The pancreas is responsible for two major functions in a cat’s body. While one of its functions is to produce enzymes that regulate digestion, the other is to produce insulin that regulates the level of glucose in the blood. Insulin is a hormone produced by a group of cells known as beta cells. When there is deficient or less production of insulin, it results in diabetes. This condition can be diagnosed and treated successfully. It is said that Burmese cats in Australia and the United States are four times more likely to develop diabetes.

Currently, the classification of causes in veterinary medicine is based on human diabetes.

1. Types of diabetes
The various types of diabetes are Type 1, Type 2, gestational, and other specific types. Type 1 diabetes is characterized by immune-mediated destruction of cells, which leads to absolute immune deficiency and it is extremely rare in cats. Around 90% of diabetes mellitus cases in cats are Type 2 diabetes. Such cases are characterized by insulin resistance and failure of the body to compensate for it. Although Type 2 diabetes is more common, other causes too could contribute to insulin resistance. Gestational diabetes has not been reported in cats so far.

2. Causes of diabetes
Key factors that contribute to diabetes mellitus in cats are increased age, male gender, obesity, indoor confinement, physical inactivity, breed, and repeated or long-acting steroid administration. These factors lead to lower insulin sensitivity and increase the demand to produce more cells. Compared to normal cats, cats with diabetes are approximately six times less sensitive to insulin. The factors associated with Type 2 diabetes impair the ability to secrete insulin. It also affects the capacity to produce extra insulin leading to uncontrolled cell death.

In cats, the development of diabetes mellitus could also be caused by the loss of pancreatic islets from pancreatitis. Pancreatitis may be present in up to 60% of diabetic cats. In most cases, pancreatitis not only cause diabetes but also contributes to a beta-cell loss. This could influence the probability of diabetic remission. In simple terms, diabetes mellitus in cats is caused by the failure of the pancreas to regulate blood sugar. Diseases like hyperthyroidism as well as medication like corticosteroids may also make cats more prone to develop diabetes mellitus.

Obesity is said to be a predisposing factor in Type 2 diabetes and is said to be the most common type of diabetes mellitus in cats. Though the exact incidence is unknown, the number of diabetic cats in the country is increasing at an alarming rate due to the tremendous increase in the number of overweight and obese cats. It is to be noted that if a cat weighs 3 pounds more than its ideal weight it is considered obese and is at high risk for developing Type 2 diabetes.

Endocrine diseases such as acromegaly are other factors that contribute to insulin resistance. It affects 20%–30% of diabetic cats and is usually diagnosed by measuring the concentration of insulin-like growth factors in the blood. Cats that have been neutered have nearly twice the risk of developing diabetes mellitus, and male cats 1.5 times the risk.