RBC shorter lifespan, lower than expected glycation, and complications

[finsit]

Having a shorter RBC lifespan means that your estimated HbA1c will be lower than the actual value. This is because of fast turn around of RBC and having less glycation as compared to RBC with a normal lifespan of 90-120 days. I have G6PD deficiency where my calculated RBC is much shorter so i always have lower than normal A1c results. Now lower a1c means lower glycation so does that mean that diabetic complications that happen due to higher glycation will be reduced the similar %age of having lower a1c or this decrease is just a measure of a1c and not the overall glycation in the body that puts me under the equal risk? I hope i explained it well, but ask me if you need further information.

 

[JohnEGreen]

I believe it means your A1c measurement is skewed and cannot be relied on to give a true measure of glycation your doctor should maybe consider using a different test such as the Fructosamine test.

 

[finsit]

I believe it means your A1c measurement is skewed and cannot be relied on to give a true measure of glycation your doctor should maybe consider using a different test such as the Fructosamine test.

Yes, that is given. My question is does this reduced glycation reduced impact on diabetic complications because RBC turn over time is reduced?

 

[JohnEGreen]

There is not a reduction in glycation just that certain red blood cells have died before their glycation could be determined hence it impossible to tell what the level has been over a three month period it may have been lower or higher but the likely hood is that it would have been higher.

Edit to clarify the A1c figure does not indicate a lower glyceation level as it is an erroneous result and inaccurate.

 

[HSSS]

The basis of the hba1c is that normal levels are assessed and set on the assumotion of 12 weeks of exposure. So if you haven’t had that 12 weeks there’s no way to assess if your exposure is normal or not (unless you use a different test) and the test is flawed. Kind of like doing a lateral flow with orange juice and thinking the (false) positive means the same a real one done according to the test requirements.

 

[finsit]

There is not a reduction in glycation just that cerain red blood cells have died before their glycation could be determined hence it impossible to tell what the level has been over a three month period it may have been lower or higher but the likely hood is that it would have been higher.

Hi John thanks, but doesn't the same RBC when glycated cause issues in small blood vessels, so somehow if they are being turned around and being replaced by fresh RBC's so it not even reduces my a1c but also reduces my overall glycation as well? that is what is being measured here. Makes sense?

 

[JohnEGreen]

In a word no.

The glycated level will be what ever it was over a three month period but you cannot tell from the test what that level was.

The A1c is produced when glucose attaches to Haemoglobin a shorter lifespan of the blood cell means that maybe less glucose will have attached to the protein but the level of glucose in the blood stream will be unchanged just less of it will have attached the reaction of glycation takes a known average over time to take place if you reduce the time the formula no longer gives an accurate result and is therefore useless for detemining how much glucose was present in the bood and it's the glucose levels that do the damage the A1c is just an indicator of how much glucose was present over a set amount of time 12 weeks shorten the time the formula no longer works. It is a standardised test.

 

[HSSS]

Every cell gets glycation doesn’t it? We just use rbc ones as the measure. So yes whilst your circulating rbc are less damaged by it (because they don’t get so long to be) the rest of your cells are still bathed in whatever the levels of circulating glucose are. And that same glucose is still doing it’s damage to other cells as it floats around. Or this is my take on it anyway. Not that I have anything to back up my opinion I would admit.

 

[JohnEGreen]

Every cell gets glycation doesn’t it? We just use rbc ones as the measure. So yes whilst your circulating rbc are less damaged by it (because they don’t get so long to be) the rest of your cells are still bathed in whatever the levels of circulating glucose are. And that same glucose is still doing it’s damage to other cells as it floats around. Or this is my take on it anyway. Not that I have anything to back up my opinion I would admit.

Except a HbA1c test will not tell you what the average glucose level over the shorter time scale was, it could be significantly higher or lower than assumed and a higher glucose level over a shorter time may be more danaging than a lower level over a longer time but you have no way of knowing what the level was, that is why I said a Fructosamine test should be considered as it will give a relatively accurate indication of the average glucose level over a shorter time period by measuring the amount of Fructosamine in the blood in the case of the A1c the average glucose level is inferred from the amount of glyciation that has taken place over a set period of 12 weeks .

 

[HSSS]

Except a HbA1c test will not tell you what the average glucose level over the shorter time scale was, it could be significantly higher or lower than assumed and a higher glucose level over a shorter time may be more danaging than a lower level over a longer time but you have no way of knowing what the level was, that is why I said a Fructosamine test should be considered as it will give a relatively accurate indication of the average glucose level over a shorter time period by measuring the amount of Fructosamine in the blood in the case of the A1c the average glucose level is inferred rom the amount of glyciation that has taken place over a set period of 12 weeks .

Err I’m agreeing with you. Hba1c won’t be accurate.

 

[jonathan183]

Glycation of proteins takes place and is related to the glucose concentration. The fact your red blood cells live for a shorter time period does not change the glucose concentration, so does not affect damage done to proteins in your body.

 

[JohnEGreen]

Err I’m agreeing with you. Hba1c won’t be accurate.

Sorry so you are I just get a bee in my bonnet some times and the brain fog since covid sometimes befuddles my comprehension though my granson says he thinks i'm just senile I hope he was joking.

 

[HSSS]

Sorry so you are I just get a bee in my bonnet some times and the brain fog since covid sometimes befuddles my comprehension though my granson says he thinks i'm just senile I hope he was joking.

Oh I hear you there. My brain is more fried than normal this last month since covid. My son was only saying yesterday I was heading for a care home (in jest I hope as I’m only a little past my half century)

 

[Mbaker]

Really interesting question. I don't know the answer, but an observation which may point you in the same direction I have gone, which is in short just focusing on fasting blood glucose and the starting position before a meal followed by the postprandial rise

What I found was that my best HbA1c was achieved with higher fbg, and higher estimated A1c's by Freestyle Libres and 6 regular monitors (2 of which were calibrated with professional surgery grade units). I found that I got a lower fructosamine (by 11 points) with higher A1Cs. This of course is back to front. The tests were carried out on the same blood draws, the same company and on the same assay. Now I have given up trying to understand how I can drop a full point, test to the point of obsession and still get discordant results; now I don't bother focusing on getting in the late 3's, but am comfortable in the mid 4's.