R M Cullen
MD MSc MFM BA DipStats DipProfEthics
|elite athlete development||diabetes reversal||genome topology||evolution|
|tamaki sports academy||diabetes blog|
How is type 2 diabetes or pre-diabetes diagnosed?
The standard way of diagnosing type 2 diabetes or pre-diabetes is by a blood test measuring the A1C level. A second way is a blood test measuring fasting glucose. There is a third diagnostic test, the glucose tolerance test, but that is no longer in common use. Type 2 diabetes can also be diagnosed by an elevated random glucose when symptoms of diabetes are present. But this never (or almost never) occurs with a normal fasting glucose and a normal A1c level.
|test||normal||pre-diabetes||type 2 diabetes|
|HbA1c||40 or less||41-49||50 or more|
|fasting glucose||6.0 or less||6.1-6.9||7.0 and above|
These are the criteria used in New Zealand. They are not the USA or WHO criteria. In the USA an A1c of 48 is diagnostic of diabetes. In New Zealand the HbA1C is measured in mmol/mol and fasting glucose in mmol/l
The fasting glucose level is the concentration of glucose in the blood after 10-16 hours of no intake by mouth (or other means), other than water, for 10-16 hours.
Some glucose in the blood attaches itself permanently to red blood cells, forming HbA1c. As red blood cells live for around ninety days the A1c level is a measure of the average serum glucose level over the previous three months.
If either the A1c or fasting glucose level is in the diabetic range, and is still in the diabetic range when that test is repeated, then type 2 diabetes is diagnosed.
If one or other of the A1c or fasting glucose is in the pre-diabetic range, but neither is at the diabetic level then pre-diabetes is diagnosed. Pre-diabetes is important for three reasons
Does obesity cause type 2 diabetes?
The truth is a little more complicated than a simple 'No', but one of the biggest myths put out by the diabetes/anti-obesity industry is the one that has obesity causing type 2 diabetes.
Type 2 diabetes is the result of excess Beta cell mortality. The pancreas has too few Beta cells to produce the insulin required to maintain blood sugar levels at normal levels twenty-four hours a day. Doctors know, and have known for many years, that fatter young people have a greater Beta cell mass than lean young people. The evidence for this is autopsy studies of young people. In the same way that weight training increases muscle size and mass, adding fat storage cells to a human body increase the number of Beta cells.
There is no question that fatter people are more likely to develop diabetes, but only a minority of fat people become type 2 diabetics. Obesity is a risk factor for type 2 diabetes, but a risk factor is not the same thing as a cause. Here is a simple example - short stature is a risk factor for poor reading and writing skills. Short people are less literate than taller people. However, shortness is not the cause of illiteracy. Children are short, and the reason they are less good at reading and writing is that they are still learning these skills.
What about insulin resistance?
Over time, we need more insulin to shift the same amount of glucose from the blood into cells. This phenomenon is called insulin resistance and its appearance is the tipping point to type 2 diabetes in most people.
The walls of our cells act as a barrier to separate the contents of cells from the fluid around them. The analogy is not perfect, but the cell wall can be seen as a filter that requires insulin in order to work properly. The cell requires a certain amount of glucose for energy every minute of every day. As the filter deteriorates it needs more insulin and it also needs a higher concentration of glucose in the blood in order to pass the same amount of glucose into the cell. The elevated fasting glucose level of type 2 diabetes is present because of problems with the cell wall filter. The higher level is needed in order to pass the same amount of glucose through the cell wall.
What is reversal?
Imagine Sally, whose A1c level in March was 56 and whose fasting glucose was 6.4. She was diabetic. By September her A1c level has fallen to 42 and her fasting glucose to 6.2. Has her diabetes been reversed or is it just well controlled?
Sally no longer meets the criterion that led to her being diagnosed with diabetes. She no longer has type 2 diabetes. The condition has been reversed. She is pre-diabetic.
However, there is no guarantee that Sally will not develop diabetes again in the future. Many illnesses are like this - gout, depression, the 'flu, stomach ulcers, broken bones, and so on.