Article by Dr. Sreejith N. Kumar, Chairman of the Indian Diabetes Association and President of the Indian Medical Association, Thiruvananthapuram. Dr. Sreejith took his MBBS from Thiruvananthapuram Medical College and Masters in Medicine from Armed Forces Medical College, Pune. He also has a Diploma in Diabetology from Vuk Vrhovac Institute, Zagreb, World Health Organisation Collaborating center. He is the Editor of the Kerala Medical Journal and the Secretary of the Thiruvananthapuram Diabetes Club.
what is diabetes?
Diabetes simply means an increased amount of glucose in blood. However the condition is not as simple as one might think, in terms of the disease per se and its causes.Most of the food we eat is turned into glucose, a form of sugar. We use glucose as a source of energy to provide power for our muscles and other tissues. Our bodies transport glucose in our blood. In order for our muscles and other tissues to absorb glucose from our blood, we need a hormone called insulin. Without insulin, our bodies cannot obtain the necessary energy from our food.
Insulin is made in a large gland behind the stomach called the pancreas. It is released by cells called beta cells. When a person has diabetes, either their pancreas does not produce the insulin they need, or their body cannot use its own insulin effectively. Many new mechanisms leading to high blood glucose have recently been described. We will see some of the details later.
People with diabetes cannot use enough of the glucose in the food they eat. This leads to the amount of glucose in the blood increasing. This high level of glucose or “high blood sugar” is called hyperglycaemia.All of us have glucose in our blood. Normally, it is <100 mg/dl before food and <140mg/dl after meal. In a diabetic patient this level increases to >126 mg/dl before and >200 mg/dl after food. The values in between Diabetes and normal ranges include impaired fasting glucose (IFG) and impaired glucose tolerance (IGT). These conditions are otherwise called pre-diabetes. Thus we have three sets of values as shown in the table below.
There are many ways to check the blood glucose values. Usually we check the glucose level in the blood, drawn from a vein using a syringe or from the capillaries obtained by a finger prick. A fasting sample has to be taken after eight hours of overnight fasting. After meal blood is drawn two hours after breakfast. Ideally the post meal value should be obtained from a blood sample drawn two hours after consuming 75gm glucose dissolved in a glass of water.
Diabetes is usually associated with some symptoms like Increased thirst, urination and unexplained weight loss. If someone has these symptoms even one value of blood glucose more than 200 mg/dl will define diabetes. However, if someone does not have the classical symptoms of Diabetes, then a repeat check up done on a different day also has to be abnormal before the person can be labeled as Diabetic. Another method to diagnose Diabetes is by doing a test called HbA1C. Hb (Hemoglobin) is the pigment which gives red colour to blood. Some of the Hemoglobin in the blood would combine with glucose. This is known as glycated Hemoglobin (Hb A1C). The glycated hemoglobin level can be estimated by some special techniques. The normal level is <5.4 %. If it’s more than 6.5%, the person is diabetic. Estimation of HbA1C has an advantage over blood glucose. The lifespan of the red blood cells is three months. Hence glycated hemoglobin gives an estimate of the blood glucose over the past three months. Blood glucose estimation can tell us the value only at that particular point of time. However HbA1C estimation has some limitations as well. In our country the standardization is not proper and all the A1C results we get may not be accurate. HbA1C estimation is difficult and also is eight to ten times more costly than blood sugar estimation and is therefore not yet very popular in India for diagnosis of Diabetes.If someone has the symptoms of Diabetes he should check the blood glucose value to find out whether they are high. Even if there are no symptoms it is good to check blood glucose once in a while. We have some specific guidelines in this regard which will be detailed later. It is very important that Diabetes is detected and treated early. We have many new evidences coming up in this regard. So the message is clear – if in doubt check now, the earlier the better.
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