Recent mortality from pleural mesothelioma, historical patterns of asbestos use, and adoption of bans: a global assessment

Our plain-English summary of Recent mortality from pleural mesothelioma, historical patterns of asbestos use, and adoption of bans: a global assessment, by K. Nishikawa, K. Takahashi, A. Karjalainen, et al (Environmental Health Perspectives, 2008).

The study

• Authors: K. Nishikawa, K. Takahashi, A. Karjalainen, C.P. Wen, S. Furuya, T. Hoshuyama, M. Todoroki, Y. Kiyomoto, D. Wilson, T. Higashi, M. Ohtaki, G. Pan, G. Wagner
• Journal: Environmental Health Perspectives
• Published: 2008;116(12):1675-80
• Cited by: 74 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: In response to the health risks posed by asbestos exposure, some countries have imposed strict regulations and adopted bans, whereas other countries have intervened less and continue to use varying quantities of asbestos.

Objectives: This study was designed to assess, on a global scale, national experiences of recent mortality from pleural mesothelioma, historical trends in asbestos use, adoption of bans, and their possible interrelationships.

Methods: For 31 countries with available data, we analyzed recent pleural mesothelioma (International Classification of Diseases, 10th Revision) mortality rates (MRs) using age-adjusted period MRs (deaths/million/year) from 1996 to 2005. We calculated annual percent changes (APCs) in age-adjusted MRs to characterize trends during the period. We characterized historical patterns of asbestos use by per capita asbestos use (kilograms per capita/year) and the status of national bans.

Results: Period MRs increased with statistical significance in five countries, with marginal significance in two countries, and were equivocal in 24 countries (five countries in Northern and Western Europe recorded negative APC values). Countries adopting asbestos bans reduced use rates about twice as fast as those not adopting bans. Turning points in use preceded bans. Change in asbestos use during 1970-1985 was a significant predictor of APC in mortality for pleural mesothelioma, with an adjusted R(2) value of 0.47 (p < 0.0001).

Conclusions: The observed disparities in global mesothelioma trends likely relate to country-to-country disparities in asbestos use trends.

In plain English

This was an ecologic study comparing whole countries, not individual people. Using World Health Organization death records for men in 31 countries, the authors calculated age-adjusted death rates from pleural mesothelioma for 1996 to 2005, and the yearly percent change in those rates. They compared these with each country's per capita asbestos use and its ban status. The United Kingdom had the highest rate, 31.1 deaths per million per year. The median across countries was 7.8. Rates rose with statistical significance in five countries (Japan, Croatia, Hungary, Argentina and Brazil) and with marginal significance in two (Germany and Australia). In the other 24 countries the trend was equivocal. Countries adopting bans cut asbestos use about twice as fast as others, but declines in use began before the first bans. Among the periods tested, the change in asbestos use during 1970 to 1985 best predicted the recent mortality trend (adjusted R2 0.47, p less than 0.0001). The authors concluded that differences in mesothelioma trends likely relate to differences in asbestos use trends. They cautioned that the relationships are ecologic and that the exposure measure was crude.

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: Ecologic (country-level) study comparing national mortality trends with historical per capita asbestos use and ban status
• Who was studied: Men in 31 countries with available WHO mortality data, 1996 to 2005. Pleural mesothelioma was defined as ICD-10 C45.0 (pleura) plus C45.9 (unspecified mesothelioma). Countries needed at least 4 years of ICD-10 data.
• Exposure: National per capita asbestos use (kilograms per capita per year) from U.S. Geological Survey data, defined as production plus import minus export, together with national ban status (early-ban by 1995, late-ban 1996 to 2006, no-ban). Fiber types were not distinguished.
• Main results:
  • Period mortality from male pleural mesothelioma was highest in the United Kingdom, 31.1 deaths per million per year. The global median was 7.8 deaths per million per year.
  • Mortality trends showed statistically significant increases in five countries, marginally significant increases in two countries, and equivocal results in 24 countries. The global median annual percent change was 4.5% per year. Negative values were recorded in five countries of Northern and Western Europe.
  • Annual percent changes in the significant countries were Japan 3.9 (2.6 to 5.2), Croatia 11.0 (2.7 to 20.0), Hungary 11.0 (3.3 to 19.3), Argentina 8.9 (3.3 to 14.7) and Brazil 9.0 (0.1 to 18.7). The marginally significant countries were Germany 3.3 (–0.8 to 7.6) and Australia 4.6 (–0.6 to 10.1). The United States had an equivocal 0.8 (–2.4 to 4.1).
  • While adopting bans, the early-ban group reduced use at –8.3% per year, from 2.4 kg per capita per year in 1983 to less than 0.01 in 1995. Over the same period, the late-ban group reduced use at –4.1% per year and the no-ban group at –5.2% per year.
  • While adopting bans, the late-ban group reduced use at –10.7% per year, from 0.7 kg per capita per year in 1996 to 0.2 in 2003. The no-ban group reduced use at –4.9% per year over the same period, so the late-ban group's reduction rate was 2.2-fold quicker.
  • The no-ban group had the lowest peak use but currently maintains the highest level of asbestos use, at 0.4 kg per capita per year.
  • In countries with early and high use, downturns in asbestos use preceded the earliest bans.
  • Of all periods tried, the change in asbestos use during 1970 to 1985 was the strongest predictor of the recent mortality trend (29 countries, adjusted R2 0.47, p less than 0.0001). Regressions were weighted by male population size. Larger historical increases in use were associated with larger recent increases in mortality.
• The authors' conclusion: The authors concluded that the observed disparities in global mesothelioma trends are likely related to country-to-country disparities in asbestos use trends. They also said the study period was probably too early to observe the full effects of bans.
• Limitations the authors state:
  • Exposure was measured with a crude indicator: asbestos use per capita, for sparse years with limited data.
  • 'Bans' entailed varying restrictions on use that could not be measured.
  • No distinctions were available between asbestos fiber types.
  • Mortality data were limited to 31 countries. Developing countries likely lack well-developed surveillance systems to assure data quality.
  • The relationships are ecologic, at the national level only, so all findings should be interpreted cautiously.
  • The study period was inadequate to depict trends in many countries. Countries with data recorded only under ICD-9 (for example Italy) had to be excluded.
  • Increasing trends in low-mortality countries could be explained by improved disease recognition.
  • The latency in the best model was only 22.5 years, so the relationship may reflect only early effects.

Topics

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

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Asbestos Exposure, Statistical Significance, Mesothelioma.

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