Breathing Problems Aren’t Just a French Bulldog Issue, New Study Finds

It’s no secret that French Bulldogs, Bulldogs, and Pugs face a myriad of health problems, specifically when it comes to breathing. But while they might be the most commonly studied flat-faced dogs with breathing problems, new research shows that other dog breeds can be just as affected.

The structure of these breeds’ heads, with their flat faces and short muzzles, might be adorable, but it can cause many of them to have respiratory trouble. Veterinarians refer to this condition as Brachycephalic Obstructive Airway Syndrome (also known as BOAS). BOAS leads to noisy breathing, reduced exercise tolerance, and other health complications. 

A new study published in PLOS One analyzed the frequency of BOAS across less-studied breeds. And the researchers found that other flat-faced breeds can suffer from BOAS just as much as French Bulldogs, Pugs, and Bulldogs.

The UK-based researchers examined 898 dogs across 14 different breeds, which included Malteses, Pomeranians, Japanese Chins, Pekingese, Griffon Bruxellois, Boston Terriers, Affenpinschers, Boxers, Chihuahuas, Dogue de Bordeaux, Cavalier King Charles Spaniels, King Scharles Spaniels, Shih Tzus, and Staffordshire Bull Terriers. All the dogs were over a year old and studied from the period of September 2021 to April 2024.

The dogs were examined at the Queen’s Veterinary School hospital, at dog shows, and at breed health-testing days. Each dog was administrated a standardized breathing check, which also included three minutes of exercise. The researchers listened to the dogs’ breathing before and after the run, then graded the noisy breathing and signs of respiratory distress on a scale of 0 to 3. Anything above a 2 counted as significant.

The researchers identified that two breeds — the Pekingese and the Japanese Chin — have comparable rates of BOAS to the Pug, French Bulldog, and Bulldog. Around 90 percent of Pekingese dogs and 83 percent of Japanese Chins have some degree of BOAS. 

Additionally, five other breeds — the Griffon Bruxellois, Boston Terrier, King Charles Spaniel, Dogue de Bordeaux, and Shih Tzu — were at significant risk of BOAS, with 50 percent of the sample size exhibiting some degree of symptoms. Meanwhile, the Staffordshire Bull Terrier, Cavalier King Charles Spaniel, Chihuahua, Boxer, and Affenpinscher were found to have a mild risk of BOAS. As for the Pomeranian and Maltese dogs, no signs of significant BOAS were found in their sample populations. The study notes, however, that they had less Pomeranian and Maltese dogs than the other breeds. 

While flat-faced breeds are definitely at risk of developing BOAS, the study found that some of them, had lower rates of BOAS than the researchers hypothesized. The head structure is only part of the story. The researchers were able to identify some other factors that differed across breeds. For instance, Shih Tzus and Staffordshire Bull Terriers with shorter tails were more likely to exhibited BOAS, while Boston Terriers and Staffordshire Bull Terriers with thicker necks faced a higher risk. 

“Their findings fit with what we see clinically in these pets — that, while generally the flatter-faced a particular breed or individual within a breed is, the more likely they are to suffer from BOAS, there are breeds that behave as outliers, having either unique problems not seen in other brachycephalic breeds, or suffering less from problems most of the other breeds suffer,” Heidi Phillips, a veterinary clinician and surgeon at the University of Illinois who is not affiliated with the study, said to Gizmodo.

Overall, the researchers determined that extreme flat faces, narrow noses, and high body fat are associated with increased BOAS risk. But the nuances of risk vary from breed to breed. The study shed some light on the prevalence of BOAS among less-studied breeds, which will hopefully pave the way for more research. While treatment of BOAS is possible through weigh management and surgery, the scientists say that the best cure is prevention through more careful and ethical breeding and awareness of risk. 

“BOAS exists on a spectrum,” said Dr. Fran Tomlinson to ZME Science. “For those at the more severe end, it can significantly reduce quality of life and become a serious welfare issue.”