Friday, May 2, 2008

Type What?

A study published in the most recent edition of the journal Diabetes makes it even more clear that the usual division of diabetes into "Type 1" and "Type 2" is an oversimplification.

The usual mythology has it that Type 1 is an autoimmune disease and people who get it are innocent bystanders while Type 2 is caused by overindulgence and people who get it should be ashamed of themselves.

I've written at length about why the second part of this formula is bull crud. You can read the many reasons HERE.

But there is no question that framing the diagnosis of diabetes this way has made many people with autoimmune forms of diabetes hostile to those with Type 2, because they feel that an ignorant public unfairly blames them for causing their condition and believe, with the rest of that ignorant public that those gluttonous lazy type 2s do deserve such blame.

But the latest research on LADA, the adult onset form of autoimmune diabetes, has come up with a finding that makes it clear how wrong this kind of thinking is. The researchers in this study, which you can find at the Diabetes web site:

Autoimmune Diabetes in Adults, Type 1 Diabetes, and Type 2 Diabetes

examined the genes of 361 peole with LADA, 718 people with type 1 diabetes, and 1,676 type 2 diabetic patients, as well as 1,704 healthy control subjects from Sweden and Finland.

They found that "LADA subjects showed, compared with type 2 diabetic patients, increased frequency of risk for the HLA-DQB1 *0201/*0302 genotype with similar frequency as with type 1 diabetes (36%)." There were some other similarites with Type 1, genetically, but then they also found that "the frequency of the type 2 diabetes–associated CT/TT genotypes of rs7903146 in the TCF7L2 were increased in LADA subjects (52.8%; P = 0.03), to the same extent as in type 2 diabetic subjects (54.1%, P = 3 x 10–7), compared with control subjects (44.8%) and type 1 diabetic subjects (43.3%).

In short, these LADAs had both type 1 genes--autoimmune genes--AND type 2 genes.

This finding is particularly interesting in light of an earlier finding that slightly under 10% of people diagnosed with Type 2 also have autoimmune markers like elevated GAD antibodies.

TCF7L2 is one of the more common defective genes found in Type 2 diabetes but by no means the only one. HNF4-a is another gene that has been found in association with both a form of MODY and with a Type 2 diabetes in both Ashkenazi Jewish and Danish populations.

In addition, as they get older, many Type 1s find their insulin needs rise, as they become insulin resistant and probably start expressing the Type 2 genes they inherited. Doctors do not give Type 1s who are using larger doses of insulin metformin, but my guess is that they probably should. I'm not very insulin resistant at all--two or three units is all it takes to drop my blood sugar dramatically, but even so, I can drop my insulin needs by about 1/3 by taking metformin. But here again, the division of diabetes into these two artificial types is hurting people because doctors do not think that a "Type 1" might also have the genes that in middle age would have expressed as "Type 2" had they not also suffered an autoimmune attack.

So it is time we dispensed with the artificial division of diabetes into Type 1 and Type 2. Let's admit that "Diabetes" is really nothing more than a symptom--high blood sugar--and that the causes of that symptom are many and not mutually exclusive.

When the damage is to the immune system, we get autoimmune attack on the beta cells. When the damage is to the genes that regulate insulin resistance in the muscles--and possibly mitochondrial function, we get another form of diabetes, when the damage is to the genes that regulate the beta cell's response to rising glucose levels in the blood we get secretory defects, when the body suffers genetic damage thanks to exposure to chemicals in the environment we get yet more blood sugar abnormalities, and like the unlucky LADAs, some of us get more than one of these problems going on at once.

And those of us who do have abnormal glucose metabolism should resist the temptation to divide people with diabetes into types and to use this typology to define some of us as blameless and others as blamable diabetics.

That kind of division helps no one. All of us should be putting our efforts into ensuring that EVERY person with diabetes gets the kind of excellent, health-preserving treatment that so few of us currently get from the doctors, nutritionists, and drug companies who see us as little more than a huge profit center.

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