (asbestos village) set, and about a dozen films had been withdrawn from other sets for clinical care.
  • The fibre-dimension explanation is a hypothesis that the authors say still needs testing.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: Mesothelioma, Environmental Exposure, erionite, Zeolite, Malignant Mesothelioma, Chest X-Ray, Pleural Calcification, Parietal Pleura.

Related studies

• Radiological changes in asbestos cement workers — K. Jakobsson, U. Strömberg, et al. (1995)
• The human evidence: parenchymal and pleural changes — G. Hillerdal (1994)
• Lung function, radiological changes and exposure: analysis of ATSDR data from Libby, MT, USA — D. Weill, G. Dhillon, et al. (2011)
• Radiological features of asbestos-related visceral pleural changes — A. Solomon (1991)
• Environmental asbestos-related pleural plaque in southeast of Turkey — G. Ates, T. Yildiz, et al. (2010)
• Biopersistence of refractory ceramic fiber in human lung tissue and a 20-year follow-up of radiographic pleural changes in workers — J.E. Lockey, V.L. Roggli, et al. (2012)

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