Relationship between body adiposity, metabolic status, and intraocular pressure in dogs

BACKGROUND: In humans, obese and overweight individuals have higher intraocular pressure (IOP) than normal weight individuals. HYPOTHESIS/OBJECTIVES: To evaluate the association between IOP, body condition indices, and obesity-related metabolic variables in dogs. ANIMALS: Forty staff-owned healthy dogs. METHODS: Prospective, observational study. Dogs underwent complete physical and ophthalmic examinations. Body condition score (BCS), body mass index (BMI), and body fat index (BFI) were recorded, IOP measured, and blood samples analyzed. Dogs were classified as lean-normal (BCS 2-5/9) or overweight-obese (BCS 6-9/9). Associations between IOP and body condition indices were assessed with Spearman's correlations and multiple linear regression, adjusting for BCS. RESULTS: Median (2.5th-97.5th percentile) IOP was significantly higher in overweight-obese dogs than in lean-normal dogs [20.3 (15.9-23.0) mmHg vs 13.7 (11.7-19.1) mmHg; P < .001]. Intraocular pressure correlated strongly with BCS (rs = 0.767), moderately with BMI (rs = 0.633), and weakly with BFI (rs = 0.401) (all P < .05). Intraocular pressure increased by 1.9 mmHg (95% CI, 1.38-2.50) for each 1-unit rise in BCS, by 2.9 mmHg (95% CI, 1.8-3.9) for each 10% increase in BMI, and by 1.8 mmHg (95% CI, 0.3-3.3) for each 10% increase in BFI. Serum triglycerides, leptin, and nonesterified fatty acids were higher in overweight-obese dogs and correlated positively with IOP, but these associations were not significant after adjusting for BCS. CONCLUSIONS AND CLINICAL IMPORTANCE: Higher body condition in normal dogs is significantly associated with higher IOP. Obesity might be a modifiable risk factor in dogs predisposed to glaucoma.