Some readers will remember me writing about the Dachshund Breed Council’s 2015 Breed Survey: DachsLife 2015. The aim of the survey was very specific – to identify any lifestyle factors that contributed to the risk of back disease (IVDD). The original survey design was done in conjunction with Rowena Packer and her colleagues at the Royal Veterinary College (RVC). We deliberately involved them in the design because we had ambitions to gather lots of data that could be used to build on Rowena’s earlier work on the conformational risk factors associated with IVDD. In 2013, Rowena published her paper “How long and low can you go?” which showed that the longer a Dachshund’s body, the higher was its risk of IVDD. This clearly had implications for breeders and judges, but we also wanted to explore what owners could do.
After we had reported our results, we handed the data over to Rowena to work her magic with the more sophisticated statistical analysis tools she has available. Now, we have just published that further level of analysis in the peer-reviewed journal of Canine Genetics and Epidemiology.
One of the great things about this journal, which is sponsored by the Kennel Club, is that all the articles are Open Access. I strongly believe that sharing data and making the results of scientific studies widely available is key to making progress with any sort of improvement. So, not only can readers read the full text of our paper, but they can also access the anonymised source data. Anyone can repeat our analysis and interrogate the data further.
“Without data, you’re just another person with an opinion” (Dr. Deming)
As soon as data, research and analysis are put into the public domain, people can begin to make informed decisions.
Of course, the data and analysis may well challenge existing preconceptions and urban myths. Our Dachshund analysis was no different. Conventional wisdom would have you believe that allowing your Dachshund to jump on/off furniture, or to run up and down stairs is potentially bad for their backs. The analysis actually showed the reverse; those dogs who were allowed to do those things had a lower odds of having IVDD.
We do have to be careful to remember that correlation does not imply causation and we point out in the paper that there may be a danger of “reverse causation” with some of the results. For example, it may be that dogs whose backs have herniated were subsequently not allowed to jump on/off furniture or go up/down stairs. The missing data is “when” did those activities start/stop in relation to the herniation. We can, however, find other studies which also showed that this sort of activity reduced the risk of IVDD. The practical advice for owners arising from the activity/exercise findings is that keeping your Dachshund fit and active is one way to reduce the risks of IVDD. It’s common sense and any reasonable person would expect a fit, well-muscled dog to be able to lead a normal lifestyle coping with furniture and stairs.
Another surprise from our analysis was that neutered/spayed Dachshunds had an increased odds of IVDD compared with entire dogs. In this case, we can be more confident that it is not a case of reverse causation (e.g. dogs with IVDD were subsequently neutered) because we know the age of neutering and the age of IVDD diagnosis. Indeed, we found that the younger a dog was neutered, the higher its odds of IVDD. This finding should not surprise us in light of numerous other studies in dogs (and people) that challenge the claimed health benefits of neutering.
This finding is going to be a hard one to sell to many vets who still seem keen to encourage new puppy owners to book their dog in to be spayed/neutered as soon as possible after its vaccinations or before 6 months of age. However, in this emerging age of evidence-based veterinary medicine, vets will, I suspect, find some of their prejudices and biases challenged.
Big data gives you big insights
One of the interesting challenges when the paper was peer-reviewed was around biases in the data. The survey participants were self-selecting, they were willing to “own up” to health issues in their dogs, they may have been keen to “make a point”. They all responded via the internet in an online survey, so there may have been demographic biases in the respondent population.
Our argument was that, if you have large volumes of data, these sorts of bias are less significant. We had over 2000 responses and looked at more than 50 variables in the lifestyle factors. The VetCompass project is similar; with literally millions of case reports from first opinion veterinary practices, the volume of data permits deep insights to be obtained with high statistical confidence.
Of course, we have to remember that epidemiological studies draw conclusions about populations, not individual dogs. Inevitably, there will be owners whose personal experience differs from the findings at population level. In our case, there will be comments like “my dog jumped off the chair and ended up paralysed” or “my dog was fit and well-muscled, but still had IVDD”.
Those individual cases are entirely to be expected and do not diminish the advice we are able to give owners based on population-level insights. We know that, fundamentally, IVDD has a strong genetic component and is highly heritable. Nevertheless, if every owner adopted the good lifestyle choices we have been able to identify, I am convinced that it would make some inroads into the risks of IVDD. I’ve written previously about Dave Brailsford’s 1% Principle: lots of small changes can aggregate to make a significant difference.
While I have focused on Dachshunds and IVDD in this article, I am sure the principles apply more widely:
- Breed Health Coordinators and their committees should think about the design of their health surveys with a view to carrying out deeper analyses
- There are many situations where breeds already have lots of data; collecting more or different data is not the solution; we often just need more insight from analysis of existing data
- The answers lie in the data, but don’t be surprised if some people (owners, vets, breeders) feel challenged or exposed by this, particularly when the results run counter to their perceived wisdom (see my article on Cognitive Dissonance)
Finally, remember “Prejudice is a great time-saver; it enables you to form opinions without having to gather the facts”.