Cambridge study widens BOAS risk list across brachycephalic breeds: full analysis

A new University of Cambridge study is widening the clinical picture of brachycephalic obstructive airway syndrome in dogs. Published February 18, 2026, in PLOS One, the cross-sectional study found that 12 of 14 brachycephalic breeds evaluated showed detectable breathing abnormalities, with Pekingese and Japanese Chin emerging as the highest-risk breeds in the cohort. (journals.plos.org)

That matters because prior BOAS research and public attention have largely centered on French Bulldogs, Pugs, and Bulldogs. Cambridge said this new work was designed to move beyond those three heavily studied breeds by adapting the established Respiratory Function Grading Scheme for 14 additional breeds and applying it in referral-hospital appointments, dog shows, and breed health-testing events. The broader message is that BOAS risk varies not only between breeds, but within breeds, and isn't captured well by a one-size-fits-all view of "flat-faced dogs." (vet.cam.ac.uk)

The study enrolled 898 dogs across Affenpinscher, Boston Terrier, Boxer, Cavalier King Charles Spaniel, Chihuahua, Dogue de Bordeaux, Griffon Bruxellois, Japanese Chin, King Charles Spaniel, Maltese, Pekingese, Pomeranian, Shih Tzu, and Staffordshire Bull Terrier. According to the paper, only Maltese and Pomeranians had no dogs with clinically significant BOAS in this sample. Pekingese and Japanese Chin had the lowest proportion of unaffected dogs, and the authors categorized five breeds, including Shih Tzu, as moderate risk. Staffordshire Bull Terriers were placed in a mild-risk group, meaning clinically important disease was less common, but not absent. (journals.plos.org)

The paper also sharpened the discussion around modifiable and structural risk factors. Across the full study population, higher body condition score, nostril stenosis, and more extreme facial shortening were significantly associated with BOAS. Age was also positively associated with BOAS status in the study population, while sex and neuter status were not significantly correlated. For practicing veterinarians, that adds weight to routine body-condition counseling and careful upper-airway assessment in brachycephalic patients that might not traditionally trigger BOAS concern. (journals.plos.org)

Cambridge researchers framed the findings as a step toward more precise, breed-specific prevention strategies. In the university announcement, they said BOAS exists on a spectrum, from mild noisy breathing to severe disease that can impair exercise, sleep, and tolerance of heat or stress. They also noted that while surgery and weight management can help some affected dogs, the disorder is hereditary, underscoring the limits of case-by-case treatment without parallel breeding reform. (vet.cam.ac.uk)

Outside commentary from Cornell’s Riney Canine Health Center aligns with that clinical concern. Cornell describes BOAS as a condition tied to upper-airway abnormalities such as stenotic nares, elongated soft palate, everted laryngeal saccules, and, in some dogs, hypoplastic trachea. The center notes that more severe cases may require surgical correction and that these patients also carry anesthetic risk, points that are especially relevant for general practitioners managing routine procedures in brachycephalic dogs. (vet.cornell.edu)

Why it matters: For veterinary teams, the practical takeaway is that BOAS case-finding may need to become broader and earlier. A dog doesn't have to be a French Bulldog, Pug, or Bulldog to warrant questions about noisy breathing, exercise intolerance, sleep disruption, thermoregulation, or peri-anesthetic planning. The study also supports using objective grading and phenotype-based counseling with pet parents, especially around weight control and the clinical significance of narrowed nostrils and extreme craniofacial conformation. At a population level, the findings may also influence breeding advice, referral thresholds, and how clinics educate pet parents who may normalize chronic respiratory noise as breed-typical. (journals.plos.org)

What to watch: The next development to watch is whether existing BOAS screening frameworks, including the Royal Kennel Club-University of Cambridge Respiratory Function Grading scheme, are formally expanded to cover more breeds, and whether breed clubs and welfare groups use these data to push for revised breeding practices and conformation standards. (royalkennelclub.com)