Mesothelioma incidence seems to have leveled off in Sweden

Our plain-English summary of Mesothelioma incidence seems to have leveled off in Sweden, by K. Hemminki, X. Li (International Journal of Cancer, 2003).

The study

• Authors: K. Hemminki, X. Li
• Journal: International Journal of Cancer
• Published: 2003;103(1):145-6
• Type of article: Letter
• Cited by: 33 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Summary of the article

In this letter, the authors examined whether the incidence of pleural mesothelioma in Sweden had stopped rising. Sweden had drastically reduced asbestos imports in 1976 and had almost completely abolished asbestos use. The authors therefore expected it to be among the first countries to show a leveling off. They collected cases of pleural mesothelioma (ICD-7 code 162.2) from the Swedish Cancer Registry for 1961–2000 and calculated age-standardized incidence rates, adjusted to the European standard population, in 5-year periods. For men, incidence was 1.82/100,000 (95% CI 1.66–1.99) in 1991–95 and 1.79/100,000 (1.63–1.95) in 1996–2000. For women, the corresponding rates were 0.32 and 0.23/100,000. The rates for the two periods did not differ significantly. The difference in linear regression coefficients for annual rates between 1966–95 and 1996–2000 was reported as highly significant for men. Incidence decreased in the oldest age group, was stable among those aged 45–59, and appeared to increase somewhat among men aged 60–74. Assuming a background rate of 1–2 per million, the authors estimated that 2,030 of 2,190 male cases and about 350 female cases could be ascribed to asbestos up to 2000. They concluded that incidence appeared to have peaked in 1991–95, about 17 years after the reduction in imports. They urged cautious interpretation, because the leveling off might be transient, and called for monitoring of future data.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.

In plain English

This letter to the editor examined trends in pleural mesothelioma in Sweden, using Swedish Cancer Registry cases from 1961 to 2000. The authors calculated age-standardized rates in 5-year periods. For men, the rate was 1.82 per 100,000 (95% confidence interval 1.66 to 1.99) in 1991–95 and 1.79 (1.63 to 1.95) in 1996–2000. For women, the rates were 0.32 per 100,000 (0.26 to 0.38) and 0.23 (0.18 to 0.28). These differences were not statistically significant. The authors took this as a sign that the rise had leveled off, peaking in 1991–95. By age, incidence fell in the oldest men and women, was stable at ages 45–59, and appeared to rise somewhat among men aged 60–74. Using a background rate estimated elsewhere, the authors ascribed 2,030 of 2,190 male cases to asbestos up to 2000. Applying the same rate to women, they gave an asbestos-related excess of 350 cases, an estimate they called less accurate. They urged cautious interpretation. They noted the leveling off might be temporary and that some cases may reflect erionite exposure among Turkish immigrants.

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: Letter to the editor reporting a descriptive analysis of time trends in national cancer registry data
• Who was studied: Cases of pleural mesothelioma (ICD-7 code 162.2) recorded in the Swedish Cancer Registry, 1961–2000. There were 2190 male cases in total. The female total is implied as 504 in the authors' calculation.
• Exposure: No individual exposure data were analyzed. The authors related national trends to asbestos use in Sweden: crocidolite was prohibited in 1975 and asbestos imports were drastically reduced in 1976.
• Main results:
  • Men: age-standardized incidence was 1.82/100,000 (95% CI 1.66–1.99) in 1991–95, compared with 1.79/100,000 (95% CI 1.63–1.95) in 1996–2000.
  • Women: incidence was 0.32/100,000 (0.26–0.38) in 1991–95 and 0.23/100,000 (0.18–0.28) in 1996–2000.
  • The rates in the two periods did not differ significantly from each other, because the 95% confidence intervals overlapped.
  • For men, the difference in linear regression coefficients for annual incidence rates between 1966–95 and 1996–2000 was highly significant. The p-value is printed as 0.0006, but the comparison symbol is missing from the text.
  • By age group, incidence was decreasing in the oldest age group for men and women and was quite stable in the youngest group (45–59 years).
  • Among men aged 60–74, some increase appeared toward the last observation period. Among women of that age, rates fluctuated.
  • Assuming a background rate of 1–2 per million (160 background male cases over the study), the authors estimated that 2,030 of the 2190 male cases could be ascribed to asbestos up to 2000.
  • Applying the same background rate, the authors gave the asbestos-related excess among women as 350, calculated from 504 minus 160. They described this female estimate as less accurate.
• The authors' conclusion: The authors concluded that pleural mesothelioma incidence in Sweden appeared to have leveled off, with a maximum in 1991–95. They emphasized cautious interpretation and the need to observe future incidence data.
• Limitations the authors state:
  • Specific histology was not available after 1993, so cases were defined only by the registry code 162.2.
  • Some cases may be due to erionite exposure in Turkey among Turkish immigrants to Sweden.
  • Some underreporting was likely before the 1970s.
  • The leveling off might be transient, for example because of restructuring of asbestos-related industries such as shipbuilding.
  • The estimate of asbestos-related cases among women is less accurate than the estimate for men.

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, Pleural Mesothelioma, Cancer Registry, Incidence, Background Rate.

Related studies

• Pleural mesothelioma in Sweden: an analysis of the incidence according to the use of asbestos — B. Järvholm, A. Englund, et al. (1999)
• Incidence, mortality and survival in malignant pleural mesothelioma before and after asbestos in Denmark, Finland, Norway and Sweden — K. Hemminki, A. Försti, et al. (2021)
• Occupation and mesothelioma in Sweden: updated incidence in men and women in the 27 years after the asbestos ban — N. Plato, J.I. Martinsen, et al. (2016)
• Incidence and familial risk of pleural mesothelioma in Sweden: a national cohort study — J. Ji, J. Sundquist, et al. (2016)
• Explaining differences in incidence rates of pleural mesothelioma between Sweden and the Netherlands — A. Burdorf, B. Järvholm, et al. (2005)
• A Comparative Analysis of Lung Cancer Incidence and Tobacco Consumption in Canada, Norway and Sweden: A Population-Based Study — J. Chen (2023)

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