Published scientific papers are a source of inspiration when writing this column. However they are also frequently a source of frustration.
A piece of science well reported can be very helpful in furthering our understanding of diseases. However, many published papers appear to be increasingly written to support established opinions rather than providing impartial scientific information.
Possibly I am not the only person who feels this as in one veterinary journal the editorial effectively tells authors how to write papers. In particular there are several paragraphs on bias, calling for a discussion section that presents data in the context of the published work and expert opinion of the time. In particular it states: ‘Authors are well advised to refrain from expressing opinion or presenting their data in a light that favours their intended interpretation.’
Fortunately none of this applies to journalism, so you can be sure AVV represents the personal views and interpretation that suits the author’s theories! But, enough of this generalisation what about some examples to illustrate what rattled my cage?
In just one regular veterinary publication there were no less than three reports that raised eyebrows. They were provided as Continuing Professional Development (CPD) and were aimed at the general practitioner.
One covered a case of a dog with a lung lobe that had twisted on its axis blocking the airway and blood supply to the lung lobe. In my experience these are rare and this case occurred in Israel. Nothing much controversial in the case itself but the fact that it occurred in a Pug was expanded upon in some detail.
The author states how lung lobe torsion in Pugs occurs most often in young males. A possible explanation suggests a cartilage hypoplasia giving airway instability in brachycephalic dog breeds. So now in just a few words this has been suggested as a conformational defect in all short nosed breeds! Further comment suggests it is possible that conformation of thorax and lung lobe attachments in Pugs may be faulty.
Online, Google revealed one comment stating: Breeds reported to have develop this condition include deep-chested dogs such as Afghans and Borzois, however other susceptible breeds include Miniature Poodles, Dachshunds, Shih Tzus, Yorkshire Terriers, Pekingese and Pugs. Several sites suggested the Afghan Hound was over-represented. All were based on international data and a few with long noses are mentioned.
Veterinary readers of the journal may now think Pugs are the predisposed breed and may well note the inference that brachycephalic dogs suffer lung lobe torsion. What do Pug owners think? I would be really interested to hear how many brachycephalic breeds have suffered a significant incidence of this condition in the UK. All reports I have read suggest it is rare in all breeds.
In the same journal another CPD article provides details concerning a bitch with thirst and incontinence. Both symptoms are associated with a long list of possible underlying causes and yet not once is there any mention that neutering might be a factor in incontinence. At its conclusion the report indicated this case proved impossible to resolve, perhaps there is a reason for this?
The third item is a report of a springer with immune mediated haemalytic anaemia (IMHA). A failure to detect an underlying cause leads the author to conclude a primary immune-mediated disease followed by an immediate reference to breeds predisposed to the disease (even though it’s accurately reported as a rare disorder). The breeds mentioned are Cockers, springers, Poodles, Old English Sheepdogs and collies.
These of course just happen to be some of the most popular breeds in the country but no mention is made whether or not their population size might be a factor. Google this time confirmed the list of breeds and added a whole lot more such as Irish Setter, Lhasa Apso, Dachshund, Malamute, Beagle and more.
In both cases no references were provided to support this view of breed disposition. The list became so long one might conclude IMHA might occur in any dog. The original dog in the reported case apparently made a good recovery.
Naming breeds in this negative fashion requires justification, especially for a rare condition. Reference to source data frequently demonstrates how breeds become incriminated by report rather than by good incidence data.
Many more examples of biased reporting could be provided from various regularly published science journals. The underlying point is the habit scientists have of quoting other published evidence without their own critical review. Quite simply, once somebody suggests a possible breed predisposition this becomes quoted and accepted as fact by everybody who publishes on the subject thereafter.
This colours the veterinary profession’s view of breed health. Furthermore, now published papers are increasingly being read and quoted by the layperson, the risk of misunderstanding and error is compounded. As an example, a recently launched website, from a well-intentioned layperson, details the health status of pedigree breeds in the UK.
It suggests to the unsuspecting public (who believe much they read on the web) that certain health tests are mandatory. However, being based on amateur research there are many errors on this site and as a result misinformation will be provided to the public.
This error is further compounded by endorsements from respected organisations who either did not have the resources to check the accuracy of the advice given or lacked the competence to judge it.
This all demonstrates why breeds must take control of health reporting to ensure accurate and reliable data and information reaches the public.
There is hope however. Occasionally a critical review is published examining the past information published on a subject. Most recently a review in the Journal of Small Animal Practice looked at ‘The effect of neutering on the risk of mammary tumours in dogs ….’ (JSAP Vol 53, June 2012).
The review summary states: ‘A commonly stated advantage of neutering bitches is a significant reduction in the risk of mammary tumours, however the evidence for this has not previously been assessed by systematic review.’
It concludes: ‘Due to the limited evidence available and the risk of bias in the published results, the evidence that neutering reduces the risk of mammary neoplasia, and the evidence that age at neutering has an effect, are judged weak and are not a sound basis for firm recommendations.’ In plain English, justifying early neutering as a means to prevent mammary cancer is not based on reliable information. Food for thought.