Where did you get that titbit from?
World Journal of Diabetes 2014 June 15; 5(3):282-287, Why do some patients with type 1 diabetes live so long?
I'm sure they didn't mean to imply by the title that they rather wish we didn't!
"Of 400 type 1 patients who survived for fifty years with diabetes, the mean HbA1c was 7.6%(+/-1.4), with some of these patients having HbA1c as high as 8.5-9%. None had an HbA1c below 7%."
And that's the real life proven effect, not a theoretical effect of HbA1c. The "None...." may be psychologically challenging for us, but that's why it probably deserves a bit of attention.
For people who don't want to read the whole scientific paper,
the significant clinical factors are in Table 2 just before the conclusion. Very heartening study. Nice to see something positive about longevity instead of all doom and gloom. And most of the factors are highly 'manageable.' You don't need to be super-diabetic to pull it off!