How high does blood sugar have to be to cause eye/nerve/extremity damage?

How high does blood sugar have to be to cause eye/nerve/extremity damage?

Would it be, say, a fasting 6.5 A1C or 100 blood glucose for several months? Ballpark figures are fine.

??? 6.5 A1C and 100 fasting blood glucose is stellar for a diabetic.

Fasting A1C makes no sense to me. A1C is a measure of blood glucose levels over several months, not at a particular moment.

Ooops you’re right! Fasting blood sugar. A1C is A1C.

I think probably you would be talking years for damage to occur.

I don’t have time to search now, but we had this discussion in the last 4 months. Some digging out to locate the thread easily.

There were some good cites given that numbers *around there *are negligible risk.

But don’t forget, 6.0 to 6.5 to 7.0 are big differences in A1C. And any given test run is only accurate +/- 0.5 ish. So if your 6.5 is really a 6 you’d be fine for decades, but if it’s really a 7 you’d expect beginning signs of deterioration in a few years at most.

The big unknowable is whether your 6.5 today turns into 7.5 in 2 years or in 20.

I hope I’m not jus whistling in the dark here, but I thought 7 was tolerable and, in fact, was the just-made-it line until fairly recently. (Me 7.1.)

There was a good thread on “peripheral neuropathy” that may be of some help.

Is it too much of a hijack to ask for a nutshell summary of the “how/why” of the damage? What’s the mechanism where sugar in blood → cellular damage?

Again, if I should wander off to one of the afore-mentioned previous threads, please feel free to let me know. :slight_smile:

Imagine there’s a hole in the fill pipe to the gas tank of your car, and if you overfill it, the extra gas spills into the trunk. Generally hard on the things in the trunk, and if any of the bodies back there has a still-lit pipe in his pocket, this could be very bad. As the trunk gets filled more and more, the fumes eventually work their way out into the passenger compartment, and that’s generally very bad.

In terms of the body, too much glucose has some sort of abrasive effect on all the small blood vessels, whether they’re in your eyes, the tips of your toes & fingers, etc. The smallest blood vessels supply blood to the nerves in these areas, so disrupting the blood vessels (and the flow of blood) causes the nerves to not work so well.

Nevertheless the risk and consequences of hypoglycemia make the tight control target more like 7.2:

IN addition to the microvascular issues **Ethelrist **mentioned, high glucose levels promote atherosclerosis.

So compared to serotypical folks, more plaque builds up in diabetics’ blood vessels, eventually leading towards heart disease, heart attacks, etc. This is the acute off- ramp for diabetic mortality.

The fact diabetes also tends to exacerbate blood cholesterol regulation means diabetics tend to have more of the raw ingredients of atherosclerotic plaques floating around in their blood as well.

There are a lot of synergetic reactions going on in there, and they all lead towards worse overall outcomes.

You are by far the pro here; I’m a gibbering idiot spectator by comparison. So a question if I may …

IMO …

I’ve seen that study and other similar ones quoted a bunch. What they seem to be saying is that since hypoglycemic events can be promptly crippling or fatal, they’re willing, from a statistical perspective, to accept greater A1Cs & more long-term damage to keep folks away from the prompt risks of acute hypoglycemic episodes.

Which may very well be a very valid tradeoff on a public health statistical basis, but may not make sense on an individual basis.

My thinking goes like this: There are some diabetics who need insulin or other medications that make hypoglycemia a very real risk. Or folks whose overall health, mental condition, or diabetes management skills are flaky enough that acute hypoglycemia is a real risk. For those folks, it makes complete sense to carefully walk the line between acute hypo- and chronic hyper-glycemia. And thereby to accept considerable chronic hyper- to avoid the acute hypo-.

IMO, there is another class of diabetics who, due to lesser severity of disease, different drug regimen, better management skills, etc., have essentially zero risk of acute hypoglycemic events. And, ITSM that for that group, there is zero advantage to accepting high A1C and chronic hyperglycemia. IMO, those folks’ goals ought to be minimum A1C, and minimum severity and time of post-meal elevated BG. Ideally this group could diet, exercise, and medicate to normal or near normal daily blood glucose profiles. And be totally safe from hypoglycemia in doing so. And thereby achieve normal or near-normal diabetic comorbidity / co-mortality.

The challenge, IMO, is that there aren’t studies which treat these two patient groups separately. And so the standard advice which is doubtless helpful to the first group is (IMO) harmful to the second group.

That may be because the second group is a figment of my imagination. Or it may be that there’s really not a clear dividing line between them and the acute hypo risk group. Or maybe even because all the studies are ignoring these folks as not really ill enough to worry about. IOW, they’re not thought to be much of a public health issue at all.

Finally, this last group may be healthy enough that it’s hard to design a study sensitive enough to detect the difference in outcomes over a short enough term to be practical.
Given all the above surmise, does anyone have any relevant info to add or subtract? Any research support for (or stake through the heart of) my theory?

Purely an anecdote, but here goes:

The correlation between being excellent at diabetic management and avoiding hypoglycemia is not absolute. My spouse has a form of diabetes that makes hypoglycemia more likely than most with Type II. Even though he has had excellent A1C’s, lost 40 pounds and kept it off for nearly a decade, improved his triglyceride numbers, and basically has done everything correctly for many years he is STILL more prone to hypoglycemia than most with Type II. He deals with it by being very observant and getting something to eat as soon as he shows any sign of blood sugar that’s too low.

So sometimes you’re just out of luck. Remember, the whole reason someone has diabetes in the first place is because a production/regulation system is malfunctioning. Depending on which part of the system is broken you might well get someone completely compliant with medical directives, medication, diet, and everything else but still having terrible problems. And, indeed, there is a term for those people: “brittle diabetics”.

Getting A1C to 7 or below is the goal of a Type II Diabetic, such as me. I’m lucky in that I was able to bring it down from my initial (on diagnosis) 12.8 result to the last couple of years all being between 6.2 and 6.8.

I got home from work and ate about 7 ounces of blueberries (yum!) and just now tested my blood sugar at 112.

I suffered peripheral neuropathy at least 7 or 8 years before my glucose rose above 7 mmole/l (126 mg/dl) and my A1C was mostly below 6%. And my fasting glucose is now below 6 and the A1C is about 5.5% and the neuropathy is getting worse all the time. A neurologist told me this is not at all unusual.

That is a crappy chart.

http://www.ladalife.com/wp-content/uploads/2013/04/chart-professional-about-a1c-risk.gif

The risk of eye damage is about 20x higher with an a1c of 12 vs 6.

Oh you are very right, and such was recognized in the link I provided, as can be seen by putting the quote I excerpted in a broader context: