Ecological association between asbestos-related diseases and historical asbestos consumption: an international analysis

Our plain-English summary of Ecological association between asbestos-related diseases and historical asbestos consumption: an international analysis, by R.T. Lin, K. Takahashi, A. Karjalainen, et al (Lancet, 2007).

The study

• Authors: R.T. Lin, K. Takahashi, A. Karjalainen, T. Hoshuyama, D. Wilson, T. Kameda, C.C. Chan, C.P. Wen, S. Furuya, T. Higashi, L.C. Chien, M. Ohtaki
• Journal: Lancet
• Published: 2007;369(9564):844-849
• Type of article: Historical article
• Cited by: 184 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: The potential for a global epidemic of asbestos-related diseases is a growing concern. Our aim was to assess the ecological association between national death rates from diseases associated with asbestos and historical consumption of asbestos.

Methods: We calculated, for all countries with data, yearly age-adjusted mortality rates by sex (deaths per million population per year) for each disease associated with asbestos (pleural, peritoneal, and all mesothelioma, and asbestosis) in 2000-04 and mean per head asbestos consumption (kg per person per year) in 1960-69. We regressed death rates for the specified diseases against historical asbestos consumption, weighted by the size of sex-specific national populations.

Findings: Historical asbestos consumption was a significant predictor of death for all mesothelioma in both sexes (adjusted R2=0.74, p<0.0001, 2.4-fold [95% CI 2.0-2.9] mortality increase was predicted per unit consumption increase for men; 0.58, p<0.0001, and 1.6-fold [1.4-1.9] mortality increase was predicted for women); for pleural mesothelioma in men (0.29, p=0.0015, 1.8-fold [1.3-2.5]); for peritoneal mesothelioma in both sexes (0.54, p<0.0001, 2.2-fold [1.6-2.9] for men, 0.35, p=0.0008, and 1.4-fold for women [1.2-1.6]); and for asbestosis in men (0.79, p<0.0001, 2.7-fold [2.2-3.4]). Linear regression lines consistently had intercepts near zero.

Interpretation: Within the constraints of an ecological study, clear and plausible associations were shown between deaths from the studied diseases and historical asbestos consumption, especially for all mesothelioma in both sexes and asbestosis in men. Our data strongly support the recommendation that all countries should move towards eliminating use of asbestos.

In plain English

This ecological study compared countries, not individuals. The authors compared age-adjusted death rates in 2000–04 from pleural, peritoneal and all mesothelioma and from asbestosis, for men and women separately, with average asbestos consumption per person in 1960–69. Depending on the disease and sex, each comparison used 19 to 32 of 33 countries. This allowed about 30–40 years between exposure and death. Higher past consumption went with higher death rates. Per extra 1 kg of asbestos per person per year, predicted mesothelioma deaths rose 2.4-fold (95% CI 2.0 to 2.9) in men and 1.6-fold (1.4 to 1.9) in women, and asbestosis deaths rose 2.7-fold (2.2 to 3.4) in men. The links for pleural mesothelioma and asbestosis in women were not statistically significant. Lung cancer was left out because of its link with smoking and a lack of comparable data to adjust for it. The authors noted limits: consumption figures did not reflect fibre type, occupation or sex, and China, India and Russia were missing. They said findings should be read within an ecological study's limits. They concluded their results support all countries moving towards eliminating asbestos use.

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 (country-level) study using population-weighted linear regression of national death rates against historical national asbestos consumption
• Who was studied: 33 countries with both asbestos consumption data (1960–69) and WHO mortality data (2000–04). Together they accounted for 63% of world asbestos consumption in 1960–69 and 22% of the world population in 2000–04. The number of countries in each analysis varied by disease and sex, from 19 to 32.
• Exposure: National asbestos consumption per head (kg per person per year), defined as production plus import minus export divided by population, averaged for 1960–69 from US Geological Survey data. Fibre types were not distinguished.
• Main results:
  • All mesothelioma, men (32 countries): adjusted R2 0.74, p less than 0.0001. Predicted deaths rose 2.4-fold (95% CI 2.0 to 2.9) per 1 kg per head increase in consumption.
  • All mesothelioma, women (31 countries): adjusted R2 0.58, p less than 0.0001. Predicted deaths rose 1.6-fold (1.4 to 1.9) per 1 kg per head.
  • Pleural mesothelioma, men (29 countries): R2 0.29, p=0.0015, 1.8-fold (1.3 to 2.5) increase per 1 kg. In women the relation was not statistically significant (p=0.107).
  • Peritoneal mesothelioma: 2.2-fold (1.6 to 2.9) increase per 1 kg in men (R2 0.54, p less than 0.0001) and 1.4-fold (1.2 to 1.6) in women (R2 0.35, p=0.0008).
  • Asbestosis, men (27 countries): R2 0.79, p less than 0.0001, 2.7-fold (2.2 to 3.4) increase per 1 kg. In women (19 countries) the association was not significant (p=0.2375 in the table).
  • For all mesothelioma, the predicted male-to-female death rate ratio at the mean consumption of 1.67 kg per head was 3.0.
  • Regression lines had intercepts close to zero for all the diseases studied. The authors note the findings cannot be extrapolated beyond the data range.
• The authors' conclusion: The authors concluded that there were clear and plausible positive relations between historical asbestos consumption and later deaths from asbestos-related diseases. These were most apparent in men but also present in women. The authors said their results lend support to all countries moving towards eliminating asbestos use.
• Limitations the authors state:
  • Only countries with both consumption and mortality data could be included, which excluded populous countries such as China, India and Russia.
  • The authors did not know whether the amounts of asbestos consumed equal the amounts people were exposed to.
  • The consumption measure did not account for fibre types (such as amphiboles or chrysotile), nor for sex, age or occupation.
  • Data from developing countries were probably of poorer quality, leading to a likely negative bias.
  • Lung cancer was excluded because of its link with smoking and a lack of reliable, comparable data for adjustment.
  • Pleural mesothelioma results may have been affected by fewer cases and by some countries lacking data for mesothelioma subcategories.

Topics

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

Medical terms in this study, explained in our Lexicon: Mesothelioma, Pleural Mesothelioma, Peritoneal Mesothelioma.

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• Recent mortality from pleural mesothelioma, historical patterns of asbestos use, and adoption of bans: a global assessment — K. Nishikawa, K. Takahashi, et al. (2008)
• International scientific cooperation on asbestos-related disease prevention in Latin America — D. Marsili, P. Comba, et al. (2014)
• Asbestos consumption, asbestos exposure and asbestos-related occupational diseases in Germany — O. Hagemeyer, H. Otten, et al. (2006)
• Diseases related to asbestos exposure: historical perspective — H.P. Pendergrass, J.D. Snell, et al. (1987)
• Upcoming epidemic of asbestos-related malignant pleural mesothelioma in Taiwan: A prediction of incidence in the next 30 years — R.T. Lin, Y.Y. Chang, et al. (2019)

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