Understanding the relationship between size, age, and disease prevalence allows for more informed healthcare decisions.
Canines, much like human beings, experience a spectrum of health challenges not only as they age but also as their weight varies. A recent study, conducted within the framework of the Dog Aging Project, explores the relationship between canine size, age, and the prevalence of various diseases.
The investigation, utilizing owner-reported data on disease history from a substantial number of companion dogs, sought to quantify how the pattern of disease history varies across the spectrum of dog size, age, and their interaction.
Size
Canine size is a key factor in disease risk. While smaller dogs tend to enjoy longer lifespans, this study reveals certain diseases show a higher prevalence among smaller breeds.
The results of the study are compelling, showcasing significant positive associations between dog size, measured by weight, and the lifetime prevalence of various conditions. Diseases affecting the skin, bones/orthopedics, gastrointestinal system, ear/nose/throat, cancer/tumor, brain/neurologic functions, endocrine system, and infectious diseases were more prevalent in larger dogs. Conversely, smaller dogs exhibited a higher lifetime prevalence of conditions related to ocular, cardiac, liver/pancreas, and respiratory health. Intriguingly, kidney/urinary disease prevalence did not vary significantly based on size.
Age and Size Interaction
Exploring the age factor, the study found that the association between age and lifetime disease prevalence varied by dog size for several conditions. Conditions such as ocular, cardiac, orthopedic, ear/nose/throat, and cancer demonstrated a size-dependent relationship with age (more information can be found here).
The study also controlled for factors like sex, purebred vs. mixed-breed status, and geographic region, and revealed that these factors made little difference in the studied disease categories.
The findings align with the common observation that larger dogs tend to have a reduced life span across most disease categories. The complexities revealed in the study prompt further exploration into the mechanisms behind these patterns and potential avenues for refining our understanding of canine health.