Two hundred years ago, a myriad of diseases were known by a single term: fever. We still use the word as a part of some disease names today – yellow fever, scarlet fever – but more often today the word “fever” is used to describe a symptom: body temperature above the narrow range that is normal for a human being. We have inoculations and other measures to prevent or cure many of the diseases once grouped as “fever,” and if those diseases had not been separated, this could never have happened.
Diabetes melltus, as defined today, is an elevation of blood sugar – more accurately, of blood glucose. Like body temperature, the human body needs a particular amount of sugar in the blood. Too much, and there are all kinds of long-term consequences to blood vessels and all that depend on them – kidneys, wound healing, eyes, the nervous system …. Too little and the brain, which more than any other organ requires glucose as a fuel, shuts down. (I’ve used this as a basis for esper shock in Homecoming and Tourist Trap.)
The body of a healthy person has a number of feedback mechanisms to keep both body temperature and blood glucose within the ranges necessary for life. Blood glucose feeds the cells of the body, but the use of blood glucose by the cells requires a hormone, insulin. If the blood glucose goes too high, the islets of Langerhans in the pancreas pump out more insulin. This allows the cells either to use the glucose for themselves, to store it short-term in muscles and liver, or to store it long-term as fat. If the blood glucose goes too low, glucose is released from the liver or used as fuel by the muscles which have stored it.
When these mechanisms go awry, the result is diabetes. But there are many ways they can go awry. You can treat a fever with aspirin, cold cloths, or ice, but to prevent or cure the fever, you need to know what is causing it. And there are many ways the regulation of blood sugar can go awry.
When I was first diagnosed with diabetes, 42 years ago, there were assumed to be two types of diabetes: juvenile and adult. On age, I fell in the crack. Juvenile diabetes required insulin, which must be injected into the body, and one simply does not get over this type of diabetes. Adult diabetes could often be treated with oral medications or even with diet. Since I did not respond to medication, I was assumed to have juvenile diabetes.
Today we have type 1 (defined as autoimmune destruction of the ability to produce insulin) type 2 (often considered due to overweight and lack of exercise, but there is evidence that fairly thin people can present with type 2) LADA, gestational diabetes (which may disappear immediately after the baby is born but may go on to develop into type 1 or type 2) and even a type that looks like type 1 but clears itself up. Not to mention the fact that the islets of Langerhans can be destroyed or damaged by things other than autoimmunity, such as chemicals or actual removal of or injury to the pancreas.
Why can’t we accept that diabetes is not in itself a disease, any more than fever is, but a symptom of a large number of diseases?
It is true that there are two major intermediate causes of diabetes, which may occur together or separately.
The more common cause, often associated with a modern sedentary lifestyle, is insulin resistance. There is plenty of insulin available, but the cells seem unable to use it to metabolize sugar. In fact, the body may overproduce insulin in an effort to make up for the insulin resistance, ultimately leading to the death of the insulin-producing cells and the need for insulin therapy. But this is an intermediate cause. The chances are that there are several underlying disease states that produce insulin resistance, some of which may be hereditary, dietary, lifestyle or chemicals. But we’re not likely to find them unless we quit lumping all insulin resistance as type 2 diabetes.
The rarer intermediate cause is an inability to produce insulin. If this inability is due to an autoimmune attack on the islets of Langerhans, the result is type 1 diabetes. That of course leaves the cases of insulin-dependent diabetes due to actual injury or destruction of the pancreas by other than autoimmunity, or the inability of the islets to produce insulin for reasons other than their destruction, out of the definition, though as far as treatment goes, they are type 1. Even the autoimmune destruction may have many triggers. Things as far apart as viruses and cows’ milk have been suggested.
Treatment is insulin – first obtained from beef and/or pork pancreases, but now biologically (bacterially) produced using the chemical structure of human insulin. Some insulins further modify this structure to give faster or slower action. Because insulin is a protein which would be destroyed by the digestive system, it must be given under the skin using a hypodermic, an insulin pen or an insulin pump. Without insulin, death can occur within days.
I’ll probably visit this subject again – it’s a favorite rant of mine. Meanwhile, the symptom of diabetes is increasing in frequency worldwide. Why? And which underlying diseases are actually increasing?