Malignant mesothelioma due to environmental exposure to asbestos: follow-up of a Turkish cohort living in a rural area

Our plain-English summary of Malignant mesothelioma due to environmental exposure to asbestos: follow-up of a Turkish cohort living in a rural area, by S. Metintas, M. Metintas, I. Ucgun, et al (Chest, 2002).

The study

• Authors: S. Metintas, M. Metintas, I. Ucgun, U. Oner
• Journal: Chest
• Published: 2002;122(6):2224-9
• Cited by: 103 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Study Objectives: This study examines the incidence of malignant pleural mesothelioma (MPM) in a rural population of Turkey with environmental exposure to asbestos-contaminated soil mixtures (white soil).

Design: A field-based epidemiologic study.

Setting And Subjects: A cohort of villagers (the "Eskisehir" cohort) from 11 villages around Eskisehir in central Anatolia, who had been environmentally exposed to asbestos due to the use of white soil.

Measurements: The mineral content and asbestos contamination of the white soil used in these villages was determined, as well as airborne fiber concentrations. Cohort members' details of age, sex, ambient exposure data, duration of residence in the villages, and hospital records, including pathologic diagnosis, were recorded.

Results: The Eskisehir cohort consisted of 1,886 villagers. During the observation time, 377 deaths occurred and 24 MPM cases were diagnosed. Average annual mesothelioma incidence rates were 114.8/100,000 for men and 159.8/100,000 for women.

Conclusions: These data indicate that the risk of mesothelioma is 88.3 times greater in men and 799 times greater in women, respectively, in comparison to world background incidence rates.

In plain English

In this field-based epidemiologic study, the authors followed 1,886 villagers aged 30 and over from 11 villages around Eskisehir in central Anatolia, Turkey, where an asbestos-contaminated local soil called white soil was used. Follow-up ran from 1990 to 2000 using village registers, health center files, hospital records and family interviews. White soil from all 11 villages contained asbestos, mostly tremolite or mixtures of tremolite, actinolite and chrysotile. Indoor air averaged 0.089 fibers per milliliter. Twenty-four villagers (12 men, 12 women) developed malignant pleural mesothelioma. Only 0.228 cases were expected among men and 0.083 among women. The ratio of observed to expected cases was 52.63 (95% confidence interval 29.88 to 92.64) for men and 143.9 (81.71 to 253.36) for women. The average annual incidence, age-standardized to the Segi world standard population, was 114.8 per 100,000 for men and 159.8 per 100,000 for women. The authors concluded that the risk was 88.3 times greater in men and 799 times greater in women than world background rates, and similar to occupationally exposed asbestos cohorts. They noted that their air measurements likely underestimated true exposures.

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-based epidemiologic cohort study. Villagers were followed from 1990 to 2000 using village (muhtar) registers, state health center files, hospital records and family interviews. Observed mesothelioma cases were compared with the number expected from Izmir Cancer Registry rates.
• Who was studied: The 'Eskisehir' cohort: 1,886 villagers aged 30 and over (997 men, 889 women) from 11 villages chosen by random sampling among 41 villages around Eskisehir, central Anatolia, Turkey, where white soil was found contaminated with asbestos.
• Exposure: Lifelong environmental exposure, from birth, to asbestos-contaminated white soil. The authors report no occupational asbestos exposure in these areas. Soil from all 11 villages contained asbestos: a high rate of tremolite or tremolite-plus-actinolite-plus-chrysotile mixtures, and a lower rate of anthophyllite-plus-chrysotile mixtures.
• Main results:
  • Indoor air fiber concentrations in the villages ranged from 0.009 to 0.28 fibers per milliliter (mean 0.089). Outdoor concentrations ranged from 0.009 to 0.04 fibers per milliliter (mean 0.012).
  • Of the 1,886 villagers, 24 (12 men and 12 women) had malignant pleural mesothelioma between 1990 and 2000.
  • Mesothelioma accounted for 5.6% of deaths in the cohort (21 of 377 deaths).
  • Patients' ages at diagnosis ranged from 36 to 76 years (mean 56.5). Because exposure began at birth, the authors treated age at diagnosis as the latency period. The difference in latency between male and female patients was not statistically significant.
  • Only 0.228 mesothelioma cases were expected among the men and 0.083 among the women in the cohort, against 12 observed in each group.
  • The mesothelioma standardized incidence ratio for men was 52.63 (95% confidence interval 29.88 to 92.64). For women it was 143.9 (95% confidence interval 81.71 to 253.36).
  • The authors calculated directly age-standardized average annual mesothelioma incidence rates, adjusted to the Segi standard population. These were 114.8 per 100,000 for men and 159.8 per 100,000 for women. Compared with world background rates, they were 88.3 times higher for men and 799.0 times higher for women. Compared with Turkish rates, they were 191.3 times higher for men and 532.7 times higher for women.
• The authors' conclusion: The authors concluded that, for villagers exposed to asbestos through use of white soil, mesothelioma risk was 88.3 times greater in men and 799 times greater in women than world background incidence rates, and similar to occupationally exposed asbestos cohorts.
• Limitations the authors state:
  • The authors stated that their ambient air measurements most likely underestimate true exposures over a 24-hour period, because levels vary with conditions and with activities such as whitewashing and sweeping.
  • The authors stated that the membrane filter counting method cannot count very thin fibers, described as invisible fibers of about 0.25 micrometers in diameter (the comparison symbol is lost in the text), which may be responsible for mesotheliomas. Measured fiber levels may therefore be lower than actual levels.

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, Environmental Exposure, Pleural Mesothelioma, Mesothelioma, Incidence.

Related studies

• Environmental asbestos exposure in rural Turkey and risk of lung cancer — S. Metintas, M. Metintas, et al. (2012)
• Nonmalignant pleural lesions due to environmental exposure to asbestos: a field-based, cross-sectional study — M. Metintas, S. Metintas, et al. (2005)
• Concentrations of asbestos fibers and metals in drinking water caused by natural crocidolite asbestos in the soil from a rural area — B. Wei, B. Ye, et al. (2013)
• A review of the cohorts with environmental and occupational mineral fiber exposure — S. Metintas, G. Ak, et al. (2019)
• Topsoil and urban dust pollution and toxicity in Taranto (southern Italy) industrial area and in a residential district — M. Trifuoggi, G. Pagano, et al. (2018)
• Environmental asbestos exposure and malignant pleural mesothelioma — M. Metintas, N. Ozdemir, et al. (1999)

Browse more research in Chest, or return to medical research.