Expected number of asbestos-related lung cancers in the Netherlands in the next two decades: a comparison of methods

Our plain-English summary of Expected number of asbestos-related lung cancers in the Netherlands in the next two decades: a comparison of methods, by S. Van der Bij, R.C. Vermeulen, L. Portengen, et al (Occupational and Environmental Medicine, 2016).

The study

• Authors: S. Van der Bij, R.C. Vermeulen, L. Portengen, K.G. Moons, H. Koffijberg
• Journal: Occupational and Environmental Medicine
• Published: 2016;73(5):342-9
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objectives: Exposure to asbestos fibres increases the risk of mesothelioma and lung cancer. Although the vast majority of mesothelioma cases are caused by asbestos exposure, the number of asbestos-related lung cancers is less clear. This number cannot be determined directly as lung cancer causes are not clinically distinguishable but may be estimated using varying modelling methods.

Methods: We applied three different modelling methods to the Dutch population supplemented with uncertainty ranges (UR) due to uncertainty in model input values. The first method estimated asbestos-related lung cancer cases directly from observed and predicted mesothelioma cases in an age-period-cohort analysis. The second method used evidence on the fraction of lung cancer cases attributable (population attributable risk (PAR)) to asbestos exposure. The third method incorporated risk estimates and population exposure estimates to perform a life table analysis.

Results: The three methods varied substantially in incorporated evidence. Moreover, the estimated number of asbestos-related lung cancer cases in the Netherlands between 2011 and 2030 depended crucially on the actual method applied, as the mesothelioma method predicts 17 500 expected cases (UR 7000-57 000), the PAR method predicts 12 150 cases (UR 6700-19 000), and the life table analysis predicts 6800 cases (UR 6800-33 850).

Conclusions: The three different methods described resulted in absolute estimates varying by a factor of ∼2.5. These results show that accurate estimation of the impact of asbestos exposure on the lung cancer burden remains a challenge.

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In plain English

This modelling study compared three ways to estimate future asbestos-related lung cancers in the Netherlands, 2011 to 2030. The first method projected mesothelioma deaths from Dutch death records, 1969 to 2010. It converted them using a published smoking-adjusted ratio for mixed fibres of 1.5 lung cancers per mesothelioma death (95% CI 1.1 to 2.0). The second method applied the share of lung cancers attributed to asbestos in an earlier Dutch study (11.6%, men aged 55 to 73, 1986 to 1990) to future lung cancers in men over 40, treating men born after 1970 as unexposed. It derived a separate 2.5% share for women. The third method used job-history exposure estimates from a Dutch cohort in a life table analysis. The methods estimated about 17 500, 12 150 and 6800 cases, with uncertainty ranges of roughly 7000 to 57 000, 6700 to 19 000 and 6800 to 33 850. The authors concluded that estimates varied by a factor of 2.5 and the preferred method depends on available evidence and context. They noted the ratio depends strongly on fibre type.

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 comparing three projection methods: a mesothelioma-ratio model based on age-period-cohort analysis, a population attributable risk (PAR) model, and a life table model
• Who was studied: The Dutch general population, men and women, with projections for 2011 to 2030. Inputs included mesothelioma deaths recorded in 1969 to 2010 and job histories for 4568 participants in a subcohort of the Netherlands cohort study (NLCS).
• Exposure: Asbestos exposure in general. Model 1 used a published smoking-adjusted mesothelioma-to-lung-cancer ratio for mixed asbestos fibres. Model 3 estimated cumulative occupational exposure in fibre-years (f-y/mL) using a Finnish job-exposure matrix (FINJEM), applied to jobs held before 1990.
• Main results:
  • The ratio used in model 1 was 1.5 asbestos-related lung cancers per mesothelioma death (95% CI 1.1 to 2.0), for mixed fibres.
  • Mesothelioma model: about 17 500 asbestos-related lung cancers between 2011 and 2030. Annual numbers were expected to rise until 2022 and decline thereafter.
  • PAR model: a PAR of 11.6%, taken from Dutch men aged 55 to 73 in 1986 to 1990, was applied to lung cancers in men over 40.
  • PAR model: people born after 1970 were assumed never exposed and given zero PAR. Age groups containing people born both before and after 1970 received a linearly interpolated PAR.
  • PAR model: no reliable PAR was available for Dutch women, so a ratio-based approach was used, which gave a PAR of 2.5% for women.
  • PAR model: annual cases fell from 826 in 2011 to 371 in 2030, about 12 150 in total.
  • Life table model: annual cases fell from 459 in 2011 to 207 in 2030, about 6800 in total.
  • Estimated in 2010: about 25% of men aged 50 or older and fewer than 1% of women aged 50 or older might have been exposed to asbestos.
  • Uncertainty range for the mesothelioma model, assuming a ratio between 1:0.6 and 1:4.9: around 7000 to 57 000 cases.
  • Uncertainty range for the PAR model, assuming a PAR from 5.7% to 19%: around 6700 to 19 000 cases.
  • Uncertainty range for the life table model, from the original exposure estimates up to exposures calibrated against mesothelioma: around 6800 to 33 850 cases.
• The authors' conclusion: The authors concluded that the three methods gave estimates varying by a factor of 2.5, and that the preferred method depends on the available evidence and context.
• Limitations the authors state:
  • All models assumed that people born after 1970 had negligible risk, so actual future cases may be marginally higher.
  • The greatest uncertainty in model 1 is the mesothelioma-to-lung-cancer ratio, which depends strongly on fibre type.
  • Applying the PAR from men aged 55 to 73 to all men over 40 may be questionable, because younger men likely had lower exposure.
  • Future lung cancer rates may be 10 to 15% lower than assumed because of declining smoking.
  • The life table model may be biased by inaccurate job histories and exposure estimates. Calibration suggested that exposures or mesothelioma risks needed to be about three times higher.

Topics

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

Medical terms in this study, explained in our Lexicon: Lung Cancer, Mesothelioma, Asbestos Exposure, Population Attributable Fraction (PAF).

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