Endemic malignant mesothelioma: exposure to erionite is more important than genetic factors

Our plain-English summary of Endemic malignant mesothelioma: exposure to erionite is more important than genetic factors, by M. Metintas, G. Hillerdal, S. Metintas, et al (Archives of Environmental & Occupational Health, 2010).

The study

• Authors: M. Metintas, G. Hillerdal, S. Metintas, P. Dumortier
• Journal: Archives of Environmental & Occupational Health
• Published: 2010;65(2):86-93
• Cited by: 32 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The village of Karain, Turkey, has the world's highest prevalence rate of malignant mesothelioma (MM). Environmental exposure to erionite is thought to cause the disease. However, it has also been suggested that the disease is mainly genetic. Residents in Karain village were traced from 1990 to 2006. Mineral samples were obtained from stones used in construction of their houses and any fibers present were identified. All women who had moved to the village as brides were traced and their cause of death determined. MM was the cause of death in 52 of 322 villagers, representing 50.5% of all deaths. Only 2 of 8 types of stones used in construction contained erionite, and these stones had been used almost exclusively in the mid-sections of the village, where MM was common. In houses not containing erionite, no cases of MM were observed. Sixty-four women came as brides to Karain from villages where erionite or asbestos is not found. Of the 16 women who have died, 11 (69%) died from MM. The extreme risk of MM in Karain is due to indoor exposure to erionite. The effect of genetic factors on mesothelioma development cannot be evaluated in this study, but is likely to be minor.

In plain English

This field study examined the Turkish village of Karain. The authors traced 322 people who lived there at any time from 1990 to 2006. They used village records, death certificates and hospital records. Where records were missing, they relied on information from relatives and the village headman (a "verbal autopsy"). They also tested the stones and soil used to build the houses for mineral fibers. Of 103 deaths, 52 (22 men, 30 women), or 50.5%, were due to malignant mesothelioma (MM). Of 8 stone types, erionite was found only in Akkusak stone and water stone. These were used mainly in the village's mid-section, where MM occurred in families in nearly all houses. Since 1930, 64 women had moved to Karain as brides from villages where erionite and asbestos have not been found. Of these, 16 had died, 11 (69%) of MM. In a multivariate analysis, only years lived in the village was statistically significant. The authors concluded that the extreme risk was due to indoor erionite exposure in certain houses. They said their data could not settle a genetic role, but that any such role was probably fairly minor.

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: Field study: a village cohort traced through records, death certificates and verbal autopsies, combined with mineral fiber analysis of building stones and soil
• Who was studied: 322 people (154 male, 168 female) who lived in Karain village, Cappadocia, Turkey, at any time from 1990 to 2006, including those who moved away. Separately, the authors studied 64 women who moved to Karain as brides between 1930 and 2006.
• Exposure: Environmental exposure to erionite inside homes, found in two of the stone types used to build houses (Akkusak stone and water stone), and the number of years lived in the village
• Main results:
  • Of 103 deaths in the 1990 to 2006 cohort, 52 were due to MM (22 men and 30 women), about half (50.5%) of all deaths
  • In 32 of the MM cases (62%), the verbal autopsy diagnosis was confirmed by hospital diagnoses
  • Men: average annual MM incidence of 639 per 100,000 (95% CI 597.5–681.1); observed/expected ratio 687.5 (95% CI 447.6–1032.5). The rate for men was significantly lower than for women.
  • Women: average annual MM incidence of 1,267 per 100,000 (95% CI 1231.08–1302.7); observed/expected ratio 1,666.7 (95% CI 1134.1–2319.7)
  • No MM victim in the cohort had lived less than 20 years in the village
  • In the multivariate analysis, only years spent in the village was significant: RR 1.628 (95% CI 1.070–2.474, p = .023). Gender (RR 1.441, 95% CI 0.822–2.528) and being born in the village (RR 0.700, 95% CI 0.332–1.476) were not significant.
  • Erionite-containing stones were used almost exclusively in homes in the mid-sections of the old village, where MM occurred in families in nearly all houses
  • No MM was detected among people who had lived in houses built mostly from Keyrek and Urgup stones (west side), houses built from Akkoy and Urgup stones (east entrance), or houses carved from cave rock (north side)
  • Of 64 women who moved to Karain for marriage from 1930 to 2006, from villages where erionite or asbestos has not been found, 16 had died, and 11 of those deaths (69%) were due to MM
  • Among the brides, MM developed in 9 (38%) of the 24 who had lived in the village 30 years or more, and in 2 (5%) of the 40 with less than 30 years' stay
  • MM developed in 11 (11.8%) of 93 persons who left Karain between 1990 and 2006
  • No mesothelioma was observed among six men who moved to Karain and married Karain women
• The authors' conclusion: The authors concluded that the extreme MM risk in Karain is due to indoor exposure to erionite in certain houses. They said people born in the village and those who moved there (mainly brides) suffer the same risk. They added that any role of genetic susceptibility is probably fairly minor compared to erionite exposure.
• Limitations the authors state:
  • The authors stated that the data from this and other studies are not sufficient to judge whether genetic susceptibility can play a facilitating role
  • The authors said further studies are needed to confirm whether women might be more prone to develop MM than men

Topics

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

Medical terms in this study, explained in our Lexicon: Endemic, Malignant Mesothelioma, erionite, Karain, Environmental Exposure, Mesothelioma.

Related studies

• Lung diseases due to environmental exposures to erionite and asbestos in Turkey — S. Emri, A. Demir, et al. (2002)
• Erionite bodies and fibres in bronchoalveolar lavage fluid (BALF) of residents from Tuzköy, Cappadocia, Turkey — P. Dumortier, L. Coplü, et al. (2001)
• Erionite exposure in North Dakota and Turkish villages with mesothelioma — M. Carbone, Y.I. Baris, et al. (2011)
• Erionite series minerals: mineralogical and carcinogenic properties — A.U. Dogan, M. Dogan, et al. (2008)
• The role of environmental and occupational exposures in Turkish immigrants with fibre-related disease — P. Dumortier, A. Göcmen, et al. (2001)
• Erionite in road gravel associated with interstitial and pleural changes--an occupational hazard in western United States — P.H. Ryan, M. Dihle, et al. (2011)

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