Unless we quote sources all the myths about diabetes continue. These are the myths that allow people to declare that T1D’s can’t be allowed to do stuff that other people can; like, famously, the British Sub-Aqua Club [BSC: UK Diving Information].
There’s more than enough evidence on this thread that disputes the original claim. This is not wikipedia. A lot of this is original research and it needs to be because if you go with the wikipedia approach you just end up with a distillation of the current myths and legends.
Personal experiences quoted on this page are hard scientific evidence. Repeated quotes by one or other bunch of do-gooders are apocryphal at best. See the evidence of elver above; if you take both that (DMV) approach and this apocryphal statement from the Dutch ([https://www.diabetestype1.nl/bibliotheek/dagelijks-leven/319-nieuwste-inzichten-over-hypo-s-en-hypo-unawareness):
Na ongeveer 5 jaar diabetes type 1 werkt de reactie met glucagon niet meer.
[TR, Google:] After approximately 5 years of type 1 diabetes, the reaction with glucagon no longer works.
Then apparently all T1D’s should be banned from driving after 5 years. Notice that the quoted Dutch assertion is an absolute statement (“the reaction with glucagon no longer works”), assuming Google Translate got it right (my Dutch is extremely limited but the translation seems correct; “niet meer”.)
I can assure you that I have been a T1D for more than “ongeveer 5 jaar”, like 47 years, and I have a physical glucagon response that works. Mine hardly ever kicks in because I have a mental low blood sugar response that also works and I know what it means. My non-diabetic wife is only now developing the mental “I need something to eat” response; her BG will drop to around 60 mg/dl, she notices then, I notice at 70-80. Specifically at 8:55AM while writing this my hypo-awareness just triggered; my G6 reads 88mg/dl descending, my Contour Next reads 77mg/dl and my hypo-aware self says “eat something”. I looked at the G6 and meter because my mind hypo trigger happened, not the other way round.
So where is the original research that the OP asked for? It isn’t some article on www.diabetestype1.nl, a Dutch analog of tudiabetes. These are all regurgitations of sets of medical opinions derived, maybe, from some original research. All we have at this point is the review paper identified by Boerenkool, the OP:
This review will focus on the more recent developments in our understanding of the mechanisms that underlie the sensing of hypoglycaemia in both non‐diabetic and diabetic individuals, and how this mechanism becomes impaired over time.
This is a review paper; a scientist summarizes a set of other original research papers so that other scientists don’t have to read (or, indeed, understand) them. It’s 11 years out of date. It has received 39 citations, that would be low for original research but it might be how it goes for review papers (readers will often cite the original research not the review).
Part of the problem is the “pay for access” thing and the fact that there is so much bad scientific research that if you don’t have full time (institutional) access and spend it following the research it is difficult to distill the bad science from the good. This is why review papers are useful.
There are two things happening here and it is VERY important to separate them:
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Hypo-awareness. Humans as a group are not hypo-aware because the symptoms of hypoglycaemia (or hyperglycaemia for that matter) are not unique to hypoglycaemia. Hypo-awareness has to be developed and that takes time; evidence, personal (my own and my non-diabetic but blood testing wife.)
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The glucagon response. For T1Ds this seems to change over time to adapt to wider fluctuations in blood glucose, but it’s not clear to me how much it changes. I haven’t seen any evidence to support the Dutch statement above; that it absolutely fails. If it did I would be absolutely dead; so I can simply refute the assertion by typing this (oops, am I a ghost?) This is because when I was first in Oregon I proceeded into the woods with a chainsaw to work off some serious emotional stress and forgot to take my glucose tablets. After cutting a few sticks I became so incapacitated that my voluntary control of my muscles ceased, failed. I had enough control to cut the saw but nothing else. After a while on the ground I was able to get up and return to the house with the normal symptoms of a glucagon response. Just to make it clear; I am not dead.
This is, of course, consistent with Boerenkool’s second quote above, but note that there are still two things here; hypo awareness and when the glucagon response kicks in, what BG level. It makes complete sense to me that T1Ds should develop an increased ability to be aware of hypos at the same time our bodies adapt our physical glucagon response to deal with greater fluctuations in blood glucose. This is good because we don’t want that horrible glucagon response kicking in if we can avoid it; we have the technology. We have the capability to eat glucose tablets; better than glucagon, faster, controllable.
The abstract of that 2008 review paper is also consistent with the changed response. Of course there is always a spin: emphasis added below:
During hypoglycaemia, glucose‐inhibited (GI) neurons may be regulated by the activity of AMP‐activated protein kinase. This sensing mechanism is disturbed by recurrent hypoglycaemia, such that counter‐regulatory defence responses are triggered at a lower glucose level.
So let me rewrite that in a non-judgmental form:
Scientists hypothesise that an AMP‐activated protein kinase regulation of glucose‐inhibited (GI) neurons adapts to the greater fluctuations in blood glucose observed in Type 1 diabetics so that counter‐regulatory defence responses are triggered at a lower glucose level.
If correct this would allow Type 1 Diabetics more time to respond externally to low glucose than observed in less capable non-diabetics. The changes in the levels at which the relevant hormonal response, glucagon production, is invoked along with increased awareness of the symptoms of hypo and hyper-glycaemia mean that Type 1 diabetics are significantly more able to deal with the blood glucose regulation issues after 5 or so years.
Personal experience does refute the assertions made about lack of hypo awareness.