Obesity is widely recognized as the most prevalent nutritional disease in dogs, for which the reported incidence is 21.4% to 28.0%.1-3 Research studies4-6 have revealed a variety of deleterious effects of obesity in dogs, including increased incidence of orthopedic disease, shortened lifespan, and risk of death as a result of pancreatitis. Dogs of all breeds can become obese, but there is the clinical impression that some breeds are at higher risk, including Retriever breeds.
Obesity is also common in humans, and the incidence has risen dramatically over the past 20 years.7 Obesity increases the risk of death from all causes, is linked to increased risk of development of hypertension and type 2 diabetes mellitus,7 and negatively impacts cardiovascular8,9 and pulmonary functions.10-12 Specifically, obesity in people results in decreased FRC, increased Raw, decreased lung compliance, and hypoxemia at rest.13 Additionally, obstructive sleep apnea occurs more frequently with obesity because obesity is associated with increased pharyngeal fat deposits that cause airflow limitation during sleep.14
To our knowledge, the specific effects of obesity on the respiratory system in dogs have not been described, although it has been reported3.a that weight loss is associated with improved respiratory function in obese dogs. Further insight into the effects of obesity on pulmonary mechanics and gas exchange is needed and may provide an impetus for weight loss. The purpose of the study reported here was to evaluate the effects of obesity on pulmonary function in healthy adult dogs. Our hypothesis was that obesity in Retriever breeds causes mechanical dysfunction of the airways and, in particular, that obesity results in increased Raw during both inspiration and expiration in the absence of ventilatory limitations or hypoxemia.
Functional residual capacity
Body condition score
Specific airway resistance
Peak inspiratory flow
Peak expiratory flow
Diffusion capacity of lungs for carbon monoxide
Brinson JJ, McKiernan BC. Respiratory function in obese dogs with chronic respiratory disease and their response to treatment (abstr). J Vet Intern Med 1998;12:209.
TRD 5700, Buxco Electronics, Wilmington, NC.
Max 2270, Buxco Electronics, Wilmington, NC.
6023E, National Instruments, Austin, Tex.
XA Biosystem, version 2.9, Buxco Electronics, Wilmington, NC.
Fleisch No. 3, OEM, Lenoir, NC.
Max 2215, Buxco Electronics, Wilmington, NC.
Nova Biomedical, Waltham, Mass.
SPSS, version 11.5, SPSS Inc, Chicago, Ill.
Edney ATB, Smith PM. Study of obesity in dogs visiting veterinary practices in the United Kingdom. Vet Rec 1986;118:391–396.
Robertson ID. The association of exercise, diet and other factors with owner-perceived obesity in privately owned dogs from metropolitanPerth, WA. Prev Vet Med 2003;58:75–83.
Hess RS, Kass PH, Shofer FS, et al. Evaluation of risk factors for fatal acute pancreatitis in dogs. J Am Vet Med Assoc 1999;214:46–51.
Kealy RD, Lawler DF, Ballam JM, et al. Effects of diet restriction on life span and age-related changes in dogs. J Am Vet Med Assoc 2002;220:1315–1320.
Impellizeri JA, Tetrick MA, Muir P. Effect of weight reduction on clinical signs of lameness in dogs with hip osteoarthritis. J Am Vet Med Assoc 2000;216:1089–1091.
Caban AJ, Lee DJ, Fleming LE, et al. Obesity in US workers: the national health interview survey, 1986 to 2002. Am J Public Health 2005;95:1614–1622.
Hakala K, Stenius-Aarniala B, Sovijarvi A. Effects of weight loss on peak flow variability, airways obstruction, and lung volumes in obese patients with asthma. Chest 2000;118:1315–1321.
Biring MS, Lewis MI, Liu JT, et al. Pulmonary physiologic changes of morbid obesity. Am J Med Sci 1999;318:293–297.
Bedenice D, Rozanski E, Bach J, et al. Canine awake head-out plethysmography (HOP): characterization of external resistive loading and spontaneous laryngeal paralysis. Respir Physiol Neurobiol 2006;151:61–73.
Bedenice D, Bar-Yishay E, Ingenito EP, et al. Evaluation of headout constant volume body plethysmography for measurement of specific airway resistance in conscious, sedated sheep. Am J Vet Res 2004;65:1259–1264.
Agrawal KP. Specific airways conductance in guinea pigs: normal values and histamine induced fall. Respir Physiol 1981;43:23–30.
Amis TC, Jones HA. Measurement of functional residual capacity and pulmonary carbon monoxide uptake in conscious Greyhounds. Am J Vet Res 1984;45:1447–1450.
De Lorenzo A, Maiolo C, Mohamed EI, et al. Body composition analysis and changes in airways function in obese adults after hypocaloric diet. Chest 2001;119:1409–1415.
Rubinstein I, Zamel N, Duberry L, et al. Airflow limitation in morbidly obese, nonsmoking men. Ann Intern Med 1990;112:828–832.
Lutchen KR, Jensen A, Atileh H, et al. Airway constriction pattern is a central component of asthma severity: the role of deep inspirations. Am J Respir Crit Care Med 2001;164:207–215.
Trayhurn P. Endocrine and signaling role of adipose tissue: new perspective on fat. Acta Physiol Scand 2005;184:285–293.
Sagawa MM, Nakadoma F, Honjoh T, et al. Correlation between plasma leptin concentration and body fat content in dogs. Am J Vet Res 2002;63:7–10.
Jeusette IC, Lhoest ET, Istasse LP, et al. Influence of obesity on plasma lipid and lipoprotein concentrations in dogs. Am J Vet Res 2005;66:81–86.
Ishioka K, Omachi A, Sawawa M, et al. Canine adiponectin: cDNA structure, mRNA expression in adipose tissues and reduced plasma levels in obesity. Res Vet Sci 2006;80:127–132.