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Multiple morbidities in companion dogs: a novel model for investigating age-related disease

View Article: PubMed Central - PubMed

ABSTRACT

The proportion of men and women surviving over 65 years has been steadily increasing over the last century. In their later years, many of these individuals are afflicted with multiple chronic conditions, placing increasing pressure on healthcare systems. The accumulation of multiple health problems with advanced age is well documented, yet the causes are poorly understood. Animal models have long been employed in attempts to elucidate these complex mechanisms with limited success. Recently, the domestic dog has been proposed as a promising model of human aging for several reasons. Mean lifespan shows twofold variation across dog breeds. In addition, dogs closely share the environments of their owners, and substantial veterinary resources are dedicated to comprehensive diagnosis of conditions in dogs. However, while dogs are therefore useful for studying multimorbidity, little is known about how aging influences the accumulation of multiple concurrent disease conditions across dog breeds. The current study examines how age, body weight, and breed contribute to variation in multimorbidity in over 2,000 companion dogs visiting private veterinary clinics in England. In common with humans, we find that the number of diagnoses increases significantly with age in dogs. However, we find no significant weight or breed effects on morbidity number. This surprising result reveals that while breeds may vary in their average longevity and causes of death, their age-related trajectories of morbidities differ little, suggesting that age of onset of disease may be the source of variation in lifespan across breeds. Future studies with increased sample sizes and longitudinal monitoring may help us discern more breed-specific patterns in morbidity. Overall, the large increase in multimorbidity seen with age in dogs mirrors that seen in humans and lends even more credence to the value of companion dogs as models for human morbidity and mortality.

No MeSH data available.


Morbidity scores and ages of dogs in the VetCompass data set. Shown are distributions of (a) morbidity scores and (b) age of dog at veterinary visit across all dogs in the data sets; (c–e) morbidity score and (f–h) age distributions of dogs are also visualized by body weight class as labeled. Total number of animals in each weight class is as follows: nsmall=766, nmedium=692, nlarge=1,128, and ntotal=2,586.
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Figure 0001: Morbidity scores and ages of dogs in the VetCompass data set. Shown are distributions of (a) morbidity scores and (b) age of dog at veterinary visit across all dogs in the data sets; (c–e) morbidity score and (f–h) age distributions of dogs are also visualized by body weight class as labeled. Total number of animals in each weight class is as follows: nsmall=766, nmedium=692, nlarge=1,128, and ntotal=2,586.

Mentions: The original database consisted of 3,225 adult dogs (aged over 1 year at their final record), of which 2,586 (80.2%) had both body weight and age data, and were thus included in the analysis. The distribution of morbidity scores across all dogs in the data set more closely follow a negative-binomial distribution rather than a Poisson distribution (AICnegbinom<AICpois; Fig. 1a). Morbidity scores across dogs separated by weight class follow very similar distributions (Fig. 1c–e; Mann–Whitney test results: p>0.05 for all pairwise comparisons), suggesting that there are very few differences between differently sized dogs in terms of the number of morbidities accumulated over the lifetime.


Multiple morbidities in companion dogs: a novel model for investigating age-related disease
Morbidity scores and ages of dogs in the VetCompass data set. Shown are distributions of (a) morbidity scores and (b) age of dog at veterinary visit across all dogs in the data sets; (c–e) morbidity score and (f–h) age distributions of dogs are also visualized by body weight class as labeled. Total number of animals in each weight class is as follows: nsmall=766, nmedium=692, nlarge=1,128, and ntotal=2,586.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5120387&req=5

Figure 0001: Morbidity scores and ages of dogs in the VetCompass data set. Shown are distributions of (a) morbidity scores and (b) age of dog at veterinary visit across all dogs in the data sets; (c–e) morbidity score and (f–h) age distributions of dogs are also visualized by body weight class as labeled. Total number of animals in each weight class is as follows: nsmall=766, nmedium=692, nlarge=1,128, and ntotal=2,586.
Mentions: The original database consisted of 3,225 adult dogs (aged over 1 year at their final record), of which 2,586 (80.2%) had both body weight and age data, and were thus included in the analysis. The distribution of morbidity scores across all dogs in the data set more closely follow a negative-binomial distribution rather than a Poisson distribution (AICnegbinom<AICpois; Fig. 1a). Morbidity scores across dogs separated by weight class follow very similar distributions (Fig. 1c–e; Mann–Whitney test results: p>0.05 for all pairwise comparisons), suggesting that there are very few differences between differently sized dogs in terms of the number of morbidities accumulated over the lifetime.

View Article: PubMed Central - PubMed

ABSTRACT

The proportion of men and women surviving over 65 years has been steadily increasing over the last century. In their later years, many of these individuals are afflicted with multiple chronic conditions, placing increasing pressure on healthcare systems. The accumulation of multiple health problems with advanced age is well documented, yet the causes are poorly understood. Animal models have long been employed in attempts to elucidate these complex mechanisms with limited success. Recently, the domestic dog has been proposed as a promising model of human aging for several reasons. Mean lifespan shows twofold variation across dog breeds. In addition, dogs closely share the environments of their owners, and substantial veterinary resources are dedicated to comprehensive diagnosis of conditions in dogs. However, while dogs are therefore useful for studying multimorbidity, little is known about how aging influences the accumulation of multiple concurrent disease conditions across dog breeds. The current study examines how age, body weight, and breed contribute to variation in multimorbidity in over 2,000 companion dogs visiting private veterinary clinics in England. In common with humans, we find that the number of diagnoses increases significantly with age in dogs. However, we find no significant weight or breed effects on morbidity number. This surprising result reveals that while breeds may vary in their average longevity and causes of death, their age-related trajectories of morbidities differ little, suggesting that age of onset of disease may be the source of variation in lifespan across breeds. Future studies with increased sample sizes and longitudinal monitoring may help us discern more breed-specific patterns in morbidity. Overall, the large increase in multimorbidity seen with age in dogs mirrors that seen in humans and lends even more credence to the value of companion dogs as models for human morbidity and mortality.

No MeSH data available.