Reply: response to the letter by Drs Berman and Case

Our plain-English summary of Reply: response to the letter by Drs Berman and Case, by D. Heederik, V. Lenters, R. Vermeulen (The Annals of Occupational Hygiene, 2013).

The study

• Authors: D. Heederik, V. Lenters, R. Vermeulen
• Journal: The Annals of Occupational Hygiene
• Published: 2013;57(5):675-7
• Type of article: Letter, Comment
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This is a reply letter, not a new study. It contains no new data. The authors defended their 2011 meta-analysis of occupational asbestos exposure and lung cancer against letters by Berman and Case and by Hodgson. They restated that ignoring the quality of exposure assessment may bias estimates of how much more cancer-causing one fibre type is than another. They agreed that fibre type is important, noting that most asbestos mined is chrysotile. They acknowledged that Hodgson's added analyses indicated a somewhat stronger effect of fibre type than of study quality. They cited a separate meta-analysis by van der Bij and colleagues that, using flexible modelling, found smaller and non-significant differences between fibre types at low exposures. They also argued that a 2002 Swedish case-control study by Gustavsson and colleagues stands out but cannot be called aberrant from its steep slope alone. The authors concluded that exposure assessment quality has received too little attention and that meta-analyses should be transparent about its effect. They stated that their quality criteria were not definitive.

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: Reply letter to the editor in a scientific debate (no new data or analysis)
• Who was studied: No people were studied. The letter responds to criticism from Berman and Case (2013) and Hodgson (2013) of the authors' 2011 meta-analysis published in Environmental Health Perspectives.
• Exposure: Occupational asbestos exposure in relation to lung cancer. The debate concerns fibre type (including chrysotile) versus the quality of exposure assessment.
• Main results:
  • The authors argued that ignoring exposure assessment quality may bias the estimated difference in cancer-causing potency between fibre types.
  • The authors agreed that fibre type is important, noting that most asbestos mined is chrysotile.
  • The authors reported that Hodgson's additional permutation analyses indicated a somewhat stronger effect of fibre type than of study quality.
  • The authors cited a separate meta-analysis (van der Bij et al., 2013). Using flexible modelling, it found smaller and non-significant differences between fibre types at the low exposure range.
  • The authors objected to the Berman and Crump (2008) approach of widening confidence limits according to study quality.
  • The authors disagreed that contrast in exposure measures only statistical power and not study quality.
  • The authors argued that the Gustavsson (2002) case-control study stands out, but that it cannot be judged aberrant from its high exposure-response slope alone.
  • The authors noted that a new study of Chinese chrysotile textile workers (Wang et al., 2013) had a relatively steep exposure-response relation, but that its quality still needs to be established.
• The authors' conclusion: The authors concluded that exposure assessment quality has received too little attention compared with fibre type, and that meta-analyses should evaluate and be transparent about the effect of quality.
• Limitations the authors state:
  • The authors stated that their quality criteria were a 'proof of principle' exercise, not a definitive set.
  • The authors stated that all the analyses in the debate assumed linear exposure-response relations, which may not hold.

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 — V. Lenters, A. Burdorf, et al. (2012)
• Letter to the editor: "Comparing milled fiber, Quebec ore, and textile factory dust: has another piece of the asbestos puzzle fallen into place?" by D. Wayne Berman — J.M. Dement, L.T. Stayner (2010)
• 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)
• Quality of evidence must guide risk assessment of asbestos, by Lenters, V; Burdorf, A; Vermeulen, R; Stayner, L; Heederik, D — J.T. Hodgson (2013)
• 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)
• Reply to letter by Nolan and colleagues--re: the carcinogenicity of New York state talc dusts in humans — M. Finkelstein (2013)

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