what is "normal " Hba1c in non diabetic populations

[CherryAA]

I thought people might be interested in this article.

http://www.mendosa.com/blog/?p=366

Apparently 99% ( 3 standard deviations) of people without diabetes will fall within a normally distribute range of 4.5 % to 6.0% ( but skewed to the higher end.

At 95% (2 standard deviations) that would be 4.7% - 5.7%

Optimal per Dr Bernstein would be 4.2%- 4.6% reflecting the fact that just like insulin levels, the current standard diets do not lead to optimal health for anyone.

 

[Squire Fulwood]

I am going to make a stab at this. Since 42-48 is considered pre diabetic then anything below 42 can be called normal. I have heard of people in the 20's but exactly where the top of the curve is I don't know.

 

[phdiabetic]

On my blood results, the reference range is given as 4.0%-6.0%. My doctor told me that many normal people have an HbA1c higher than mine (4.8%) which makes me very suspicious, because I don't spend much time being low, and I spend quite a bit of time higher than normal, so why are all these normal people doing worse than I am? I put a lot of effort into my control, but I am certainly nowhere near perfect, so why are all these supposedly normal people getting higher numbers than a struggling type 1? Do they eat a lot? Are they on their way to developing diabetes? I was even told that a lot of people around my age (teens, early 20s) have numbers higher than mine. How?? It honestly makes me wonder whether I have some problem that artificially lowers HbA1c, because while I do try my best, I feel like I just can't be better than nondiabetics.

 

[CherryAA]

On my blood results, the reference range is given as 4.0%-6.0%. My doctor told me that many normal people have an HbA1c higher than mine (4.8%) which makes me very suspicious, because I don't spend much time being low, and I spend quite a bit of time higher than normal, so why are all these normal people doing worse than I am? I put a lot of effort into my control, but I am certainly nowhere near perfect, so why are all these supposedly normal people getting higher numbers than a struggling type 1? Do they eat a lot? Are they on their way to developing diabetes? I was even told that a lot of people around my age (teens, early 20s) have numbers higher than mine. How?? It honestly makes me wonder whether I have some problem that artificially lowers HbA1c, because while I do try my best, I feel like I just can't be better than nondiabetics.

I think that as we look closely at our numbers it is easy to simply not appreciate the extent to which high sugar / carb diet is affecting everyone - not just those diagnosed with diabetes. That is why ( forT2 at least) I consider myself " lucky" at least I know what is happening to me. Most of the population is having the same things happening albeit perhaps to a smaller degree, but they have no idea.

 

[ringi]

I would love to know the HBAC1 level that 95% of the people who have never had diabetes, CVD, weight issues, strokes, censor or Alzheimer’s disease have remained under. This may tell us how low we need to be to avoid health issues that seem to be related to insulin resistance.

But I don’t know of a large dataset that has a long history of HBAC1 results with enough people who are now “old” in it to give us this data. The “nurses’ health study” in the USA may be closest to having the data.

The other interesting option would be to take people who are in the bottom quartile for insulin resistance and see what their medium HBA1C is. Or do it based peopole who the Knoff inslin responce curve shows have very low risk of every getting Type2.

 

[Bluetit1802]

I would also like to see some notice taken of the unreliability of the HbA1c, which is becoming more and more well known. Blood tests on each participant could give some markers as to whether their HbA1c is likely to be elevated or reduced due to non-standard red blood cells. Or some sort of data from CGMs. Who is to know whether any of those participants had accurate HbA1cs or skewed ones? There is no such thing as normal when it comes to individuals.

 

[ziggy_w]

Thanks, @CherryAA for posting this. Really interesting information.

If my knowledge of statistics doesn't fail me, the mean HbA1c (the top of the curve) should be 5.2% (33 mmol) provided the data are not skewed (i.e. most frequently observed value is to the left or the right of the mean or average). However, based on the interview with Curt the data seem to be somewhat skewed and he says that low values are observed rarely, so the median might be below the mean, thus meaning that maybe 5.1% is the most frequently observed HbA1c.

 

[ringi]

Firstly let remember that most people have accurate HbA, therefore "stats" methods will remove the "noice" from people who don't have when looking at large datasets. (But not on a personal level.)

If my knowledge of statistics doesn't fail me, the mean HbA1c (the top of the curve) should be 5.2% (33 mmol) provided the data are not skewed (i.e. most frequently observed value is to the left or the right of the mean or average). However, based on the interview with Curt the data seem to be somewhat skewed and he says that low values are observed rarely, so the median might be below the mean, thus meaning that maybe 5.1% is the most frequently observed HbA1c.

As no one has a negative AC1 and some people have a very high AC1, clearly the median will be lower than the mean. The only time I ever seen datasets that keeps to a “normal distribution”was in stats classes, but I did not study stats past the first year at university, so did not get into the detailed maths of skewed distributions.

If I recall correctly Prof Tim Noakes says anyone with an AC1 over 5% (31) have issues with insulin resistance so should reduce their carb intake.

 

[Bluetit1802]

Firstly let remember that most people have accurate HbA, therefore "stats" methods will remove the "noice" from people who don't have when looking at large datasets. (But not on a personal level.)

OK, but when we all have our HbA1cs, and similarly when everyone that has them on routine checks, we are branded according to the accepted norm of under 42 or over 47 or whatever this may change to. But this norm isn't applicable to everyone. There may be many people diagnosed with pre-diabetes who actually have T2, and many others diagnosed with T2 who are not actually T2. (this won't be the case if the HbA1c is high of course) Then on follow up reviews we are judged by our HbA1c. A few of us on here are well aware our HbA1c is most likely incorrect, but there must be many more who have absolutely no idea! I have no real interest in my HbA1c levels other than to keep it stable and watch out for upward trends.

 

[first14808]

From my stats classes, normality is the standard deviation. And who wants to be a standard deviant? It also pointed out that populations of people are notoriously challenging when it comes to statistics, because we're variable. Plus populations may be skewed by other factors, ie migration so the population is multi-ethnic with a range of potential genetic factors.

But to me, being diagnosed seems a bit hit & miss and dependent on GP's ordering tests. Mine did, now I'm officially diabetic, but no idea how long for. But knowing T2 is on the increase, and not knowing exactly why, it would seem sensible from a public health perspective to screen everyone routinely. It'd cost a bit, but probably less than it costs for treating/managing complications from undiagnosed diabetics. Plus it'll help researchers as there'd be more data.

 

[Bluetit1802]

But knowing T2 is on the increase, and not knowing exactly why, it would seem sensible from a public health perspective to screen everyone routinely. It'd cost a bit, but probably less than it costs for treating/managing complications from undiagnosed diabetics.

The NHS invites everyone over 40 for a routine health check unless they already have regular checks for some disease or other. In my surgery they do an HbA1c at these checks as they abandoned the Fasting plasma glucose test. I don't know how many they "catch" but I bet it is a lot.

 

[Daibell]

From my stats classes, normality is the standard deviation. And who wants to be a standard deviant? It also pointed out that populations of people are notoriously challenging when it comes to statistics, because we're variable. Plus populations may be skewed by other factors, ie migration so the population is multi-ethnic with a range of potential genetic factors.

But to me, being diagnosed seems a bit hit & miss and dependent on GP's ordering tests. Mine did, now I'm officially diabetic, but no idea how long for. But knowing T2 is on the increase, and not knowing exactly why, it would seem sensible from a public health perspective to screen everyone routinely. It'd cost a bit, but probably less than it costs for treating/managing complications from undiagnosed diabetics. Plus it'll help researchers as there'd be more data.

Hi. Most will not know how long they have been diabetic at diagnosis. GPs use a lot of guesswork initially at diagnosis and don't necessarily do all the tests they could if in doubt - mine didn't. Once your HBa1c starts to be measured then the GP has something to use to decide the best treatment along with any tests done. Most things in nature follow a bell-curve so there is no exact boundary for diagnosis (my wife's natural body temp and blood pressure are lower than the norm for example). Yes, our Western diet has far too many carbs so I would expect it to move the HBa1C average up for the non-diabetics than it would for some other parts of the world and genetics must have a big influence. I don't take my actual figures too seriously but keep my BMI at a good point, have a good diet and with my insulin keep things stable. When on insulin, of course, your HBa1C is what you choose to make it.

 

[Alexandra100]

Yes, our Western diet has far too many carbs

But all traditional diets in poorer countries have even more carbs, being based on, or even consisting of, rice, chapatties, potatoes, bread etc. A difference between us and them might be that we can afford more fat with our carbs, and can afford to over-eat. But whether in fact we are more likely to suffer from diabetes, I don't know. Richer people can also afford to eat LCHC or any other diet we hope will help our diabetes, which is not the case for poorer ones.

 

[Alexandra100]

On my blood results, the reference range is given as 4.0%-6.0%. My doctor told me that many normal people have an HbA1c higher than mine (4.8%) which makes me very suspicious, because I don't spend much time being low, and I spend quite a bit of time higher than normal, so why are all these normal people doing worse than I am? I put a lot of effort into my control, but I am certainly nowhere near perfect, so why are all these supposedly normal people getting higher numbers than a struggling type 1? Do they eat a lot? Are they on their way to developing diabetes? I was even told that a lot of people around my age (teens, early 20s) have numbers higher than mine. How?? It honestly makes me wonder whether I have some problem that artificially lowers HbA1c, because while I do try my best, I feel like I just can't be better than nondiabetics.

This article by Jenny Ruhl might help: http://www.phlaunt.com/diabetes/16422495.php

 

[Resurgam]

I usually went for blood tests for my thyroid when eating a low carb diet - I got to 65 without being detected as a diabetic, and I know that my normal diet of under 60 gm of cars a day completely masks my diabetes. I ate that way for decades when I could get away with it. I have seen quite a few hysterical doctors in my time.
I have done urine tests - never got more than the tiniest change in colour, even just after diagnosis. Not the smallest colour change shown on the tin, the tiniest change of colour my most excellent colour sense could detect easily.
I think that my Hba1c of 41 equates to 5.9 - but the last test I had was 6 months ago. I would assume it has gone down since then.

 

[ringi]

But all traditional diets in poorer countries have even more carbs, being based on, or even consisting of, rice, chapatties, potatoes, bread etc.

Firstly this is not true, as most traditional diets contained lots of hunted meats until we invaded them and introduced the concept of land ownership etc. Also, these carbs are much less processed then ours, even a traditional "bread" is much lower GI then a bread made with any floor you can buy from a UK supermarket. (Consider the difference between sweet potatoes, that have very high fibre, and our potatoes that have been bred to be as "white" as possible.)

 

[Mr_Pot]

I have done urine tests - never got more than the tiniest change in colour, even just after diagnosis. Not the smallest colour change shown on the tin, the tiniest change of colour my most excellent colour sense could detect easily.

Glucose does not normally appear in urine until the level in blood exceeds 10 mmol/L so a urine test is not a good test for diabetes.

 

[Mr_Pot]

Firstly this is not true, as most traditional diets contained lots of hunted meats until we invaded them and introduced the concept of land ownership etc. Also, these carbs are much less processed then ours, even a traditional "bread" is much lower GI then a bread made with any floor you can buy from a UK supermarket. (Consider the difference between sweet potatoes, that have very high fibre, and our potatoes that have been bred to be as "white" as possible.)

Depends how you define traditional....

Today, rice (Oryza species) feeds more than half the world's population and accounts for 20 percent of the world's total calorie intake. Although a staple in diets worldwide, rice is central to the economy and landscape of wider East Asian, Southeast Asian, and South Asian ancient and modern civilizations. Particularly in contrast to Mediterranean cultures, which are primarily based on wheat bread, Asian cooking styles, food textural preferences, and feasting rituals are based on consumption of this vital crop.

Rice grows on every continent in the world except Antartica, and has 21 different wild varieties and three distinct cultivated species: Oryza sativa japonica, domesticated in what is today central China by about 7,000 years BC, Oryza sativa indica, domesticated/hybridized in the Indian subcontinent about 2500 BC, and Oryza glabberima, domesticated/hybridized in west Africa between about 1500 and 800 BC.

 

[Alexandra100]

Firstly this is not true, as most traditional diets contained lots of hunted meats until we invaded them and introduced the concept of land ownership etc. Also, these carbs are much less processed then ours, even a traditional "bread" is much lower GI then a bread made with any floor you can buy from a UK supermarket. (Consider the difference between sweet potatoes, that have very high fibre, and our potatoes that have been bred to be as "white" as possible.)

That was then, not now.

 

[ringi]

Wheat changed greatly in its chemical makeup in the 1950s (in the west) when transactional varieties were replaced with new high yielding low growing varieties (often F1 hybrids). I know a lot of work was done on breeding new varieties of rice to increase yield, but I don't know when they come into use.

Steal grinding of wheat enabled most of the fibre to be removed, even when this fibre is added back, it does not seem to slow down the absorption of the carbs as well as transitional grounding of flour.

Remember that diabetes is becoming a much bigger issue in the 3rd world than in the UK or USA.