Tremolite whitewashing and pleural calcifications

Our plain-English summary of Tremolite whitewashing and pleural calcifications, by S.H. Constantopoulos, N.A. Saratzis, D. Kontogiannis, et al (Chest, 1987).

The study

• Authors: S.H. Constantopoulos, N.A. Saratzis, D. Kontogiannis, A. Karantanas, J.A. Goudevenos, P. Katsiotis
• Journal: Chest
• Published: 1987;92(4):709-12
• Cited by: 26 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 000955).

Abstract

Radiologic screening of 688 inhabitants of the Metsovo area in Northwest Greece revealed that 323 (46.9 percent) had pleural calcifications. The percentage of positive examinations rose with age. Calcifications were observed in all four villages of the area where a material ("luto" soil) had been extensively used for whitewashing until 1940 to 1950. In four other villages in the immediate vicinity, where "luto" had never been used, pleural calcifications were not observed. Results suggest that Metsovo tremolite may have caused pleural calcifications to all individuals born in Metsovo before 1940. This is the first study indicating that environmental asbestos exposure can cause abnormalities in everyone exposed to it.

In plain English

This study looked at pleural calcifications (calcium deposits on the lining around the lungs) in four neighboring villages of the Metsovo area in Northwest Greece. There, a local soil called "luto", found to consist of tremolite fibers, was used for whitewashing. Chest X-rays of 688 inhabitants showed calcifications in 323 (46.9 percent), rising from 4.5 percent of people aged 25 to 39 to 71.5 percent of those 70 and older. Among people aged 40 to 59, 6 of 27 (22.2 percent) who had used luto for 20 to 29 years had calcifications, compared with 12 of 25 (48 percent) who had used it for 30 to 39 years. Luto had never been used in four nearby villages where the authors' earlier study found no calcifications. CT scans found calcifications in all 18 people born before 1940 whose X-rays showed no calcifications, and in none of 12 people scanned from the luto-free villages. The authors concluded that luto tremolite and the calcifications appear causally related, and that very likely everyone in Metsovo born before 1940 has calcifications. They said further studies were needed.

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: Cross-sectional radiologic (chest X-ray) screening with a questionnaire on luto use, a comparison of two exposure-duration groups, and chest CT in a selected subgroup with CT controls from neighboring villages
• Who was studied: 688 inhabitants of four villages (Metsovo, Milea, Anilio, Votonossi) in Northwest Greece. Of these, 240 answered questions on luto use, and 52 people aged 40 to 59 were compared by years of use. CT was done in 18 people born before 1940 whose X-rays showed no pleural calcifications (nine men and nine women, aged 46 to 91, mean 62.2). The CT controls were 12 people from four luto-free villages (aged 54 to 84, mean 67.9).
• Exposure: Environmental exposure to "luto", a soil from local outcroppings used for whitewashing, found to consist of tremolite fibers. It was used by virtually all households until 1940 and is now used by less than 10 percent of those questioned.
• Main results:
  • 323 of 688 chest X-rays (46.9 percent) showed pleural calcifications.
  • The frequency of calcifications rose with age, from 4.5 percent in the 25 to 39 age group to 71.5 percent in those 70 and older.
  • Among people aged 40 to 59, 6 of 27 (22.2 percent) with 20 to 29 years of luto use (group A) had calcifications, versus 12 of 25 (48 percent) with 30 to 39 years of use (group B). The chi-square value was 3.81, with p less than 0.05.
  • In the four neighboring villages where the earlier study had found no calcifications, luto had never been used.
  • Chest CT showed calcifications in all 18 people born before 1940 whose X-rays were negative for calcifications. In 16 of the 18 the calcifications were very minute. Two of the 18 had more extensive calcifications, and both had evidence of old pleurisy.
  • No calcifications were seen on CT in any of the 12 controls from the luto-free villages.
• The authors' conclusion: The authors concluded that their results suggest a causal relationship between the tremolite used for whitewashing (luto) and the pleural calcifications in the Metsovo area. They also concluded that very likely the whole population of Metsovo born before 1940, and thus exposed to luto, has calcifications.
• Limitations the authors state:
  • Plain chest X-rays can underestimate pleural calcifications, which is why CT was added.
  • The study did not determine the true frequency of calcifications in younger people or the age at which they first appear.
  • The authors could not tell whether the findings reflect a particularly potent "Metsovo tremolite", the first use of a very sensitive method (CT), or increased susceptibility in the Metsovo population. They noted the population belongs to a different ethnic subgroup (Vlachi) from its neighbors, and said further studies were needed.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Pleural plaques and thickening, Tremolite.

Medical terms in this study, explained in our Lexicon: Tremolite, Pleural Calcification, Luto, Asbestos Exposure.

Related studies

• Association of Metsovo lung and pleural mesothelioma with exposure to tremolite-containing whitewash — A.M. Langer, R.P. Nolan, et al. (1987)
• Pleural effects of tremolite in north-west Greece — T. Bazas (1987)
• Metsovo lung outside Metsovo. Endemic pleural calcifications in the ophiolite belts of Greece — S.H. Constantopoulos, P. Theodoracopoulos, et al. (1991)
• An epidemiological study in an Anatolian village environmentally exposed to tremolite asbestos — Y.I. Baris, N. Bilir, et al. (1988)
• Radiological survey of past and present vermiculite miners exposed to tremolite — J.C. McDonald, P. Sebastien, et al. (1986)
• Pleural calcification, pleural mesotheliomas, and bronchial cancers caused by tremolite dust — S. Yazicioglu, R. Ilçayto, et al. (1980)

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