If you had bothered to read past the headline, 1,800 dignosed diabetics (at start of study. Their average a1c was 7%.) are also included. As well as over 1,000 (not yet diagnosed) people above an a1c of 6.5% (some far far above), studied over 10 years. If they aren’t diabetic, I’m not sure I understand the term anymore! Also, 3,800 people who began the study in at least pre-diabetic range 6-6.5%
If I went to a doctor with an a1c of 6.3%, and stayed there for years, I don’t think they’d say “You aren’t diabetic! You’re completely normal!”
As for hormones, too much insulin seems to have a negative effect. I don’t know about glucagon, but some diabetics have too much, others too little, so hard to say.
The lack of epinephrine response seems to be minor overall.
Outside hormones, tissue resistance to glucose uptake may be a factor.
As well as recurrent hypoglycemia (which would vary a lot among diabetics, being very rare for untreated ones).
Hypoglycemia is partially why I think the “normal” people with a1c <5% have such an increased risk of illness according to the study.
Effects of hyperlipidemia, obesity, cholesterol, blood pressure, smoking, etc. should all controlled for in this study.
There are other studies that back up this one, but a 10+ year study of 30,000 people with a1c 4-10%+ is quite comprehensive!
[SECTION EDITED into new thread: How Glucose Variability impacts HbA1c]
@Sam the study that found the close, linear relationship between a1c & average glucose was quite rigorous. But there are indeed about 3 big, legitimate criticisms of it.
One relevant one is that the original study was only of people with good control, so we don’t know if or how GV factors into it (other than the one study above)!
Later I’ll try to make a thread about A1c validity and meaning for you and Jen, and another one about BG/a1c ranges and their effects for Eric.
It’ll just make a mess of this Glucose Variability thread.