Quality of evidence must guide risk assessment of asbestos, by Lenters, V; Burdorf, A; Vermeulen, R; Stayner, L; Heederik, D

Our plain-English summary of Quality of evidence must guide risk assessment of asbestos, by Lenters, V; Burdorf, A; Vermeulen, R; Stayner, L; Heederik, D, by J.T. Hodgson (The Annals of Occupational Hygiene, 2013).

The study

• Author: J.T. Hodgson
• Journal: The Annals of Occupational Hygiene
• Published: 2013;57(5):670-4
• Type of article: Letter, Comment
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This is a letter to the editor, not a new study of workers. The author re-checked the statistics of a 2011 meta-analysis by Lenters and colleagues. That meta-analysis of 19 asbestos and lung cancer studies reported that those with better exposure assessment gave higher estimates of risk per unit of exposure. The author used permutation tests, which repeatedly reshuffle the studies at random. With no constraints, the chance that all five quality criteria would show higher risk estimates was 0.054. When Study 3, which met no quality criteria, was always kept out of the higher-quality groups, that chance rose to 38%. When Study 4 was also always included, it rose to 72%. As lower-quality studies were removed, the estimates mostly rose, with some downward steps; this trend was expected given that Study 4 was in the final group. The author noted that fibre type was most associated with risk per unit of exposure in the original analysis (P = 0.06), though not highly significant. The author concluded that the original main finding was less robust than claimed and should be interpreted cautiously.

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 presenting a statistical re-analysis (permutation tests) of a published meta-analysis
• Who was studied: The 19 asbestos and lung cancer studies included in the 2011 meta-analysis by Lenters et al.
• Exposure: Asbestos exposure and lung cancer risk per unit of exposure (KL), with fibre type classified as chrysotile versus amphibole and mixed
• Main results:
  • With no constraint on how studies were randomly selected, the probability that all five quality criteria would give higher KL estimates was 0.054. This is somewhat more than the 1 in 32 (0.031) expected if the five criteria were independent.
  • When random groups were constrained to exclude Study 3 (which met no quality criteria), more than 70% of replicates gave a higher KL for each criterion. There was a 38% chance that all five criteria would give a higher estimate.
  • When random groups were constrained to include Study 4, the chance that all five criteria would give higher KL estimates was 14%.
  • With both constraints (including Study 4 and excluding Study 3), the probability of a higher estimate for all five criteria was 72%.
  • As lower-quality studies were successively excluded, the pooled KL increased nearly but not always at every step. This near-monotonic increase was what would be expected given that Study 4 was in the final group.
  • Citing the original meta-analysis, the author noted that fibre type was the variable most highly associated with KL, the risk per unit of exposure (P = 0.06).
  • Citing the original meta-analysis, the author also noted that two criteria considered individually, coverage and job histories, showed near significant relationships with KL (P = 0.08).
  • Study 19 (Gustavsson et al., 2002) met four of the five quality criteria. Its exposure-response estimate was nearly 10 times higher than the next highest study and more than 100 times the average of the 19 studies.
• The authors' conclusion: The author concluded that the main finding of the original meta-analysis was less robust than claimed and should be interpreted cautiously.
• Limitations the authors state:
  • The author stated that the fibre-type association is not highly significant and may also be sensitive to particular studies.
  • The author stated that, because the evidence is heterogeneous and apparently inconsistent, no statistical conclusion on this topic can be as clear and robust as desired.

Topics

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

Related studies

• Quality of evidence must guide risk assessment of asbestos, by Lenters, V; Burdorf, A; Vermeulen, R; Stayner, L; Heederik, D — D.W. Berman, B.W. Case (2013)
• Quality of evidence must guide risk assessment of asbestos — V. Lenters, A. Burdorf, et al. (2012)
• Overreliance on a single study: there is no real evidence that applying quality criteria to exposure in asbestos epidemiology affects the estimated risk — D.W. Berman, B.W. Case (2012)
• A ban on asbestos must be based on a comparative risk assessment — M. Camus (2001)
• An air quality data analysis system for interrelating effects, standards, and needed source reductions: Part 13--Applying the EPA Proposed Guidelines for Carcinogen Risk Assessment to a set of asbestos lung cancer mortality data — R.I. Larsen (2003)
• Reply: response to the letter by Drs Berman and Case — D. Heederik, V. Lenters, et al. (2013)

Browse more research in The Annals of Occupational Hygiene, or return to medical research.