Wednesday 30 August 2017

Health - HbA1c: THE blood test

Summary: Get your HbA1c tested! Values of 30 mmol/mol (4.9%) and above indicate increased glucose in your bloodstream giving a higher chance of heart disease as well as diabetes and a whole list of other undesirable possibilities like eye/nerve/kidney problems that go with it. The safest values may be as low as the 25 - 29 mmol/mol (4.4% - 4.8%) range. The easiest way to lower your hba1c result is to eat fewer carbs.


The HbA1c test indicates how much glucose has been in your bloodstream over the last 2 or 3 months. Higher numbers indicate increased risk of various nasties including heart/circulation problems (and other conditions) as well as the more obvious glucose/diabetes problems it is usually used for.

Diabetes
A value of 48 mmol/mol (6.5%) or above is used as a diagnosis of diabetes, and a value of 42 mmol/mol (6.0%) or above indicates that you're probably heading towards it (they call this "prediabetes"). If you're at 40 or so, your doctor will probably say you're OK, but lower values are better as you can see below ...

Heart/circulation problems
The ARIC study monitored a group of US patients from 1987 onwards. In 2005 this analysis looked at whether Hba1c was an important factor.


A is the non-diabetic group and B is the diabetics. The grey dotted lines connect the average values for each fifth of the group and the black lines are trend lines estimated in the study. (I would have been tempted to use a curve for the trend in B, but maybe they had a reason not to do that?)

You can see that in general the risk of heart problems goes up as HbA1c rises, although there is maybe a slight rise at very low values for the non-diabetics. Whether you're a diagnosed diabetic or not, the safest area seems to be right near the low end, at values under 5.0%. The authors estimate the lowest risk for non-diabetics indicated by these results is around 4.4% - 4.8% (24.7 - 29.1 mmol/mol), so well below the 42 mmol/mol level where your doctor might start telling you to worry about diabetes. If you can get it down to this kind of level from just below 6.0%, this study suggests you might reduce your chances of heart disease by half or even two thirds!

Alzheimer's, Parkinson's and other neurological problems
This study title days it all:
"Elevated HbA1c is associated with increased risk of incident dementia in primary care patients."
Just to clarify:
"The T2DM diagnosis per se did not increase the risk of either ACD or AD. Higher levels of HbA1c are associated with increased risk of ACD and AD in an elderly population."

Cancer (except prostate):
Does cancer risk increase with HbA1c, independent of diabetes?
"Results:
The data reveal that chronic hyperglycaemia correlates with increased cancer risk for a number of cancers, except prostate cancer. Evidence is also provided that risk is already increased in the pre-diabetic and normal ranges for several cancers."

You can see that high hba1c values are related to a whole list of unpleasant health outcomes. 🙁

What to do
See your doctor to get the hba1c test. If it's higher than you want, e.g. 30+ mmol/mol, eat fewer carbs. When you do eat them, have some fat or vinegar as well to slow down their absorption.



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