Cambridge study widens BOAS risk list to 12 more dog breeds: full analysis

University of Cambridge researchers say BOAS risk extends across a broader range of flat-faced dogs than many clinicians and pet parents may assume. In a PLOS One study published on February 18, 2026, the team reported that 12 additional brachycephalic breeds met criteria for being considered at risk of the serious respiratory disorder, with Pekingese and Japanese Chin showing the highest prevalence in the study population. Shih Tzu and Staffordshire Bull Terriers were also among the breeds flagged. (vet.cam.ac.uk)

The study builds on years of Cambridge work that helped define BOAS risk in Bulldogs, French Bulldogs, and Pugs, breeds that have historically dominated the literature and public discussion. According to Cambridge, this new project expanded the internationally recognized Respiratory Function Grading Scheme to 14 additional breeds and drew dogs from the Queen’s Veterinary School Hospital, dog shows, and breed health testing days between September 2021 and April 2024. (vet.cam.ac.uk)

In the paper, the researchers analyzed nearly 900 dogs and found that risk was shaped by more than breed label alone. Their multivariable model linked BOAS with overweight body condition, nostril narrowing, and lower craniofacial ratio, meaning a relatively shorter muzzle compared with skull length. The odds ratio for BOAS was 1.8 for dogs with body condition score 6 or higher, 4.2 for dogs with moderate nostril stenosis, and 10 for dogs with severe nostril stenosis, compared with dogs with open nostrils. The authors argue these findings support a more individualized, breed-specific strategy for reducing disease burden. (api.repository.cam.ac.uk)

That message aligns with broader professional concern about brachycephalic welfare. The British Veterinary Association says the rise in brachycephalic dogs has driven a population-level increase in ill health and compromised welfare, and it urges practices to use standardized exercise tolerance tests and functional grading, promote annual brachycephalic health assessments, and counsel pet parents that frequent snoring and snorting are not normal. Its guidance also emphasizes obesity as a factor that can worsen respiratory disease in these dogs. (bva.co.uk)

Cambridge’s clinical guidance helps explain why that matters in day-to-day practice. The university notes that BOAS can involve noisy breathing, sleep-disordered breathing, exercise intolerance, cyanosis, collapse, and impaired heat dissipation. Dogs graded as moderate or severe on functional assessment may need active management, including weight loss and, in some cases, surgical intervention. The workup can also include non-invasive whole-body barometric plethysmography and imaging to assess upper-airway and thoracic changes. (vet.cam.ac.uk)

Why it matters: For veterinarians, the takeaway is that BOAS case finding may need to widen. A dog that doesn't fit the public stereotype of a “classic” brachycephalic patient may still carry meaningful risk, particularly if it is overweight or has visible nostril stenosis. That affects preventive counseling, anesthetic planning, referral decisions, and breeding discussions. It also adds weight to the idea that conformation-focused health advice should be tailored by breed and phenotype, not delivered as a one-size-fits-all warning. (api.repository.cam.ac.uk)

The study may also sharpen conversations with pet parents around modifiable risk. Because body condition emerged as a significant factor, clinicians have a clearer evidence base for linking weight management to respiratory welfare in at-risk brachycephalic dogs. That fits with ongoing interest elsewhere in the field, including a Texas A&M clinical trial exploring whether weight loss can measurably improve breathing in overweight brachycephalic breeds. (api.repository.cam.ac.uk)

What to watch: The next step is likely translation into screening and breeding programs. Cambridge has already tied this work to expanded respiratory grading efforts, and the broader profession is pushing for evidence-based health assessments and healthier breed standards, so expect more pressure for earlier identification, breed-specific guidance, and practical interventions that can be used in first-opinion practice. (vet.cam.ac.uk)