Estimation of future mortality from pleural malignant mesothelioma in Japan based on an age-cohort model

Our plain-English summary of Estimation of future mortality from pleural malignant mesothelioma in Japan based on an age-cohort model, by T. Murayama, K. Takahashi, Y. Natori, et al (American Journal of Industrial Medicine, 2006).

The study

• Authors: T. Murayama, K. Takahashi, Y. Natori, N. Kurumatani
• Journal: American Journal of Industrial Medicine
• Published: 2006;49(1):1-7
• Cited by: 114 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: Japanese consumption of asbestos increased rapidly after the 1950s and lingered at a high level while the world's consumption decreased substantially after the 1980s. Mesothelioma is due primarily to asbestos, and the number of deaths in Japan is expected to increase in the future.

Method: We estimated the future number of pleural mesothelioma deaths among males in Japan using an age-cohort model.

Results: Analyses showed that there would be about 100,000 deaths in Japan due to pleural mesothelioma in the next 40 years. Compared with the statistics in European countries, the ratio of expected death numbers to the population size is remarkably close to linear. The data-point for Japan was slightly lower than that which could be expected from the linear relationship.

Conclusions: The limited availability of data may result in underestimation. Taking into consideration the consumption pattern of asbestos in recent decades, the incorporation of later cohorts will improve the estimation.

Am. J. Ind. Med. 49:1-7, 2006. (c) 2005 Wiley-Liss, Inc.

In plain English

This study used a statistical model to project future deaths from pleural mesothelioma, a cancer of the lining of the chest, among men in Japan. Japan had no national mesothelioma registry, so the authors used government death statistics for 1980 to 1999. Before 1995, death records did not separate pleural mesothelioma from other cancers of the chest lining, so the authors adjusted those older counts to estimate mesothelioma deaths. They applied an age-cohort model, earlier used by Peto and colleagues, to men born between 1895 and 1964. They projected deaths for 2000 to 2039. The model closely matched past deaths. Modelled lifetime risk, calculated with the 1960 life table, was highest for men born in 1950 to 1959: 3.21 per 1,000 (95% confidence interval 1.21 to 8.47 per 1,000). The projection was about 101,400 deaths in 2000 to 2039, with deaths peaking in 2030 to 2034. Compared with published European projections, Japan's expected deaths relative to its population were slightly lower than the European pattern. Men born after 1964 could not be included, so the authors concluded the projection very likely underestimates future deaths.

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: Modelling study projecting future deaths, using an age-cohort model (from Peto et al. 1995) fitted by log-linear Poisson regression to national death statistics
• Who was studied: Japanese males. Pleural mesothelioma deaths from Japanese government vital statistics for 1980 to 1999, in birth cohorts from 1895 to 1904 through 1955 to 1964 and age groups from 25 to 29 through 85 to 89. Deaths were projected for 2000 to 2039.
• Exposure: No individual exposure was studied. Japan's national asbestos consumption is given as background. The model extrapolated from past death counts and did not use asbestos consumption. No fiber types are named.
• Main results:
  • The model closely reproduced the observed deaths for 1980 to 1999 (the authors report chi-square 23.23, 47 degrees of freedom, P = 0.9986).
  • Lifetime risk of death from pleural mesothelioma among the general male population, calculated with the 1960 life table, rose across birth cohorts. It peaked at 3.21 × 10⁻³ (95% CI 1.21 × 10⁻³ to 8.47 × 10⁻³) for the 1950 to 1959 birth cohort, then decreased somewhat for the 1955 to 1964 cohort.
  • Predicted total pleural mesothelioma deaths among Japanese males in 2000 to 2039: about 101,400.
  • Predicted deaths in 2030 to 2039 were 43,150, which is 21.0 times the 2,051 deaths observed in 1990 to 1999.
  • Predicted deaths peaked in 2030 to 2034.
  • The authors compared predicted deaths for 1995 to 2029 against population size, using European projections by Peto et al. 1999. Across countries the relationship was close to linear. Japan's data point was slightly lower than the linear relationship would predict.
• The authors' conclusion: The authors concluded that, because younger birth cohorts could not be included, the prediction very likely underestimates the number of deaths that will actually occur. They also concluded that it should be refined as updated data become available.
• Limitations the authors state:
  • Men born after 1964 could not be included, although they lived through Japan's period of high asbestos consumption.
  • Deaths before 1979 could not be used because the ICD-8 era death data were unreliable.
  • Pleural mesothelioma deaths for 1979 to 1994 were estimated by assuming that the 1995 to 2000 split between pleural mesothelioma and other pleural cancers also applied then. On that assumption, the authors reduced the older pleural cancer counts by 6.8%.
  • The comparison with other countries is limited because the countries' projections used different methods.
  • Citing Hodgson et al. 2005, the authors note that a simple birth-cohort model without asbestos consumption may not correctly predict deaths in later cohorts.

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, Mesothelioma, Pleural Mesothelioma.

Related studies

• Predictions of mortality from pleural mesothelioma in Italy: a model based on asbestos consumption figures supports results from age-period-cohort models — A. Marinaccio, F. Montanaro, et al. (2005)
• Estimation of the past and future burden of mortality from mesothelioma in France — A.G. Ilg, J. Bignon, et al. (1998)
• Future trends of mesothelioma mortality in Japan based on a risk function — T. Myojin, K. Azuma, et al. (2012)
• Mesothelioma risk and environmental exposure to asbestos: past and future trends in Japan — K. Azuma, I. Uchiyama, et al. (2009)
• An updated historical cohort mortality study of workers exposed to asbestos in a refitting shipyard, 1947-2007 — K. Tomioka, Y. Natori, et al. (2011)
• A historical cohort mortality study of workers exposed to asbestos in a refitting shipyard — N. Kurumatani, Y. Natori, et al. (1999)

Browse more research in American Journal of Industrial Medicine, or return to medical research.