Enduring health effects of asbestos use in Belgian industries: a record-linked cohort study of cause-specific mortality (2001-2009)

Our plain-English summary of Enduring health effects of asbestos use in Belgian industries: a record-linked cohort study of cause-specific mortality (2001-2009), by L. Van den Borre, P. Deboosere (BMJ Open, 2015).

The study

• Authors: L. Van den Borre, P. Deboosere
• Journal: BMJ Open
• Published: 2015;5(6):e007384
• Cited by: 25 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Objective: To investigate cause-specific mortality among asbestos workers and potentially exposed workers in Belgium and evaluate potential excess in mortality due to established and suspected asbestos-related diseases.

Design: This cohort study is based on an individual record linkage between the 1991 Belgian census and cause-specific mortality information for Flanders and Brussels (2001-2009).

Setting: Belgium (Flanders and Brussels region).

Participants: The study population consists of 1,397,699 male workers (18-65,years) with 72,074 deaths between 1 October 2001 and 31 December 2009. Using a classification of high-risk industries, mortality patterns between 2056 asbestos workers, 385,046 potentially exposed workers and the working population have been compared.

Outcome Measures: Standardised mortality ratios (SMRs) and 95% CIs are calculated for manual and non-manual workers.

Results: Our findings show clear excess in asbestos-related mortality in the asbestos industry with SMRs for mesothelioma of 4071 (CI 2327 to 6611) among manual workers and of 4489 (CI 1458 to 10,476) among non-manual workers. Excess risks in asbestos-related mortality are also found in the chemical industry, the construction industry, the electrical generation and distribution industry, the basic metals manufacturing industry, the metal products manufacturing industry, the railroad industry, and the shipping industry. Oral cancer mortality is significantly higher for asbestos workers (SMR 383; CI 124 to 894), railroad workers (SMR 192; CI 112 to 308), shipping workers (SMR 172; CI 102 to 271) and construction workers (SMR 125; CI 100 to 153), indicating a possible association with occupational asbestos exposure. Workers in all four industries have elevated mortality rates for cancer of the mouth. Only construction workers experience significantly higher pharyngeal cancer mortality (SMR 151; CI 104 to 212).

Conclusions: The study identifies vulnerable groups of Belgian asbestos workers, demonstrating the current-day health repercussions of historical asbestos use. Results support the hypothesis of a possible association between the development of oral cancer and occupational asbestos exposure.

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In plain English

This cohort study linked the 1991 Belgian census to death records for Flanders and Brussels from October 2001 to December 2009. It followed 1,397,699 men aged 18 to 65 working in 1991, of whom 72,074 died. With no individual exposure data, the authors grouped workers by industry: 2,056 asbestos-industry workers, 385,046 potentially exposed workers, and all other workers. Results were given as standardised mortality ratios (SMRs). An SMR of 100 meant deaths equalled the number expected from the rates of workers in all other industries. Mesothelioma deaths were about 41 times expected among manual asbestos-industry workers (SMR 4071; 95% CI 2327 to 6611) and 45 times among non-manual workers (SMR 4489; CI 1458 to 10,476). Excess asbestos-related deaths were also found in seven other industries, including construction, shipping, railroads and electricity generation and distribution. Oral cancer deaths were significantly higher among manual workers in the asbestos, railroad, shipping and construction industries. The authors concluded that their results support a possible association between occupational asbestos exposure and oral cancer. They noted that smoking, alcohol and other confounders could not be taken into account.

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: Record-linked cohort study (1991 census linked to cause-specific death certificate data, 2001-2009), using standardised mortality ratios calculated against workers in all other industries
• Who was studied: 1,397,699 occupationally active men aged 18-65 in Flanders and the Brussels Capital Region at the 1991 Belgian census, with 72,074 deaths between 1 October 2001 and 31 December 2009. The groups were 2,056 asbestos workers, 385,046 potentially exposed workers, and 1,010,597 other workers as the reference group.
• Exposure: Employment in 1991 in high-risk industries, with no individual exposure measurements. Category A was the asbestos industry (asbestos cement and asbestos products manufacturing). Category B was 10 industries with potential exposure (automotive, chemical, construction, electricity generation and distribution, electrotechnical products, basic metals, metal products, railroad, shipping, textile). Manual and non-manual workers were analysed separately.
• Main results:
  • Mesothelioma among asbestos-industry workers: SMR 4071 (CI 2327 to 6611) for manual workers and 4489 (CI 1458 to 10 476) for non-manual workers.
  • Lung cancer was higher than expected among manual asbestos-industry workers (SMR 175; CI 108 to 268).
  • Laryngeal cancer among non-manual asbestos-industry workers: SMR 1425 (CI 173 to 5148).
  • Significant excess asbestos-related mortality was found in the asbestos industry and in seven of the selected industries: chemical, construction, electrical generation and distribution, basic metals, metal products, railroad and shipping.
  • Among non-manual construction workers, the mesothelioma SMR was 260 (CI 149 to 422) and the asbestosis SMR was 843 (CI 102 to 3043).
  • No significant excess asbestos-related mortality was found in the automotive, textile or electrotechnical industries.
  • Oral cancer mortality was significantly higher among manual workers: asbestos industry SMR 383 (CI 124 to 894), railroad SMR 192 (CI 112 to 308), shipping SMR 172 (CI 102 to 271) and construction SMR 125 (CI 100 to 153).
  • Only construction workers had significantly higher pharyngeal cancer mortality (SMR 151; CI 104 to 212).
• The authors' conclusion: The authors concluded that the study identifies vulnerable groups of Belgian asbestos workers and that the results support the hypothesis of a possible association between oral cancer and occupational asbestos exposure.
• Limitations the authors state:
  • No asbestos exposure data were available; exposure was assumed from industry.
  • Occupational information was available for only one point in time.
  • Potential confounders such as smoking and alcohol could not be considered.
  • Only actively employed workers were studied, so healthy worker effects may bias the results.
  • Asbestosis deaths may be underestimated because the analysis used only the underlying cause of death.
  • The number of workers at risk is overestimated because exposure was assigned by industry.
  • The results may underestimate the true influence of occupational asbestos exposure.

Topics

Medical terms in this study, explained in our Lexicon: Cohort Study, Mesothelioma, Asbestos Exposure, Pharyngeal Cancer.

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