Malignant mesothelioma in Metsovo, Greece, from domestic use of asbestos: 30 years later

Our plain-English summary of Malignant mesothelioma in Metsovo, Greece, from domestic use of asbestos: 30 years later, by A. Gogali, C. Manda-Stachouli, E.E. Ntzani, et al (The European Respiratory Journal, 2012).

The study

• Authors: A. Gogali, C. Manda-Stachouli, E.E. Ntzani, M. Matthaiou, A.K. Konstantinidis, I. Zampira, C. Koubaniou, Y. Dalavanga, D. Stefanou, S.H. Constantopoulos, G. Daskalopoulos
• Journal: The European Respiratory Journal
• Published: 2012;39(1):217-9
• Type of article: Letter
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Summary of the article

This research letter updated earlier reports on malignant mesothelioma (MM) in Metsovo, a group of villages in Ioannina prefecture, north-west Greece. Earlier work linked MM there to a tremolite asbestos-containing whitewash called 'luto', which was gradually abandoned after 1940–1950 and no longer used by 1990. The authors asked whether, 30 years after the first recorded case, the epidemic was ending. The populations of Metsovo municipality (4,417 inhabitants in 2001) and Ioannina prefecture were followed from January 1980 to December 2009, giving 127,753 and 4,733,915 person-years respectively. Cases were identified through the registries of two tertiary hospitals in Ioannina and the Metsovo death certificate registry. All were histologically confirmed, and none had an asbestos-related occupation. Crude incidence rates were calculated because age data were unavailable. There were 26 MM cases in Metsovo, a rate of 2.04 per 10,000 person-years. Of these, 14 occurred in 1980–1994 and 12 in 1995–2009. The rates for these two 15-year periods were 2.2 and 1.8 per 10,000 person-years (p=0.65). By decade, rates were 2.6, 2.4 and 1.1 per 10,000 person-years (p=0.1 for the last decade versus the previous one). Compared with the rest of Ioannina (1.48 per 1,000,000 person-years), risk in Metsovo was 137-fold higher, falling from 236-fold to 86-fold between the two 15-year periods. The authors concluded that incidence had dropped by half and relative risk by two-thirds, but that no prediction of the epidemic's end was safe.

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In plain English

This research letter updated the authors' earlier reports on malignant mesothelioma in Metsovo, north-west Greece. Households there had used 'luto', a whitewash containing tremolite asbestos. The team followed the Metsovo municipality population (4,417 inhabitants in 2001) and the rest of Ioannina prefecture from 1980 to 2009. None of the patients had an asbestos-related job. Metsovo had 26 cases, a crude rate of 2.04 per 10,000 person-years. Twelve occurred in 1995–2009 (10 pleural, two peritoneal), all in people who had used luto in 1950–1970. The 1995–2009 rate (1.8 per 10,000 person-years) was not statistically different from the 1980–1994 rate (2.2). The last decade's rate (1.1 per 10,000 person-years) was less than half the previous decade's (2.4; p=0.1), which the authors called a trend. Metsovo residents had an estimated 137-fold higher risk than the rest of Ioannina (95% CI 58.2–375.6). This fell from 236-fold in the first 15 years to 86-fold in the second. The authors concluded that abandoning luto had cut incidence to one-half and relative risk to one-third, and that the epidemic may still end by 2020–2030, though no prediction is safe. Rates were not age-adjusted.

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: Research letter updating a population-based incidence study (crude incidence rates over 30 years of follow-up, compared between time periods and with the surrounding prefecture)
• Who was studied: Inhabitants of the Metsovo municipality (villages of Metsovo, Milia, Anilio and Votonossi; 4,417 inhabitants in the 2001 census), Ioannina prefecture, north-west Greece. They were compared with the rest of the Ioannina prefecture population, followed January 1980 to December 2009 (127,753 person-years for Metsovo, 4,733,915 for Ioannina). Cases were histologically confirmed and were identified from two Ioannina hospitals' registries or the Metsovo death certificate registry.
• Exposure: Non-occupational, domestic exposure to tremolite asbestos from 'luto', a whitewash used in Metsovo homes. The patients diagnosed in 1995–2009 had used it during 1950–1970.
• Main results:
  • None of the mesothelioma patients had a history of an asbestos-related occupation
  • Metsovo municipality had 26 malignant mesothelioma cases over 1980–2009, a cumulative incidence rate of 2.04 per 10,000 person-years
  • In 1995–2009, 12 more cases from Metsovo were diagnosed (10 pleural, two peritoneal), after 14 in the first 15 years
  • Of these 12 patients, three were male and nine female, aged 50–86. All were confirmed to have used luto during 1950–1970.
  • Metsovo incidence did not differ significantly between 1980–1994 (2.2 per 10,000 person-years) and 1995–2009 (1.8 per 10,000 person-years), p=0.65
  • By decade, Metsovo rates were 2.6 and 2.4 per 10,000 person-years in the first two decades. The last decade's rate was 1.1 per 10,000 person-years, less than half the previous decade's (p=0.1, described as a trend of decrease).
  • Metsovo incidence (2.04 per 10,000 person-years) was significantly higher than in the Ioannina population outside Metsovo (1.48 per 1,000,000 person-years), p less than 0.001. This indicated a 137-fold risk increase (95% CI 58.2–375.6).
  • The increased risk in Metsovo compared with the rest of Ioannina fell from 236-fold in 1980–1994 to 86-fold in 1995–2009
  • The earlier drop in cases between 1980–1984 and 1985–1994 did not continue. Cases rose in 1995–1999 and dropped again, with only one case in the last 7 years (in 2005).
• The authors' conclusion: The authors concluded that abandoning the tremolite-containing whitewash had resulted in mesothelioma incidence falling to one-half and relative risk to one-third. They concluded that their earlier view that the epidemic could disappear by 2020–2030 may still be valid. Because a rare case could take up to 70 years to develop, they said no prediction is safe.
• Limitations the authors state:
  • Rates were crude, not age-adjusted, because the age structure of the population was not known
  • The fluctuations could be due to chance. A far longer follow-up and a far larger population would be needed to reach statistically significant differences.
  • The authors suggested that intense demolition of luto-containing houses in 1960–1970 may explain the rise in cases in 1995–1999. They described this explanation as very difficult to prove.

Topics

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

Medical terms in this study, explained in our Lexicon: Malignant Mesothelioma, Tremolite, Whitewash, Luto, Death Certificate, Incidence, Relative Risk.

Related studies

• Evidence Suggesting the End of Universal Domestic Asbestos Exposure in Metsovo, NW Greece — A. Gogali, E.E. Ntzani, et al. (2017)
• Malignant pleural mesothelioma from nonoccupational asbestos exposure in Metsovo (north-west Greece): slow end of an epidemic? — K. Sakellariou, V. Malamou-Mitsi, et al. (1996)
• Metsovo lung outside Metsovo. Endemic pleural calcifications in the ophiolite belts of Greece — S.H. Constantopoulos, P. Theodoracopoulos, et al. (1991)
• Metsovo lung: pleural calcification and restrictive lung function in northwestern Greece. Environmental exposure to mineral fiber as etiology — S.H. Constantopoulos, J.A. Goudevenos, et al. (1985)
• Metsovo-tremolite asbestos fibres: in vitro effects on mutation, chromosome aberration, cell transformation and intercellular communication — K. Athanasiou, S.H. Constantopoulos, et al. (1992)
• Proteome analysis of bronchoalveolar lavage in individuals from Metsovo, nonoccupationally exposed to asbestos — D.T. Archimandriti, Y.A. Dalavanga, et al. (2009)

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