Just what is diabetes, what causes it, and why is it an issue?

The mass media love to play up the sensationalized "diabetes epidemic", ignoring that there is more than one form of diabetes, only one of which is soaring, and often failing to mention that issues relevant to one form may not apply to others.

The medical community, on the other hand, recognizes three major (and several minor) variations on diabetes based on how exactly it came about, yet research and recommendations are all too often done on the basis of "diabetes" as if it were a unified whole without regard for those variations.

Singular Diabetes

Broadly speaking, diabetes - or, more properly, diabetes mellitus - is any condition which creates a tendency towards elevated blood glucose levels. This definition is purely symptomatic because it is rather old, predating our understanding of the underlying mechanics by many centuries.

It is also a primary cause of the issues with failure to distinguish between different causes, as the symptoms have been elevated to the status of "disease".

There are two broad categories of diabetic causes, which must be recognized as distinct if we are to move beyond simply treating the shared symptoms:

Hypoinsulinism

The first, but less common, cause of diabetes is hypoinsulinism, or insufficient insulin production by the pancreas. In type 1 diabetes, hypoinsulinism results from an autoimmune response in which the insulin-producing pancreatic beta cells are attacked and destroyed by the immune system. It also appears in "secondary diabetes", a catch-all term for cases in which some other disease or injury resulted in loss of ability to produce insulin.

Hypoinsulinism is characterized by low or absent levels of naturally-occurring insulin in the blood. Without the presence of insulin, muscles are unable to metabolize glucose for energy and must resort to an alternate process, ketosis, to function. When ketosis becomes the primary energy source, acids called "ketones" build up in the blood, resulting in ketoacidosis, a life-threatening condition. Because of this, those of us with fully-developed hypoinsulinism (i.e., a loss of all insulin production) require injected insulin to survive on a day-to-day basis.

Depending on whose statistics you read, hypoinsulinism accounts for between five and ten percent of cases of diabetes.

Insulin Resistance

While hypoinsulinism results in elevated glucose levels due to lack of insulin, people suffering from insulin resistance often have extremely high levels of insulin in their blood, as their muscles fail to respond appropriately to the insulin. Insulin resistance is responsible for type 2 diabetes (a lifelong condition) and gestational diabetes (which generally resolves itself after pregnancy, but is also associated with increased future risk of developing type 2 diabetes).

In the case of type 2 diabetes, insulin resistance is also associated with a variety of other metabolic issues and cardiac risk factors, which are sometimes lumped together as "metabolic syndrome" or "syndrome X".

The most common treatments for insulin resistance focus on diet, exercise, and oral medications to increase insulin sensitivity. Weight loss can also help significantly. Other oral medications cause the pancreas to increase its insulin production, but are used less frequently due to concerns that they may lead to long-term loss of insulin-producing ability. As the condition progresses, it is often necessary to supplement these treatments with injected insulin, but this is rarely needed when initially diagnosed.

Other Names

Aside from the currently-used type 1/type 2 designations and my preferred usage of hypoinsulinism/insulin resistance, there are a couple other sets of names which have been widely used in the past:

• Insulin-dependent and non-insulin-dependent diabetes

This seems to have fallen out of use due to the uncertainty produced by people using injected insulin to supplement their natural production rather than as a replacement for its absence. If you need insulin to control your blood sugar, but can live without it, are you "insulin-dependent" or not? (I, like most people I've encountered who have type 1 diabetes, would say, "No, you're not," but there are a lot of people who use "insulin-dependent" to mean "insulin-using".)

• Juvenile and adult-onset diabetes

Traditionally, diabetes in children has been associated with type 1 and in adults (especially middle-aged or older adults) with type 2. Today, however, our ability to distinguish hypoinsulinism from insulin resistance has shown that over half of new diagnoses of type 1 diabetes are in adults and some research even suggests that there is no meaningful correlation to age. Conversely, increased rates of childhood obesity are resulting in type 2 diabetes appearing in children as young as seven years old.