Response to letter by Farioli et al

Our plain-English summary of Response to letter by Farioli et al, by A. Reid, P. Franklin, G. Berry, et al (Occupational and Environmental Medicine, 2019).

The study

• Authors: A. Reid, P. Franklin, G. Berry, S. Peters, N. Sodhi-Berry, F. Brims, A.W. Musk, N.H. de Klerk
• Journal: Occupational and Environmental Medicine
• Published: 2019;76(5):356
• Type of article: Letter, Comment
• Read it: PubMed · Publisher

In plain English

This is a letter, not a new research study. The authors answered Farioli and colleagues' letter criticising their earlier paper. That paper compared malignant mesothelioma rates between people first exposed to blue asbestos at Wittenoom, Western Australia, as children and as adults. They reported that models with terms for age at first exposure showed a marked increase at early ages, then levelling off to a slighter increase. These models fitted the data much better (P=0.0006). The table and figure were available on request, not printed. Repeating their table 3 with age standardisation gave a quite different overall picture: children had lower rates in only three of the five time-since-exposure groups. The authors said this table could still be misleading; their main results remained those in table 4. They omitted one interaction term because it made little difference, and left out interactions with sex and age at first exposure for ease of interpretation. Citing the Western Australian Mesothelioma Registry, they were confident there was little or no misclassification of their study's outcome. They maintained they had clearly shown no additional risk for those first exposed as children.

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 (authors' reply to criticism of their earlier published study)
• Who was studied: Refers to the authors' earlier study of people first exposed as children compared with people first exposed as adults to blue asbestos at Wittenoom, Western Australia. The letter gives no numbers of people.
• Exposure: Non-occupational exposure to blue asbestos at Wittenoom, Western Australia, first occurring in childhood or in adulthood
• Main results:
  • Models including fractional polynomial terms for age at first exposure showed a marked increase at early ages, then levelling off to a slighter increase with age at first exposure. The table and figure were not printed and were said to be available on request.
  • These fractional polynomial models fitted the data much better (P=0.0006)
  • When table 3 of the original paper was repeated with direct age standardisation (Segi World population, 10-year age groups), the overall picture was quite different. Children had lower rates in only three of the five time-since-exposure groups.
  • The authors did not present the interaction term because it made little difference to the exposure effect or to the model fit
  • An original version of table 4 included interactions with sex and with age at first exposure. These were left out of the final version for ease of interpretation.
• The authors' conclusion: The authors maintained that they had shown clearly there was no additional mesothelioma risk in people first exposed as children. They said their principal results remain those in table 4 of the original paper. They were confident there was little or no misclassification of their study's mesothelioma outcome.
• Limitations the authors state:
  • The authors said the age-standardised table could still be misleading, because it groups time since first exposure into only five categories while risk increases within each group
  • The authors acknowledged that their own earlier work found age effects on mesothelioma incidence with longer follow-up

Topics

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

Related studies

• Are children more vulnerable to mesothelioma than adults? A comparison of mesothelioma risk among children and adults exposed non-occupationally to blue asbestos at Wittenoom — A. Reid, P. Franklin, et al. (2018)
• Response to Kottek and Kilpatrick, 'Estimating Occupational Exposure to Asbestos in Australia' — S. Peters, S.C. van Oyen, et al. (2016)
• Migration and work in postwar Australia: mortality profile comparisons between Australian and Italian workers exposed to blue asbestos at Wittenoom — A. Reid, E. Merler, et al. (2018)
• Mesothelioma risk after 40 years since first exposure to asbestos: a pooled analysis — A. Reid, N.H. de Klerk, et al. (2014)
• Response to Letter to the Editor Regarding "Ambient Asbestos Fiber Concentrations and Long-Term Trends in Pleural Mesothelioma Incidence Between Urban and Rural Areas in the United States (1973-2012)" by Finkelstein — K.A. Keeton, M.E. Glynn, et al. (2018)
• Response to a letter to the editor by Dr. Murray M. Finkelstein regarding the article by Finley et al. (2012) — B.L. Finley, J.S. Pierce, et al. (2013)

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