Diabetes Mellitus – Types, Causes, Symptoms and Complications

Diabetes mellitus is a group of metabolic diseases characterized by high blood sugar (glucose) levels, which result from defects in insulin secretion, or action, or both. Diabetes mellitus, commonly referred to as diabetes (as it will be in this article) was first identified as a disease associated with “sweet urine,” and excessive muscle loss in the ancient world.

Diabetes is a serious, lifelong condition that affects an estimated 20.8 million people. About 30 percent (6.2 million) do not know they have it. Each year, about 1.5 million people find out they have diabetes (1) and probably have had the disease for seven years before it was diagnosed.
Diabetes is a metabolic disorder affecting the way the body uses digested food for growth and energy. As a person eats, digestive juices break down the food into a simple sugar called glucose. Glucose is the main source of fuel for the body.

Types of Diabetes Mellitus:

Type 1 diabetes mellitus can occur at any age and is characterized by the marked and progressive inability of the pancreas to secrete insulin because of autoimmune destruction of the beta cells. It commonly occurs in children, with a fairly abrupt onset; however, newer antibody tests have allowed for the identification of more people with the new-onset adult form of type 1 diabetes mellitus called latent autoimmune diabetes of the adult (LADA).

Symptoms of type 1 diabetes:

· Increased thirst
· Increased urination
· Weight loss in spite of increased appetite

Type 2 diabetes mellitus was once called adult-onset diabetes. Now, because of the epidemic of obesity and inactivity in children, type 2 diabetes mellitus is occurring at younger and younger ages. Although type 2 diabetes mellitus typically affects individuals older than 40 years, it has been diagnosed in children as young as 2 years of age who have a family history of diabetes.

Symptoms of type 2 diabetes:

· Blurred vision
· Slow-healing infections
· Impotence in men

Genetic causes — Many people with type 2 diabetes have a family member with type 2 diabetes or conditions commonly associated with diabetes, such as high blood lipid levels, high blood pressure, or obesity. As an example, 39 percent of patients with type 2 diabetes have at least one parent with the disease. The lifetime risk that a first-degree relative (sister, brother, son, daughter) will develop diabetes is five to ten times higher than that of a person of a similar age and weight who has no family history of diabetes.


People with diabetes may experience many serious, long-term complications. Some of these complications begin within months of the onset of diabetes, although most tend to develop after a few years. Most of the complications are progressive. The more tightly a person with diabetes is able to control the levels of sugar in the blood, the less likely it is that these complications will develop or become worse.

The eyes can be affected in several ways by diabetes mellitus. Diabetic retinopathy is one of the leading causes for irreversible blindness in the United States. This retinopathy can occur with either type I or type II diabetes mellitus, usually a decade or so after the onset of diabetes. Most persons with type I diabetes and many of those with type II diabetes develop some background (non-proliferative ) retinopathy. Proliferative retinopathy is more ominous and is more likely to occur when diabetes mellitus is poorly controlled.