Occupational characteristics of cases with asbestos-related diseases in The Netherlands

Our plain-English summary of Occupational characteristics of cases with asbestos-related diseases in The Netherlands, by A. Burdorf, M. Dahhan, P. Swuste (The Annals of Occupational Hygiene, 2003).

The study

• Authors: A. Burdorf, M. Dahhan, P. Swuste
• Journal: The Annals of Occupational Hygiene
• Published: 2003;47(6):485-92
• Cited by: 39 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objective: To describe the occupational background of cases with an asbestos-related disease and to present overall mesothelioma risks across industries with historical exposure to asbestos.

Methods: For the period 1990-2000, cases were collected from records held by two law firms. Information on jobs held, previous employers, activities performed and specific products used were obtained from patients themselves or next of kin. Branches of industry and occupations were coded and the likelihood of asbestos exposure was assessed. For each branch of industry, the overall risk of mesothelioma was calculated from the ratio of the observed number of mesothelioma cases and the cumulative population-at-risk in the period 1947-1960. In order to compare mesothelioma risks across different industries, risk ratios were calculated for the primary asbestos industry and asbestos user industries relative to all other branches of industry.

Results: In total, 710 mesotheliomas and 86 asbestosis cases were available. The average latency period was approximately 40 yr and the average duration of exposure was 22 yr. Ship building and maintenance contributed the largest number of cases (27%), followed by the construction industry (14%), the insulation industry (12%), and the navy and army, primarily related to ship building and maintenance (5%). In the insulation industry, the overall risk of mesothelioma was 5 out of 100 workers, and in the ship building industry, 1 out of 100 workers. The construction industry had an overall risk comparable with many other asbestos-using industries (7 per 10,000 workers), but due to its size claimed many mesothelioma cases.

Conclusion: The majority of cases with asbestos-related diseases had experienced their first asbestos exposure prior to 1960. For cases with first asbestos exposure after 1960, a shift was observed from the primary asbestos industry towards asbestos-using industries, such as construction, petroleum refining, and train building and maintenance. Due to the long latency period, asbestos exposure from 1960 to 1980 will cause a considerable number of mesothelioma cases in the next two decades.

In plain English

This Dutch study described 796 people with asbestos-related disease (710 with mesothelioma, 86 with asbestosis) whose cases were in the files of two law firms in 1990–2000. Work histories came from interviews with patients or their next of kin. The mean time from first exposure to diagnosis was 40.5 years for mesothelioma and 37.0 years for asbestosis, and exposure lasted 21.4 years on average. Ship building and maintenance accounted for 27% of cases, construction 14%, insulation 12%, and navy and army 5%. Using estimated male workforce sizes for 1947–1960, the authors calculated an overall mesothelioma risk of 5 per 100 workers in insulation, 1 per 100 in ship building, and 14 per 100,000 in all other industries. Among cases first exposed in 1960 or later, more came from industries using asbestos products, such as construction. The authors concluded that exposure from 1960 to 1980 will cause a considerable number of mesothelioma cases in the next two decades. They cautioned that law-firm records may be biased and that the risk estimates have limited precision.

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: Descriptive case series built from law firm records, with estimated overall mesothelioma risks and risk ratios by branch of industry
• Who was studied: 796 cases of asbestos-related disease (710 mesothelioma, 86 asbestosis; 771 men and 25 women) in the files of two Dutch law firms, 1990–2000. According to the authors, these firms handled almost all asbestos-related legal suits against employers. The mesothelioma claimants were 0.19 of all mesothelioma cases registered in 1990–1998.
• Exposure: Lifetime occupational asbestos exposure, assessed by the authors from interview-based work histories (jobs, employers, activities, products). Cases were grouped as primary asbestos industry, industries using asbestos-containing products, and all other industries. The authors also identified household and environmental sources. Mean exposure duration was 21.4 years. In the discussion, the authors stated that at least 90% of the asbestos was chrysotile, and that insulation and ship building were the primary users of crocidolite and amosite.
• Main results:
  • Mean latency from first exposure to diagnosis was 37.0 years for asbestosis cases and 40.5 years for mesothelioma cases.
  • Mean age at death was significantly lower among asbestosis cases (59.4 years) than among mesothelioma cases (62.9 years).
  • Year of first exposure (known for 94% of cases): 11% before 1940, 24% in the 1940s, 38% in the 1950s, 20% in the 1960s, and 6% in 1970 or later.
  • By industry, ship building and maintenance contributed 27% of cases, construction 14%, insulation 12%, and navy and army 5%.
  • Among the 710 mesothelioma cases, five had household exposure and three had environmental exposure.
  • The primary asbestos industry plus ship building accounted for 49% of cases first exposed before 1960, but only 24% of cases first exposed in 1960 or later. Construction's share rose from 11% to 21%.
  • Estimated overall mesothelioma risk among men: 5 out of 100 workers in the insulation industry, 1 out of 100 in ship building, and 14 per 100,000 in the reference group of all other industries.
  • Risk ratios relative to all other industries: insulation 328, ship building 83, petroleum refining 24, train building and maintenance 15, navy and army 13, stone, glass and cement 9. The lowest were public administration (1.9) and food products manufacturing (0.9).
  • Construction had a risk comparable with many other asbestos-using industries (73 per 100,000 in Table 5, risk ratio 5.1), but because of its size it accounted for many mesothelioma cases.
• The authors' conclusion: The authors concluded that most cases were first exposed before 1960. For cases first exposed after 1960, they saw a shift from the primary asbestos industry to asbestos-using industries such as construction, petroleum refining, and train building and maintenance. They expected exposure from 1960 to 1980 to cause a considerable number of mesothelioma cases in the next two decades.
• Limitations the authors state:
  • Using lawyers' records may have caused selection bias. Younger people and men are more likely to sue: 60% of the mesothelioma cases were 65 or younger, against 40% expected from the Cancer Registry.
  • This selection may have led to an underestimate of the share of household and environmental cases.
  • The risk estimates are very sensitive to the assumptions behind the numerator and denominator, so they have limited precision.
  • The overall risks are not lifetime risks among exposed workers. The population at risk included unexposed workers, which dilutes the risk in industries such as construction and stone, glass and cement.
  • Latency periods may be overestimated, because people exposed before 1960 who had shorter latencies would have died before the study period began.

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, Asbestos Exposure, Latency.

Related studies

• Asbestos, asbestos-related diseases, and compensation claims in The Netherlands — P. Swuste, A. Burdorf, et al. (2004)
• Linking expert judgement and trends in occupational exposure into a job-exposure matrix for historical exposure to asbestos in the Netherlands — P. Swuste, M. Dahhan, et al. (2008)
• A history of awareness of asbestos disease and the control of occupational asbestos exposures in The Netherlands — L. Burdorf, P.H. Swuste, et al. (1991)
• Comparison of expert and job-exposure matrix-based retrospective exposure assessment of occupational carcinogens in The Netherlands Cohort Study — N.S. Offermans, R. Vermeulen, et al. (2012)
• Occupational asbestos exposure and risk of pleural mesothelioma, lung cancer, and laryngeal cancer in the prospective Netherlands cohort study — N.S. Offermans, R. Vermeulen, et al. (2014)
• Expected number of asbestos-related lung cancers in the Netherlands in the next two decades: a comparison of methods — S. Van der Bij, R.C. Vermeulen, et al. (2016)

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