Global magnitude of reported and unreported mesothelioma

Our plain-English summary of Global magnitude of reported and unreported mesothelioma, by E.K. Park, K. Takahashi, T. Hoshuyama, et al (Environmental Health Perspectives, 2011).

The study

• Authors: E.K. Park, K. Takahashi, T. Hoshuyama, T.J. Cheng, V. Delgermaa, G.V. Le, T. Sorahan
• Journal: Environmental Health Perspectives
• Published: 2011;119(4):514-8
• Cited by: 158 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Little is known about the global magnitude of mesothelioma. In particular, many developing countries, including some with extensive historical use of asbestos, do not report mesothelioma.

Objectives: We estimated the global magnitude of mesothelioma accounting for reported and unreported cases.

Methods: For all countries with available data on mesothelioma frequency and asbestos use (n=56), we calculated the 15-year cumulative number of mesotheliomas during 1994-2008 from data available for fewer years and assessed its relationship with levels of cumulative asbestos use during 1920-1970. We used this relationship to predict the number of unreported mesotheliomas in countries for which no information on mesothelioma is available but which have recorded asbestos use (n=33).

Results: Within the group of 56 countries with data on mesothelioma occurrence and asbestos use, the 15-year cumulative number of mesothelioma was approximately 174,300. There was a statistically significant positive linear relation between the log-transformed national cumulative mesothelioma numbers and the log-transformed cumulative asbestos use (adjusted R(2)=0.83, p<0.0001). Extrapolated to the group of 33 countries without reported mesothelioma, a total of approximately 38,900 (95% confidence interval, 36,700-41,100) mesothelioma cases were estimated to have occurred in the 15-year period (1994-2008).

Conclusions: We estimate conservatively that, globally, one mesothelioma case has been overlooked for every four to five reported cases. Because our estimation is based on asbestos use until 1970, the many countries that increased asbestos use since then should anticipate a higher disease burden in the immediate decades ahead.

In plain English

This study estimated worldwide mesothelioma deaths from 1994 to 2008, including cases never reported. The authors used U.S. Geological Survey asbestos-use figures and death records, mainly from the WHO Mortality Database. For 56 countries with both kinds of data, reported deaths totalled 92,133, often for fewer than 15 years. These were scaled up to a 15-year figure of about 174,300. Their cumulative asbestos use during 1920–1970 was strongly associated with their 15-year mesothelioma count (adjusted R2 0.83, p less than 0.0001). The authors applied this relationship to 33 countries with asbestos-use data but insufficient mesothelioma data (Peru and El Salvador had just 2 years' data). They estimated about 38,900 unreported cases there (95% CI 36,700–41,100), led by Russia (21,300). The authors concluded that, conservatively, one case has been overlooked for every four to five reported. Cumulative world asbestos use was 65 million metric tons up to 1970 and 124 million during 1971–2007; the authors said heavily using countries should anticipate a very high burden ahead. They noted the analysis was ecological, lacked fiber-type information, and extrapolated mostly to developing countries.

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: Ecological study comparing countries: national asbestos-use data were related by regression to national mesothelioma death counts, and the relationship was then used to predict unreported cases
• Who was studied: 89 countries or entities: 56 with data on both mesothelioma deaths (1994–2008) and asbestos use, and 33 with asbestos-use data that were treated as lacking mesothelioma data. Two of the 33, Peru and El Salvador, had 2 years of WHO data, which the authors treated as insufficient. Deaths covered all types of mesothelioma (ICD-10 C45); for four countries, malignant neoplasm of the pleura (ICD-9 163) was used instead.
• Exposure: National cumulative asbestos use (production plus import minus export) during 1920–1970, in metric tons, from U.S. Geological Survey data. Fiber types were not known. Cumulative use was 51.2 million metric tons in the 56 countries and 14.2 million in the 33 countries.
• Main results:
  • The 56 countries with mesothelioma data reported 92,133 deaths during 1994–2008.
  • The extrapolated 15-year cumulative total for these 56 countries was about 174,300 cases.
  • The countries with the highest extrapolated 15-year counts were the United States (36,561 cases), the United Kingdom (28,369), Italy (18,530), Germany (15,948) and France (12,390).
  • In the 56 countries, cumulative asbestos use during 1920–1970 was a significant predictor of 15-year cumulative mesothelioma mortality (adjusted R2 0.83, p less than 0.0001).
  • In the 33 countries treated as lacking mesothelioma data, an estimated 38,900 cases (95% CI 36,700–41,100) possibly occurred but were unreported during 1994–2008.
  • The highest predicted unreported counts were in Russia (21,300 cases), Kazakhstan (6,500), China (5,100), India (2,200) and Thailand (500).
  • Combining reported and unreported cases, the authors estimated the global 15-year burden at 213,200.
  • Cumulative world asbestos use was 65 million metric tons up until 1970 and 124 million metric tons in the period since then (1971–2007 in Table 1), which the authors described as a near doubling.
• The authors' conclusion: The authors concluded that, globally, one mesothelioma case has been overlooked for every four to five reported cases, and that their figures are conservative estimates. They said countries that increased asbestos use since 1970 should anticipate a very high burden of mesothelioma in the immediate decades ahead.
• Limitations the authors state:
  • The findings rest on an ecological relation, so the authors did not know how far national asbestos consumption reflected people's actual exposure.
  • The relationship was extrapolated from a mixed group of developed and developing countries to a group of mostly developing countries, which may introduce bias.
  • There was no information on the fiber types consumed.
  • Estimates could be too high because developed countries may have more cases due to older populations.
  • Estimates could be too low: there were no data on trade in asbestos-containing products, many countries had no asbestos-use data, and underdiagnosis occurs even in developed countries.

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, confidence interval.

Related studies

• Global mesothelioma deaths reported to the World Health Organization between 1994 and 2008 — V. Delgermaa, K. Takahashi, et al. (2011)
• Recent mortality from pleural mesothelioma, historical patterns of asbestos use, and adoption of bans: a global assessment — K. Nishikawa, K. Takahashi, et al. (2008)
• Airborne asbestos in buildings — R.J. Lee, D.R. Van Orden (2008)
• Airborne asbestos levels in school buildings in Italy — A. Campopiano, S. Casciardi, et al. (2004)
• Asbestos abatement of pipe and floor tile/mastic and comparison of critical plastic barrier controls — J.H. Lange (2004)
• Where there is asbestos, there is mesothelioma: filling in the data blanks — R.C. Haynes (2011)

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