Every generation or two, people get frustrated with diabetes nomenclature, and after much pushing and shoving, the names of the different varieties of diabetes get changed.
Years ago, diabetes was not subdivided. But it was noted that sometimes folks who got diabetes as adults lived longer, and that kids developing diabetes tended to die rapidly, so it seemed logical that diabetes could be subdivided into childhood-onset diabetes and adult-onset diabetes. But as it was also noted that there were lots of adults with diabetes where the disease looked like childhood-onset (that is, these adults were skinny and needed insulin supplementation) and lots of kids with diabetes that looked like they had adult-onset version (that is, these kids were obese and could be treated without insulin supplementation), it became more and more difficult to rationalize that the age of onset should be the determining factor in deciding if someone had this type of diabetes or that type.
The alternative that was proposed was to classify people by whether or not they needed insulin supplementation: those that did were called by the ungainly term "insulin-dependent diabetes mellitus" (IDDM) and those that didn't, were called by the even uglier term "non-insulin-dependent diabetes mellitus" (NIDDM).
That terminology didn't last long before it was replaced by "Type I" and "Type II" diabetes - later adjusted to remove the capitalization and change the Roman numerals to Arabic, thus becoming type 1 and type 2 diabetes. These are the presently-used terms.
Of course, you are well aware that there are lots of other types of diabetes that don't fit at all into the this-vs-that categorization described above: there's diabetes with onset during pregnancy (called gestational diabetes), diabetes secondary to other disorders such as cystic fibrosis, hemochromatosis, hyperthyroidism, et. al, and other genetic forms of diabetes such as MODY diabetes and neonatal diabetes, and my personal favorite for confusing everyone: LADA diabetes (Latent Autoimmune Diabetes in Adults).
The presently-used terminology is partially based on whether the patient's diabetes is autoimmune (in which case it usually but not always is type 1) or not (in which case it's probably, but not necessarily in the type 2 group). But among many other failings of the present terminology is the simple fact that "the first type" - type 1 - is much less common that the one that got annointed with the second type - type 2 diabetes.
There's an on-line petition at Change.org to encourage the leaders of the American Diabetes Association, the National Institutes of Health, and the International Diabetes Federation to convene a workgroup to revise the terminology to more accurately describe the various types of diabetes. The petition is not proposing new names to be adopted, but rather, is requesting that the experts come up with a better way to differentiate the various versions of diabetes. As the petition says "A name change is not a monumental task. It has been done before. The time has come to do it again."
I agree; I've signed the petition. I urge you to review the petition, and ask that you also sign it.