Type 2 diabetes mellitus is also known as the non-insulin-dependent diabetes mellitus (NIDDM). It is a chronic disease affecting the metabolism of glucose which is the main fuel of the human body and the principal source of energy for all body cells. Glucose is obtained from the ingested food as well as from the body stores - the liver and muscles. During food digestion, glucose is absorbed from the intestine into the blood circulation from where it enters the cells with the help of insulin. Insulin is a hormone produced by the pancreas. When we eat, insulin is secreted into the blood where it circulates and enables glucose to enter the cells, thereby lowering the blood glucose level. The decrease in blood glucose concentration in turn results in a diminished insulin secretion from the pancreas.
About type 2 diabetes
Diabetes mellitus is one of the most common diseases in the world. It affects 2.8% of the world population. Of all diabetic patients, 80-90% suffer from type 2 diabetes. The disease usually manifests after the age of 40, most commonly around the age of 55. The number of cases is steadily increasing; scientists believe that in 15 years the number of patients will double. Worldwide, there are vast differences in the incidence of this disease-- for instance, certain Native American tribes exhibit a high incidence while in some African territories the incidence is low. These differences can be accounted for by different genetic predispositions as well as different environmental influences.
Disease beginning
Type 2 diabetes mellitus appears due to a decreased action and effect of insulin on the cells. This may be reflected on three levels:
- As a defective secretion of insulin from the pancreas,
- As a cellular resistance to insulin,
- As a defective secretion of glucose from the liver.
It is not entirely clear why a diminished insulin sensitivity develops. Genes apparently play an important role--the incidence of the disease in identical twins is almost 100%. However, besides genetic reasons some other risk factors also contribute to the development of type 2 diabetes mellitus, such as obesity (the more fat tissue in the body, the more resistant the cells become to the effects of insulin), insufficient physical activity, a family history of diabetes, gestational diabetes as well as prediabetes. Prediabetes is a condition in which the blood sugar level is higher than normal, but not high enough to be classified as type 2 diabetes mellitus.
Symptoms
The signs and symptoms of diabetes can be very unspecific at first sight. Many years may pass before a diagnosis is made. The signs of diabetes are the result of hyperglycemia which means an increased blood sugar concentration. The symptoms include increased thirst and frequent urination, insatiable appetite, weight loss, fatigue, visual disturbances and slowly healing wounds. The complications of type 2 diabetes mellitus develop over a lengthy time period. The sooner the disease is discovered, the lower the risk of complications which include cardiovascular diseases (atherosclerotic coronary artery disease, myocardial infarction and hypertension), nerve lesions (neuropathies -- the patients feel paresthesias (prickling), numbness, a burning feeling or pain), kidney disorders (in the late stage, complications may include kidney failure which is treated by a kidney transplant), lesions in the eyes (blindness may result), lesions of the foot soles (an amputation may become necessary), osteoporosis and Alzheimer's disease.
Disease diagnosis
To check for this disease, the standard first thing to do is to take a detailed history of the patient's complaints. Based on the description of the complaints, the physician will soon suspect diabetes mellitus. However, in order to prove it unequivocally, a laboratory blood test must be performed to show an increased blood sugar level. To that effect, an oral glucose tolerance test (OGTT) is most often performed which involves measuring the blood sugar concentration after the patient has ingested a specifically determined amount of glucose.