Regional airway fat distribution and its association with brachycephalic obstructive airway syndrome severity in pugs with varying body condition.

Obesity is a recognised risk factor for brachycephalic obstructive airway syndrome (BOAS) in pugs; however, the mechanisms linking obesity to BOAS remain unclear. Previous veterinary studies have primarily focused on tongue fat, with limited evaluation of other airway regions. This study aimed to investigate the associations between body condition score (BCS) and regional airway fat, and their relationship with BOAS functional grades. Client-owned pugs undergoing BOAS assessment and pre-operative head and neck computed tomography (CT) were enrolled. Fat volumes within the tongue (T), pharynx (P), larynx (L), and total upper airway (V) were measured and normalised using a skull size index (S). Dogs were classified as non-obese (BCS = 4-5/9) or obese (BCS = 7-9/9), and BOAS severity was classified as grade II (moderate) or grade III (severe). Forty-nine BOAS-affected pugs (31 females and 18 males) were included, of which 17 were non-obese and 32 were obese. The median age was 45 months (range: 10-174 months). A significant positive association was identified between BCS and tongue fat (T/S) (p = 0.028). Moreover, pugs with grade III BOAS exhibited significantly greater laryngeal fat (L/S) than those with grade II BOAS (p = 0.034). These findings suggest that weight management and strategies aimed at reducing regional fat accumulation may help mitigate upper airway obstruction in obese pugs, particularly by targeting excess laryngeal fat, which was significantly associated with severe BOAS. Further research is warranted to investigate whether genetic factors influence regional airway fat distribution and to develop targeted treatment strategies aimed at reducing fat accumulation around the larynx.