‘Danish Cohort’ and the unwillingness of the Editors of the BMJ to act responsibly

Reading the commentary in the British ‘Nature‘: “A tragedy of errors: Mistakes in peer-reviewed papers are easy to find but hard to fix” by David B. Allison, Andrew W. Brown, Brandon J. George, and Kathryn A. Kaiser, reminded me of the Danish Cohort update study published in 2011 in the British ‘BMJ‘.

Allison and colleagues elegantly presented not only the problem of low quality peer-review and the misuse of statistical tools but also the problem caused by editors of the journals.

In the “A tragedy of errors” Allison and colleagues list six problems:

  1. Editors are often unable or reluctant to take speedy and appropriate action
  2. Where to send expressions of concern is unclear
  3. Journals that acknowledged invalidating errors were reluctant to issue retractions
  4. Journals charge authors to correct others’ mistakes
  5. No standard mechanism exists to request raw data
  6. Informal expressions of concern are overlooked

This list clearly points towards the editors of the journals as those primarily responsible for non-retraction of the articles that were published due to the faulty and/or incompetent and/or biased peer-review.

The Danish Cohort update from 2011 (pdf) was severely criticized in a number of letters to the editor. pointing to serious flaws in the design of the study that, in essence, invalidated the conclusions made by the authors. I was one of the scientists who wrote to the editors of BMJ and, in my letter dated Dec. 3, 2011, I stated, among others:

“…This study has several design flaws that should prevent the authors from any conclusions concerning the impact of mobile phone use on the development of brain cancer…”

and I concluded that

“…flaws and shortcomings make this study unreliable and make impossible to draw any valid conclusions. The conclusions presented by the authors are not supported by the presented data….”

In spite of the number of valid complaints presented by a number of scientists, the flawed (=shoddy) article remains as a valid peer-reviewed scientific evidence.

Nothing happened. The BMJ editors did not take any action.

On February 25, 2013, I published an opinion in ‘The Scientist Magazine‘: “Scientific Peer Review in Crisis. The case of the Danish Cohort“. In this article I asked the question:

“…How is it possible that the British Medical Journal allowed such a poor quality peer review? Were the peer reviewers incompetent or did they have conflicts of interest? What was the involvement of the BMJ’s editors? Why, once alerted to serious design flaws by readers, have BMJ editors not taken any action?…”

and I called for either revision or retraction of the Danish Cohort update study:

“…In my opinion the Danish Cohort study should be retracted because no revision or rewriting can rescue it. The study is missing crucial data on exposure to cell phone radiation. Furthermore, an investigation should be launched to determine why such a flawed study was published. Was it peer reviewer and BMJ editor incompetence alone or was a conflict of interest among reviewers involved? (The authors of the study declared no conflicts of interest, but the original cohort was reportedly established with funding from a Danish phone company.) Answering these questions is important because it might help to avoid similar mistakes in the future…”

 and I explained why the correction or retraction is of a great importance:

“...It is clear to me that these flaws invalidate the conclusions of the Danish Cohort study. Peer-review failed, and a study that should never have got published due to its unfounded conclusions remains as a valid peer-reviewed article in the British Medical Journal. As long as the flawed study is not withdrawn it will be used by scientists and by decision makers to justify their actions—e.g. a reference to the Danish Cohort study was recently used as supporting evidence in failing to indicate a causal link between cell phone radiation and brain cancer by the US Government Accountability Office...”

Again, nothing happened. The BMJ editors did not take any action.

Recently, Dr. Christopher Portier Ch Portiercommented on the Danish Cohort update study of 2011. In his plenary lecture at the BioEM2015 Chris Portier stated that:

“…Danish Cohort study is useless for any decision making because of the serious misclassification of “exposures”…”.

The editors of the BMJ remain deaf. They did not take any action concerning the Danish Cohort update study of 2011. Neither correction nor retraction happened, thus far. As it stands now, the Danish Cohort update study of 2011 provides false, unsupported by the data, evidence on the possible causality link between exposures to cell phone radiation and brain cancer.

This misleading evidence from the Danish Cohort was recently used in the “European Code against Cancer 4th Edition: Ionising and non-ionising radiation and cancer” where it was stated [emphasis added DL]:

“…Case–control studies on mobile phone use and cancer have reported increased risks of glioma and acoustic neuroma in heavy users of mobile phones, based on self-reported mobile phone use [35,36]. Cohort studies have shown no associations, but had fewer data on heavy users [37,38]...

where as the reference #37 is used the Danish Cohort update study: [37] Frei P, Poulsen AH, Johansen C, Olsen JH, Steding-Jessen M, Schu¨ z J. Use of mobile phones and risk of brain tumours: update of Danish cohort study.
Br. Med. J. 2011;343:d6387.

As long as the uncorrected Danish Cohort remains as a valid peer-reviewed study, it will be used to provide false claims unsupported by the data presented by the authors.

Yet again, I call upon the editors of the BMJ to take an appropriate action to either request the authors to correct the flaws of the Danish Cohort study or to retract it.


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