It’s not unusual for research papers to get widely reported in the national press, particularly where it’s possible to spin a provocative headline that grabs readers’ attention. Lobby groups and campaigners are also skilled at selecting research that supports their cause. You’d be surprised if they didn’t do that; after all, they have a cause to promote.
In March 2019, I wrote about the discussions on social media when new scientific papers on canine health and welfare matters are reported and when breed clubs publish their health survey results. Newly published research should prompt us to ask the question “why?” – why might a particular association have been identified and why might the results have turned out like they did.
Last year, the VetCompass project published a paper that generated a lot of publicity in the national press. Life tables of annual life expectancy and mortality for companion dogs in the
United Kingdom reported an approach to assessing canine longevity (Life Tables) which is well-established in human health studies. The paper’s findings that the French Bulldog had the shortest life expectancy of just 4.5 years compared with Jack Russell Terriers (12.7 years) inevitably made for some eye-catching headlines. The VetCompass paper also reported the average longevity of Japanese French Bulldogs to be 10.2 years. Perhaps unsurprisingly, that figure didn’t feature in the press headlines.
In contrast, the Kennel Club’s 2004 and 2014 breed health surveys showed the median age of mortality of French Bulldogs to be 9 and 5.9 respectively. This data is summarised in the French Bulldog Breed Health and Conservation Plan. When the KC’s 2014 survey results were published in 2016, the overall median age of death of pedigree dogs was reported as 10, down from 11.3 in 2004. This led to descriptions of an “apocalyptic drop in purebred dog longevity” despite the fact that no such (statistically valid) conclusion could be drawn from the data reported.
Why the differences in longevity?
The VetCompass paper describes some of the limitations associated with the results they published. The limitations included:
- The sample size for FBs was relatively small, resulting in life tables with reserved confidence
- The sample was biased towards younger dogs that contribute proportionately more deaths in younger ages
VetCompass reports are based on a particular sample population – dogs attending first opinion vet practices in the UK. This sample will, like every sample, have its own biases. We know, for example, that insured dogs are more likely to be taken to the vet. The Life Tables paper was derived from a sample of nearly 900,000 dogs that had at least one visit to a vet
(90% in England) during 2016. These visits would have been not only due to illness but also included routine vaccinations. It is, therefore, not as simple as arguing that the dogs in the study were all ill. The paper drew data from nearly 900 vet clinics and VetCompass claims to gather data from about a third of all practices in the UK.
It is always worth looking at a range of research papers and analyses in order to build a picture of a breed’s health and longevity. Another useful source of such information is the International Partnership for Dogs (www.dogwellnet.com). They have collated and published data for many breeds, including French Bulldogs, Pugs and Bulldogs (all 3 of which have been the subject of recent VetCompass studies). Their Globally Relevant Integrated Health Profiles (GRIHP) are particularly useful as they pull together data from multiple sources, including UK and Swedish insurance data, VetCompass, Breed Club surveys and more. They don’t, however, provide any specific longevity statistics for French Bulldogs, only data on relative risk mortality compared with an all-breed average. The Agria data show, for example, that French Bulldogs have at least twice the relative risk of mortality than all breeds, for 6 types of health condition including respiratory, eyes and neurological.
One thing VetCompass does really well is communications; it publishes open-access peer-reviewed papers that meet the needs of a technical audience, with supporting data available. It also publishes infographics; easily digestible summaries that are visually appealing and comprehensible to the “person on the Clapham Omnibus”. VetCompass seems to practise a very “agile” approach to the use of its data assets. It publishes useful chunks of information at frequent intervals that answer specific questions.
Breed clubs need their own good quality research
If a breed has concerns about a particular health condition, age of death or cause of death, it should ensure it can collect sufficient good quality data from a representative sample of dogs. I have previously emphasised the value of clubs collecting data that can show any differences between sub-populations (e.g. show vs. working or show vs. non-show).
The point of Breed Health Surveys depends totally on “the exam question” you are setting out to answer. If the exam question is “what’s the biggest issue?”, most Breed Clubs’ surveys have been able to answer that. The KC’s 2004 and 2014 surveys did that too. If you want to know where to focus effort on improvement, asking about prevalence and age of diagnosis isn’t going to get you very far. You need to know about severity and welfare impact as well. Finally, if you want to know if there’s been any change (for the better or worse) over a period of time, you’d better make sure you’re measuring the same thing, in the same way, at the start and the end. Otherwise, you’ll end up with “Garbage in, Gospel out” with someone cherry-picking the results to suit their own argument!
VetCompass gives us “big data”; breed health surveys give us “small data”. We need both, but most importantly, we need to define the “exam questions” before rushing off to design surveys, or to see if we have data already available.
I believe that all our breed club communities should be supporting the development and use of The Kennel Club’s Breed Health and Conservation Plans (BHCP). These are the most comprehensive documents that summarise the breadth of research available. Breed club officers and health representatives need to be familiar with the content for their own breed so that they can present a balanced and evidence-based argument when challenged about health and/or longevity.
More data won’t improve dog health or longevity
In September 2020, I said that data are necessary but not sufficient. I went on to explain that without human behaviour change, the lives of dogs will not improve. The missing science is that of Human Behaviour Change.
We do need to question the research that is being published and to understand its strengths and limitations. Every piece of research has the potential to nudge us towards actions that will improve the health and longevity of our dogs. We need to see the bigger picture and focus on the behaviours of owners, breeders and vets who can all actually make a positive impact on dog health.