I just followed a link left from Michelle Curtis a few days ago on a different thread, leading to a talk on www.diabetes-symposium.org about data from CGM studies in normal people. These were people with an average A1c of 5, about 27 years old, so pretty young and healthy.
Apparently, the normal subjects in this study had BG levels that ranged from 55 to 160, which is a much larger range than I understood to be the case. The average postprandial BG was 100 -165, with 132 being average. The biggest spikes in these non-diabetics was after breakfast, with the spike appearing pretty reliably at around 45 minutes (not 1hour or 1.5 hours). Nighttime glucose was really stable in these people.
I’m not sure how much of this info people are already aware of, but it does make me feel a bit more comfortable about my ranges.
reference -
Christiansen, Prof. J. S., On the occasion of the Annual Meeting of the EASD, Copenhagen, 13-Sep-06, What is Normal Glucose? – Continuous Glucose Monitoring Data from Healthy Subjects
That is an interesting site with some great information. I think it’s important to note that although the spikes were a bit higher than I would have expected, they are very brief. As you pointed out, normal people peak at 45 minutes, so time spent above 120 was minimal in almost all the subjects. In fact, one of the slides shows that on average, the subjects spent only one hour each day between 120 and 140, 10 minutes between 140 and 160 and 2 minutes above 160. That’s a far cry from 2 hours in those upper ranges after every meal. It did make me relax about being 120 after an hour, as this seems to be in the normal range.
Yes, this is possibly one of the most interesting things about blood sugar I have ever found!
I put a screen capture from this presentation on my “normal blood sugar page” that lets you look at it a bit more carefully. It also shows the corresponding insulin and c-peptide levels.
The A1cs of the “normal” people ranged up to 5.4%, if I recall correctly, which may indicate that the higher ones are borderline pre-diabetic.
Here’s the screen capture from that wonderful presentation.
This is interesting, and it confirms some elements that JDRF investigated several years ago, specifically, what they found was that glycemic variability was significantly higher than the prevailing perception was, and that post-prandial numbers were significantly higher as well.
Researchers at the Barbara Davis Diabetes Center in Colorado also found that the amount of time spent in hypoglycemia was similarly much longer than doctors had anticipated.
All of this suggests that coverage for CGMS should become more widespread if we hope to attain meaningful improvements in glycemic control, but the reality is that most patients struggle to obtain coverage for these devices and the overpriced sensors which accompany them. The reason is because most insurance companies do not make decisions based on long-term results; they know few patients will remain with them for longer than the average of 5 years, therefore it does not make financial sense to cover these devices. Until we have a significant change in the way we pay for medicine in this country, the outlook looks unclear at best.
