2 distinct types of pre-diabetes

Specifically read the paragraphs under “Question 1…” and “Question 2 …”
(also described here: http://care.diabetesjournals.org/content/29/5/1130.full)

There seem to be 2 types of prediabetes: IGT and IFG. (Some have both)
Both types have a high risk of progressing to overt diabetes and its complications, barring intervention.

IFG = “impaired fasting glucose”
IGT = “impaired glucose tolerance”

IFG is defined as FBG 100~125.
IGT is defined as 120 min. OGTT > 140.

Those with only IFG have some liver insulin resistance but not muscle insulin resistance.
Those with only IGT have it the other way around.

Liver insulin resistance results in the high fasting glucose.
Muscle insulin resistance prevents muscle from absorbing glucose 60-120 min after a meal.

In response to an OGTT those with IFG-only also have a weakened first phase insulin response to a glucose load (0-10 mins), somewhat weak early phase (10-30 mins), but normal late phase (60-120 min) response. As a result they will have a high BG spike 30-60 minutes post meal but look more normal at 90-120 mins.

Those with IGT-only have weak insulin output including a weak late-phase response, especially relative to the muscle insulin resistance. Thus their 120 min OGTT result is >140. However the lack of liver insulin resistance means the liver does not produce excess glucose during sleep.

I will have high 45-60 minute BG spikes with a modest carb intake (>50g), but it’ll be down to 100 at 90 min and in the 80s at 2 hrs so my post-prandial response fits the IFG profile above, although my waking BG without meds has been in the high 90s since forever instead of 100-125. Also, IFG-only individuals tend to be obese, while I’m lean (as per DEXA scan, 19% overall bodyfat and 20% android (abdominal) fat). LDL, BP, and Trigs are all low…

Additionally those with IFG tend to have high fasting insulin, while mine is low (~5.0).

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I was first diagnosed a year ago with IFG; but am not overweight at all and have low LDL, BP and Trigs when on thyroid meds. Before fasting readings rose last year, I passed 3 GTT tests in 2007, 2008 and 2010. Found Positive for GAD antibodies last year, so unlikely type 2.

Interesting. But I don’t actually believe in “Pre-diabetes” of any kind. To say that one has time to get control of one’s diabetes is reasonable and a good thing. But pre-diabetes is just a heads’ up terminology invented by those unwilling to dx folks appropriately for whatever reason.

I find it almost as silly as the concept of “reversing” or “curing” diabetes–of any type. I think motivations for using the term can vary widely depending on circumstances. And I do, believe me, believe that there are now many more proven types of The D than when I was dx. Perhaps these studies will lead to more and better definitions and treatments.

I have seen many examples of the dx making folks sit up and pay attention—to get more testing done, etc. So it’s not all bad. But if there is no follow-up, it can be very bad indeed…Blessings…Judith


This is really interesting! Thank you!

@Judith_in_Portland…There would have been no further testing for me, had I not pushed all the way. Ever felt like Sisyphus?

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IMO the term “pre-biabetes” is useful as a term to identify the early stages of diabetes.

However I do think that it would be MUCH better to describe a patient in terms for the different aspects of diabetes:

  • IFG or IGT or both as per the article
  • hepatic insulin resistance, mild, moderate, advanced
  • muscle insulin resistance, ditto
  • poorly controlled glucagon output
  • mildly, moderate, very weak first phase insulin response
  • ditto, early phase
  • late phase
  • poor incretin response
  • autoimmunity
  • which gene polymorphisms are present
  • etc

It’s clear the term “diabetes” is merely a catch-all term that describe a symptom (hyperglycemia) caused by multiple epigenetic factors. The most appropriate treatment will depend on which combination of the above the patient has.

I myself had reactive hypoglycemia 9 years ago, which developed into poor sugar/starch tolerance today. I’m lean and fit, have no LADA antibodies, and with <40g carbs per meal, and Metformin and/or ALA, my morning BG is in the 80s (high 90s without Met/ALA). However I fit the description of IFG from the article. Additionally, how high my BG spikes after meals seems to vary from meal to meal… still trying to figure it out.

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