Causes

We don't know exactly what causes diabetes in cats and dogs, but there's some excellent research being done on the question now.

In cats

Dr. Elizabeth Hodgkins, Dr. Jacquie Rand, Dr. Lisa Pierson, and some other vets believe that a typical dry commercial cat food diet is likely to cause diabetes in many cats, since cats are obligate carnivores (they must eat mainly meat), and it's species-inappropriate to have over 10% calories from carbohydrates in an obligate carnivore's diet.

See also this wiki's article on low-carbohydrate diets for a better feeding plan for your diabetic cat.

Dr. Rand also argues for genetic predisposition, (noting that more Burmese seem to become diabetic) and lack of exercise, as important factors. She also notes that 80-95% of all diabetic cats are type-II, meaning their pancreas is not damaged by the immune system, but by hyperglycemia and its complications.

Other known causes:

• Damage to the pancreas from amyloidosis, pancreatitis, Glucose toxicity, or hyperadrenocorticism.
• Steroids, often used as anti-inflammatories for other problems, are known to raise blood glucose and sometimes cause temporary diabetes.
• Animals may also develop secondary diabetes from a number of other conditions including insulin resistance and Cushing's disease.

Because of the vicious circles involved with hyperglycemia, (especially amyloidosis and glucose toxicity), this condition can sometimes become permanent. Cats with secondary diabetes, if caught early, can often go into remission. Dr. Rand's 2005 study goes even further, stating that early detection of feline diabetes can mean prevention--by changing or modifying diabetes-related factors such as weight reduction, diet changes, etc.

In dogs

Regarding causes in dogs, genetic predisposition has definitely identified keeshonds and samoyeds, with others who appear to be significantly susceptible. Middle aged to older dogs (5-12 years old--uncommon under the age of 3 years), and females versus males predominate.

As Dr. Rand noted, lifestyle is also a factor. Every informal poll taken at canine diabetes message board showed that most dogs were overweight at diagnosis.

Current research into canine diabetes finds no evidence of the Type 2 diabetes known in humans. Most dogs are what's termed Adult-onset IDD, meaning they are dependent on exogenous insulin for control of their diabetes, which did not occur until some point in their adulthood.

Pancreatic cells are either deficient due to congenital predisposition (breeds who are significantly susceptible), or lost/destroyed through pancreatitis or immune-mediated beta cell destruction.

Until recently, antibodies which interfere with a dog's receptivity to exogenous insulin therapy were considered rare. This research finds antibodies present in a significant segment of newly-diagnosed (insulin-naive) dogs. They conclude that canine diabetes is much like human adult latent autoimmune (Type-I) diabetes.

Further Reading

• Feline Diabetes Mellitus: Characteristics & Causes-Drs. Foster & Smith Pet Education Library
• Dr. Hodgkins' article on diet and diabetes
• Pancreatic Disease Cats
• Non-Pancreatic Origin Cats

• Primary & Secondary Canine Causes
• Familial Insulin-Dependent Diabetes Mellitus in Samoyed Dogs-JAAHA 2002
• Dog ear infection
• Pancreatitis in dogs
• Ivermectin for dogs
• How long are dogs pregnant
• Why do dogs eat grass
• Purina dog chow coupons

• Dr. Rand's article on causes of diabetes in cats and dogs