Feline diabetes - definition and contributing factors.
Diabetes in cats is on the increase. In the developed world, about one in every 400 cats suffers from the disease. As with their human partners, part of the increase in the illness is due to diet - obese cats and humans are particularly vulnerable. Here we describe what feline diabetes is and what factors can increase the risk of a cat getting it.
|Diabetes is caused by the inability of insulin (a hormone produced by the beta cells in the pancreas) to properly regulate blood sugar levels (glucose). Under normal conditions, glucose is produced following the breakdown of food by the body's metabolism (for example digesting carbohydrates will produce a lot of glucose). This glucose enters the blood stream, and once it reaches a certain level, this stimulates the pancreas to produce insulin. Insulin is essential in converting glucose into usable energy.|
This process keeps the glucose level in the blood low enough to avoid a condition known as hyperglycemia, and high enough to avoid the opposite condition (hypoglycemia). If the pancreas does not produce the right amount of insulin, a dangerous level of glucose will accumulate in the blood. At the same time, because glucose is not being produced, the body tries to compensate for the loss of energy by breaking down fat and muscle. Because the body disposes of some of the excess sugar in urine, the level of sugar in urine is a good indicator of diabetes or pre-diabetes in a cat (or human).
There are two types of diabetes: type I and type II. Type I diabetes affects approximately 5-20% of diabetic cats, whilst the remainer suffer from the type II form. Type 1 diabetes is the result of the destruction of the beta cells which produce the insulin. (The biological process which leads to the destruction of beta cells is complex and beyond the scope of this article). Type 2 diabetes is when the body no longer responds to insulin. In both cases the sugar level goes out of control and rises dramatically, leading to a short-term increase in body weight. However, in the later stages the body starts processing fat and proteins to get needed energy, and cats lose weight.
The risk of diabetes can be increased by the following factors:
1. Genetic predisposition
Burmese cats contract diabetes about three times more often than most other breeds (including domestic short-hairs -i.e. non pedigree cats). As many as 10% of older Burmese can contract diabetes, and studies in Australia, New Zealand and the UK have shown that genetic factors are major reason for this.
2. Environmental factors
Diabetic cats are often strictly indoor cats. This may be due to the lesser amount of physical activity and the consequent higher risk of obesity. Other factors which may contribute to diabetes among indoor and outdoor cats are chronic infections, including dental problems. A connection has also been found between diabetes and high doses of steroids. There is a higher risk of diabetes within the two years following corticosteroid treatment.
3. Insulin resistance
Insulin resistance means that it takes more insulin to process glucose. As a result, the bodies of cats with insulin resistance try to compensate by over-producing insulin. Sometimes this strategy is successful, but the high production of insulin puts a strain on the beta cells which produce it, and this often results in these cells being damaged or killed. In this case the cat will develop diabetes.
Insulin resistance can be caused by:
- obesity. This comes high on the list since insulin sensitivity is decreased by 50% in obese cats.
- some drugs, especially glucocorticoids. These are known to increase the risk of insulin resistance
- being male. It seems that male cats in general (even lean cats) have a higher insulin level and tend to be more insulin resistant. Males are also more likely to put on weight which increases the risk of diabetes
- diet. Cats are obligatory carnivores (eating meat is essential to their health). A mouse, which would be a staple food for a cat living wild, contains approximately 2% carbohydrates. This is about right for the feline metabolism. However some cat foods, especially cheaper varieties, may contain as much as 50% carbohydrates. Since glucose is produced by carbohydrate breakdown, more carbohydrates in the diet means more glucose in the blood. The cat's body winds up insulin production to cope, and the beta cells are put under strain.
4. Glucose toxicity
This really goes hand in hand with insulin resistance and diet. As the glucose level increases, this puts stress on the beta cells by forcing the overproduction of insulin. Studies have shown that even moderately high levels of glucose in the blood will exhaust a normal cat's insulin within 3 to 7 days. If the amount of glucose is brought down, the cat's system will recover, but if that level stays high for about 4 weeks there will be permanent damage to the beta cells, and the cat will develop diabetes.
Note: This information is for guidance only. It is not intended to replace consultation with a licensed practitioner.