Deus - so is Diabetes progressive, or not? I thought the Jury was still very much out on this one!
It depends on your definition of 'progressive'. I don't think it's a case that everyone's diabetes inevitably gets worse, which is the usual definition. However, if your control hasn't been great for say, 20 years, I think you'll probably still be at risk of complications even if you get perfect A1Cs for the next 20 - it's just that you will ultimately be at a lower risk than if you didn't have great control. So the point always remains - the better your A1c, the better your outcome, although I don't think anyone can guarantee that below a certain A1C, you're complication-proof. As has been alluded to, standard deviation also seems to play a role. And as for the specific retinopathy/pregnancy issue here, I don't know enough about the relationship between the two to make a meaningful comment but I do know that retinopathy has a relationship with blood pressure, so A1C alone isn't necessarily a good predictor.
I think it's luck or your genes or something? God knows.
There's several theories around because it does seem that some people who've had poorly controlled diabetes for decades have better outcomes than some who've only had it for a couple of years.
There's three I can think of, off the top of my head. In the first instance, many those on insulin up until the 1980s used to only have maybe two or even one injection a day (I know, I'm teaching you to suck eggs here, sorry!). That could mean that the SD for such people used to be a lot lower - if a smaller SD means fewer complications, that's a good thing.
Secondly, I seem to recall reading something about vitamin B deficiency in people with diabetes - the stats broadly correlation with the percentage of calculations ie. something like 75% of people with diabetes are deficient in B vitamins, while 75% of people with diabetes have complications. Might just be a fluke or coincidence, but maybe B vitamins have some role to play - after all, they're associated with both metabolism and the nervous system, both of which are affected by diabetes.
Finally....those who've had diabetes for a long time most likely started on animal insulins. Animal insulins contain c-peptide, which is a byproduct of insulin production and is associated with the vascular system - it keeps blood vessels supple and springy. People with T1 do not produce c-peptide. Furthermore, synthetic insulins have the c-peptide removed. It's not a leap of logic to suggest that those on animal insulins might have had a better run of it despite potentially having poorer A1cs. I'm sure Sue will have a lot to say on this!
Part of the issue is that T1s are actually deficient in three compounds - insulin, c-peptide and amylin. We may also potentially be deficient in GABA as well, which influences mood and muscle tone - GAD antibodies, which are partially responsible for causing T1, also disrupt production of GABA. My theory is that T1s who replace ALL of what they're missing (other than just the insulin) are likely to enjoy better outcomes. Incidentally, amylin plays a massive role in reducing blood glucose spikes by controlling digestion, meaning you eat less AND get fewer high blood sugars. It'd probably be an ideal medication for T1s who are worried about putting on weight or getting post-prandial spikes (ie. everyone with T1). In fact it is - it's available in the States as Symlin but NICE seems to be dragging its feet over its approval and most of the doctors I've spoken to have never even heard of it.
